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User:Marshallsumter/Radiation astronomy1/Opticals

In popular culture optical astronomy encompasses a wide variety of observations via telescopes that are sensitive in the range of visible light. Scientists would call this visible-light astronomy. It includes imaging, where a picture of some sort is made of the object; photometry, where the amount of light coming from an object is measured, spectroscopy, where the distribution of that light with respect to its wavelength is measured, and polarimetry where the polarisation state of that light is measured.

Scientists use the term optical astronomy to mean astronomy at infrared, visible and ultraviolet wavelengths (i.e. observations using either infrared, visible or ultraviolet wavelengths of light). Observations at these wavelengths generally use optical components (mirrors, lenses and solid state digital detectors).

Astronomy
Def. astronomy using observations using telescopes and recording media that capture visible light is called optical astronomy.

Def. astronomy using infrared, visible and/or ultraviolet wavelengths is called optical astronomy.

Radiation
"The radio quasar 3C 454.3 underwent an exceptional optical outburst lasting more than 1 year and culminating in spring 2005. The maximum brightness detected was R = 12.0, which represents the most luminous quasar state thus far observed (MB ~ −31.4). In order to follow the emission behaviour of the source in detail, a large multiwavelength campaign was organized by the Whole Earth Blazar Telescope (WEBT). Continuous optical, near-IR and radio monitoring was performed in several bands. ToO pointings by the Chandra and INTEGRAL satellites provided additional information at high energies in May 2005."

Radiation may affect materials and devices in deleterious ways:
 * 1) By causing the materials to become radioactive (mainly by neutron activation, or in [the] presence of high-energy gamma radiation by photodisintegration).
 * 2) By nuclear transmutation of the elements within the material including, for example, the production of Hydrogen and Helium which can in turn alter the mechanical properties of the materials and cause swelling and embrittlement.
 * 3) By radiolysis (breaking chemical bonds) within the material, which can weaken it, cause it to swell, polymerize, promote corrosion, cause belittlements, promote cracking or otherwise change its desirable mechanical, optical, or electronic properties.
 * 4) By formation of reactive compounds, affecting other materials (e.g. ozone cracking by ozone formed by ionization of air).
 * 5) By ionization, causing electrical breakdown, particularly in semiconductors employed in electronic equipment, with subsequent currents introducing operation errors or even permanently damaging the devices.

Rays
Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light. Geometric optics treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces. Physical optics is a more comprehensive model of light, which includes wave effects such as diffraction and interference that cannot be accounted for in geometric optics.

Although visible light itself extends from approximately 4000 Å to 7000 Å (400 nm to 700 nm), the same equipment used at these wavelengths is also used to observe some near-ultraviolet and near-infrared radiation.

Quartzes
Optical astronomy includes those portions of ultraviolet, visual, and infrared astronomy that benefit from the use of quartz crystal or silica glass telescope components. Fused quartz is manufactured by fusing (melting) naturally occurring quartz crystals of high purity at approximately 2000 °C, using either an electrically heated furnace (electrically fused) or a gas/oxygen-fuelled furnace (flame fused). Fused quartz is normally transparent. The optical and thermal properties of fused quartz are superior to those of other types of glass due to its purity. For these reasons, it finds use in situations such as semiconductor fabrication and laboratory equipment. It has better ultraviolet transmission than most other glasses, and so is used to make lenses and other optics for the ultraviolet spectrum.

Silicas
Fused silica is produced using high-purity silica sand as the feedstock, and is normally melted using an electric furnace, resulting in a material that is translucent or opaque. (This opacity is caused by very small air bubbles trapped within the material.)

Synthetic fused silica is made from a silicon-rich chemical precursor usually using a continuous flame hydrolysis process which involves chemical gasification of silicon, oxidation of this gas to silicon dioxide, and thermal fusion of the resulting dust (although there are alternative processes). This results in a transparent glass with an ultra-high purity and improved optical transmission in the deep ultraviolet.

"UV grade" synthetic fused silica (sold under various tradenames including "HPFS", "Spectrosil" and "Suprasil") has a very low metallic impurity content making it transparent deeper into the ultraviolet. An optic with a thickness of 1 cm will have a transmittance of about 50% at a wavelength of 170 nm, which drops to only a few percent at 160 nm. However, its infrared transmission is limited by strong water absorptions at 2.2 μm and 2.7 μm. "Infrared grade" fused quartz (tradenames "Infrasil", "Vitreosil IR" and others) which is electrically fused, has a greater presence of metallic impurities, limiting its UV transmittance wavelength to around 250 nm, but a much lower water content, leading to excellent infrared transmission up to 3.6 μm wavelength. All grades of transparent fused quartz/fused silica have nearly identical physical properties. The water content (and therefore infrared transmission of fused quartz and fused silica) is determined by the manufacturing process. Flame fused material always has a higher water content due to the combination of the hydrocarbons and oxygen fueling the furnace forming hydroxyl (OH) groups within the material. An IR grade material typically has an [OH] content of <10 parts per million.

The optical dispersion of fused silica can be approximated by the following Sellmeier equation:

 * $$\varepsilon = n^2 = 1 + \frac{0.69616630\lambda^2}{\lambda^2 - 0.0684043^2} + \frac{0.4079426\lambda^2}{\lambda^2 - 0.11624140^2} + \frac{0.8974794\lambda^2}{\lambda^2 - 9.896161^2},$$

where the wavelength $$\lambda$$ is measured in micrometers.

This equation is valid between 0.21 and 3.71 micrometers and at 20 °C. Its validity was confirmed for wavelengths up to 6.7 $$\mu$$m. Experimental data for the real (refractive index) and imaginary (absorption index) parts of the complex refractive index of fused quartz is available over the spectral range from 30 nm to 1000 $$\mu$$m. online.

Lenses
For the case of a [double-convex] lens of thickness d in air, and surfaces with radii of curvature R1 and R2, the effective focal length f is given by:

 * $$\frac{1}{f} = (n-1) \left[ \frac{1}{R_1} - \frac{1}{R_2} + \frac{(n-1)d}{n R_1 R_2} \right],$$

where n is the refractive index of the lens medium. The quantity 1/f is also known as the optical power of the lens.

In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower optical power) leads to higher magnification and a narrower angle of view; conversely, shorter focal length or higher optical power is associated with a wider angle of view.

The 35 mm lens in the image at right has an aperture range of $$f/2.0$$ to $$f/22.$$

The lens at right uses a standard f-stop scale, which is an approximately geometric sequence of numbers that corresponds to the sequence of the powers of the square root of 2:  $$f/1,$$ $$f/1.4$$ $$f/2,$$ $$f/2.8,$$ $$f/4,$$ $$f/5.6,$$ $$f/8,$$ $$f/11,$$ $$f/16,$$ [and] $$f/22.$$

The sequence above is obtained by approximating the following exact geometric sequence:

 * $$f/1 = \frac{f/1}{(\sqrt{2})^0},$$

 * $$f/1.4 = \frac{f/1}{(\sqrt{2})^1},$$

 * $$f/2 = \frac{f/1}{(\sqrt{2})^2},$$

 * $$f/2.8 = \frac{f/1}{(\sqrt{2})^3},$$

Mirrors
Typical requirements for grinding and polishing a curved mirror ... require the surface to be within a fraction of a wavelength of light of a particular conic shape.

Telescopes use front silvered or first surface mirrors, where the reflecting surface is placed on the front (or first) surface of the glass (this eliminates reflection from glass surface ordinary back mirrors have). Some of them use silver, but most are aluminium, which is more reflective at short wavelengths than silver. All of these coatings are easily damaged and require special handling. They reflect 90% to 95% of the incident light when new. The coatings are typically applied by vacuum deposition. A protective overcoat is usually applied before the mirror is removed from the vacuum, because the coating otherwise begins to corrode as soon as it is exposed to oxygen and humidity in the air. Front silvered mirrors have to be resurfaced occasionally to keep their quality.

Cold mirrors are dielectric mirrors that reflect the entire visible light spectrum, while efficiently transmitting infrared wavelengths. These are the converse of hot mirrors.

Hot mirrors reflect infrared light while allowing visible light to pass. These can be used to separate useful light from unneeded infrared to reduce heating of components in an optical device. They can also be used as dichroic beamsplitters. (Hot mirrors are the converse of cold mirrors.)

Actuators
Active optics is a technology used with reflecting telescopes developed in the 1980s, which actively shapes a telescope's mirrors to prevent deformation due to external influences such as wind, temperature, mechanical stress. Without active optics, the construction of 8 metre class telescopes is not possible, nor would telescopes with segmented mirrors be feasible.

Adaptives
Def. an optical system in telescopes that reduces atmospheric distortion by dynamically measuring and correcting wavefront aberrations in real time, often by using a deformable mirror is called adaptive optics.

"Already it has allowed ground-based telescopes to produce images with sharpness rivalling those from the Hubble Space Telescope. The technique is expected to revolutionize the future of ground-based optical astronomy."

The slow-motion simulation at right is typical for adaptive optics operation of a telescope. "The left hand side shows what a point source (e.g. small star) would look like through a ground-based telescope without adaptive optics correction. The right hand side shows what is seen after adaptive optics correction has been applied. Note that the adaptive optics corrected image is normally very compact, but occasionally it "breaks up". If long exposure images are taken, the adaptive optics correction produces a sharp point at the centre of the image, while the uncorrected image is just a large fuzzy blob. Note that the pattern changes much more quickly when adaptive optics correction is applied. This can make it difficult to use adaptive optics corrected telescopes in an astronomical interferometer or for speckle imaging."

Colors
The visible spectrum is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of frequency, this corresponds to a band in the vicinity of 400–790 THz. A light-adapted eye generally has its maximum sensitivity at around 555 nm (540 THz), in the green region of the optical spectrum (see: luminosity function).

There are several cases of astronomers who claimed that following a cataract operation, they could see shorter wavelengths than other people, slightly into the ultraviolet.

Entities
Johannes Kepler's Rudolphine Tables (1627) are regarded as the most accurate and comprehensive star catalogue and planetary tables published up until that time. It contained the positions of over 1000 stars and directions for locating the planets within our solar system. Kepler finished the work in 1623 and dedicated it to his patron, the Emperor Rudolf II, but actually published it in 1627. The table's findings support Kepler's laws and the theory of a heliocentric astronomy.

Objects
The 1910 approach, which came into naked-eye view around 10 April and came to perihelion on 20 April, was notable for several reasons: it was the first approach of which photographs exist, and the first for which spectroscopic data were obtained. Furthermore, the comet made a relatively close approach of 0.15AU, making it a spectacular sight. Indeed, on 19 May, the Earth actually passed through the tail of the comet. One of the substances discovered in the tail by spectroscopic analysis was the toxic gas cyanogen, which led astronomer Camille Flammarion to claim that, when Earth passed through the tail, the gas "would impregnate the atmosphere and possibly snuff out all life on the planet." His pronouncement led to panicked buying of gas masks and quack "anti-comet pills" and "anti-comet umbrellas" by the public. In reality, as other astronomers were quick to point out, the gas is so diffuse that the world suffered no ill effects from the passage through the tail.

"It is quite possible that [faint streamers preceding the main tail and lying nearly in the prolonged radius vector] may have touched the Earth, probably between May 19.0 and May 19.5, [1910,] but the Earth must have passed considerably to the south of the main portion of the tail [of Halley's comet]."

Of the other planets of the solar system, Mercury, Mars, Jupiter, Saturn, Uranus, and Neptune, none has apparently produced as much drama and excitement recently on Earth among some of the intelligent life forms as Halley's comet.

Mars made its closest approach to Earth and maximum apparent brightness in nearly 60,000 years, 55,758,006 km (0.372719 AU), magnitude −2.88, on 27 August 2003 at 9:51:13 UT.

Still much further away from the Earth than the Sun or Neptune are the many stars and nebulae that make up the Milky Way. Beyond the confines of our galaxy is the Andromeda Galaxy imaged on the left.

Of the Local Group, “[i]ts two dominant galaxies, the Milky Way and Andromeda (M31), are separated by a distance of ~700 kpc and are moving toward each other with a radial velocity of about -117 km s-1 (Binney & Tremaine 1987, p. 605).” "making [Andromeda] one of the few blueshifted galaxies. The Andromeda Galaxy and the Milky Way are thus expected to collide in about 4.5 billion years, although the details are uncertain since Andromeda's tangential velocity with respect to the Milky Way is only known to within about a factor of two. A likely outcome of the collision is that the galaxies will merge to form a giant elliptical galaxy. Such events are frequent among the galaxies in galaxy groups. The fate of the Earth and the Solar System in the event of a collision are currently unknown. If the galaxies do not merge, there is a small chance that the Solar System could be ejected from the Milky Way or join Andromeda.

Strong forces
"The molecular cloud Cepheus B is subject to strong forces both trying to compress and to disrupt it simultaneously."

Weak forces
"The observation of a neutrino burst within 3 h of the associated optical burst from supernova 1987A in the Large Magellanic Cloud provides a new test of the weak equivalence principle, by demonstrating that neutrinos and photons follow the same trajectories in the gravitational field of the galaxy."

Continua
An active galactic nuclear optical continuum emission is visible whenever there is a direct view of the accretion disc. Jets can also contribute to this component of the AGN emission. The optical emission has a roughly power-law dependence on wavelength.

Absorptions
"The right figure shows the absorption length as a function of depth. The bulk of the scientifically-useful optical sensors in AMANDA are embedded between 1500 and 1900 m beneath the surface."

"The optical properties of in situ ice beneath the south pole are measured by a combination of in situ N2 lasers, DC lamps, and YAG laser pulses from the surface. The properties vary with depth due to climatological variation such as ice ages. [...] The two properties that most strongly affect the reconstruction capabilities of AMANDA-II are absorption and scattering."

"The absorption strongly depends on wavelength. Notice [in the figure at right] that the absorption also depends on depth at wavelengths where the absorption coefficient is relatively small. For short wavelengths, the absorption coefficient is small and dust contributes significantly, which is responsible for the depth dependence. At 532nm, the absorption coefficient is large, and the value is largely determined by intrinsic properties of ice (i.e, the roll of dust is less obvious)."

"The [second figure at right] shows the average scattering coefficent (1/scattering_length) as a function of depth. Note that the effective scattering length, L_eff, is (approximately) the average length to isotropize the direction of all but 1/e of the photons. This important parameter for diffusion calculations is related to the geometric scattering length by L_eff=L_geo/(1-). The solid curve shows the coefficient of the scattering length for 400 nm light. Other colors behave differently due to the slight dependence of the scattering length on wavelength."

"At depths below 1400m, dust is responsible for light scattering in ice. The rapid rise in scattering at shallow depths (relative to the surface) is due to onset of air bubbles trapped in the ice. The dashed blue line shows the intrinsic scattering from dust in the region dominated by air bubbles."

The "maximum absorption length is slightly more than 100m at AMANDA-II depths, but the scattering length is only 20m for wavelengths that correspond to the longest absorption lengths."

"For quenched galaxies, the Hα absorption trough is deep and can be traced through the nucleus and along the major axis. It extends to a radius at or beyond 2 Rd [where Rd is the galaxy disk scale length] in all but three cases. This makes it possible to determine a velocity width from the optical spectrum as is done for emission line flux, with appropriate corrections between stellar and gas velocities (see discussion in Paper I, also Neistein, Maoz, Rix, & Tonry, 1999). In the few cases where a velocity width can also be measured from the H I data, it is found to be in good agreement with that taken from the Hα absorption line flux."

Bands
Spectral bands are part of optical spectra of polyatomic systems, including condensed materials, large molecules, etc. Each line corresponds to one level in the atom splits in the molecules. When the number of atoms is large, one gets a continuum of energy levels, the so called "spectral bands". They are often labeled in the same way as the monatomic lines.

Meteors
Micrometeoroids are extremely common in space. These tiny particles are a major contributor to space weathering processes. When they hit the surface of the Moon, or any airless body (Mercury, the asteroids, etc.), the resulting melting and vaporization causes darkening and other optical changes in the regolith.

Electrons
"Each [optical module] OM contains a 10 inch [photo-multiplier tube] PMT that detects individual photons of Cerenkov light generated in the optically clear ice by muons and electrons moving with velocities near the speed of light."

Gamma rays
Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the most luminous electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several minutes, although a typical burst lasts 20–40 seconds. The initial burst is usually followed by a longer-lived "afterglow" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).

Indices
The color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. To measure the index, one observes the magnitude of an object successively through two different filters, such as U and B, or B and V, where U is sensitive to ultraviolet rays, B is sensitive to blue light, and V is sensitive to visible (green-yellow) light (see also: UBV system). The set of passbands or filters is called a photometric system. The difference in magnitudes found with these filters is called the U-B or B–V color index, respectively. The smaller the color index, the more blue (or hotter) the object is. Conversely, the larger the color index, the more red (or cooler) the object is. This is a consequence of the logarithmic magnitude scale, in which brighter objects have smaller (more negative) magnitudes than dimmer ones. For comparison, the yellowish Sun has a B–V index of 0.656 ± 0.005, while the bluish Rigel has B–V –0.03 (its B magnitude is 0.09 and its V magnitude is 0.12, B–V = –0.03). The passbands most optical astronomers use are the UBVRI filters, where the U, B, and V filters are as mentioned above, the R filter passes red light, and the I filter passes infrared light. These filters were specified as particular combinations of glass filters and photomultiplier tubes.

Filters
A Photometric system is a set of well-defined passbands (or filters), with a known sensitivity to incident radiation. The sensitivity usually depends on the optical system, detectors and filters used. For each photometric system a set of primary standard stars is provided.

Polars
Light given off by a star is un-polarized, i.e. the direction of oscillation of the light wave is random. However, when the light is reflected off the atmosphere of a planet, the light waves interact with the molecules in the atmosphere and they are polarized.

Ultraviolets
Ultraviolet astronomy is radiation astronomy applied to the ultraviolet phenomena of the sky, especially at night. It is also conducted above the Earth's atmosphere and at locations away from the Earth as a part of explorational (or exploratory) ultraviolet astronomy.

In ultraviolet-optical astronomy, images may yield important information. The image at right "is the most detailed view of the largest stellar nursery in our local galactic neighborhood. The massive, young stellar grouping, called R136, is only a few million years old and resides in the 30 Doradus Nebula, a turbulent star-birth region in the Large Magellanic Cloud (LMC), a satellite galaxy of our Milky Way. There is no known star-forming region in our galaxy as large or as prolific as 30 Doradus. Many of the diamond-like icy blue stars are among the most massive stars known. Several of them are over 100 times more massive than our Sun. These hefty stars are destined to pop off, like a string of firecrackers, as supernovas in a few million years. This image, taken in ultraviolet, visible, and red light by Hubble's Wide Field Camera 3, spans about 100 light-years. The nebula is close enough to Earth that Hubble can resolve individual stars, giving astronomers important information about the birth and evolution of stars in the universe. The Hubble observations were taken Oct. 20-27, 2009. The blue color is light from the hottest, most massive stars; the green from the glow of oxygen; and the red from fluorescing hydrogen."

Visuals
What is “the “old-fashioned” spirit of real-time visual astronomy”? “I think everyone can conjure up a mental image of astronomers at every level and place in history, gazing through the eyepieces of their telescopes at sights far away - true visual astronomy.”

Violets
"In 1997 we observed comet Hale-Bopp with the 2.6 m Nordic Optical Telescope on La Palma, Canary Islands, with a view to estimating the 12C/13C abundance ratio. About twenty high-resolution (λ /Δ λ ~ 70000) spectra of the strong CN Violet (0,0) band were secured with the SOFIN spectrograph from 7 to 13 April. The heliocentric and geocentric distances of the comet were then close to 0.9 AU and 1.4 AU, respectively. While the data do show the expected lines of the 13C14N isotopic molecule, we have been surprised to find in addition a number of very weak features, which are real and turn out to be positioned very near to the theoretical wavelengths of lines pertaining to the R branch of 12C15N."

Infrareds
Infrared astronomy deals with the detection and analysis of infrared radiation (wavelengths longer than red light). Except at wavelengths close to visible light, infrared radiation is heavily absorbed by the atmosphere, and the atmosphere produces significant infrared emission. Consequently, infrared observatories have to be located in high, dry places or in space. The infrared spectrum is useful for studying objects that are too cold to radiate visible light, such as planets and circumstellar disks. Longer infrared wavelengths can also penetrate clouds of dust that block visible light, allowing observation of young stars in molecular clouds and the cores of galaxies. Some molecules radiate strongly in the infrared. This can be used to study chemistry in space; more specifically it can detect water in comets.

"The NASA/ESA Hubble Space Telescope has been at the cutting edge of research into what happens to stars like our Sun at the ends of their lives. One stage that stars pass through as they run out of nuclear fuel is the preplanetary, or protoplanetary nebula. This Hubble image at right of the Egg Nebula shows one of the best views to date of this brief but dramatic phase in a star’s life.

The preplanetary nebula phase is a short period in the cycle of stellar evolution — over a few thousand years, the hot remains of the star in the centre of the nebula heat it up, excite the gas, and make it glow as a planetary nebula. The short lifespan of preplanetary nebulae means there are relatively few of them in existence at any one time. Moreover, they are very dim, requiring powerful telescopes to be seen. This combination of rarity and faintness means they were only discovered comparatively recently. The Egg Nebula, the first to be discovered, was first spotted less than 40 years ago, and many aspects of this class of object remain shrouded in mystery.

At the centre of this image, and hidden in a thick cloud of dust, is the nebula’s central star. While we can’t see the star directly, four searchlight beams of light coming from it shine out through the nebula. It is thought that ring-shaped holes in the thick cocoon of dust, carved by jets coming from the star, let the beams of light emerge through the otherwise opaque cloud. The precise mechanism by which stellar jets produce these holes is not known for certain, but one possible explanation is that a binary star system, rather than a single star, exists at the centre of the nebula.

The onion-like layered structure of the more diffuse cloud surrounding the central cocoon is caused by periodic bursts of material being ejected from the dying star. The bursts typically occur every few hundred years.

The distance to the Egg Nebula is only known very approximately, the best guess placing it at around 3000 light-years from Earth. This in turn means that astronomers do not have any accurate figures for the size of the nebula (it may be larger and further away, or smaller but nearer). This image is produced from exposures in visible and infrared light from Hubble’s Wide Field Camera 3.

Infrared and optical astronomy are often practiced using the same telescopes, as the same mirrors or lenses are usually effective over a wavelength range that includes both visible and infrared light.

Submillimeters
Stars "believed to have circumstellar disks similar to the primitive solar nebula [are] based on the criteria [...]:
 * 1) high far-infrared optical depths around visible stars,
 * 2) shallow spectral energy densities longward of 5 µm, and
 * 3) large millimeter-wave flux densities indicative of ≳ 0.01 M⊙ of H2."

Superluminals
"The arrival times of the Cerenkov photons in 6 optical sensors determine the direction of the muon track."

"The optical requirements on the detector medium are severe. A large absorption length is needed because it determines the required spacing of the optical sensors and, to a significant extent, the cost of the detector. A long scattering length is needed to preserve the geometry of the Cerenkov pattern. Nature has been kind and offered ice and water as natural Cerenkov media. Their optical properties are, in fact, complementary. Water and ice have similar attenuation length, with the roles of scattering and absorption reversed. Optics seems, at present, to drive the evolution of ice and water detectors in predictable directions: towards very large telescope area in ice exploiting the long absorption length, and towards lower threshold and good muon track reconstruction in water exploiting the long scattering length."

"The Baikal experiment represents a proof of concept for future deep ocean projects that have the advantage of larger depth and optically superior water."

"With the attenuation length peaking at 55m near 470 nm, the site is optically similar to that of the best deep water sites investigated for neutrino astronomy."

"Astronomy, whether in the optical or in any other wave-band, thrives on a diversity of complementary instruments, not on “a single best instrument”."

Rocky objects
"The formation of Earth-like planets through collisional accumulation of rocky objects within a disk has mainly been explored in theoretical and computational work in which post-collision ejecta evolution is typically ignored1,2,3, although recent work has considered the fate of such material4. [...] An important ingredient in understanding the vanishing mid-infrared excess emission toward TYC 8241 2652 1 is the initial state of its disk system. Given an age of ~10 Myr, the star could have been host to either an accreting protoplanetary disk rich in gas and dust or a second-generation debris disk formed from the collisions of rocky objects orbiting the star13. [...] the dusty material orbiting TYC 8241 2652 1 is the result of the collisions of rocky objects."

"To determine the age of TYC 8241 2652 1 we obtained high-resolution optical spectra over four epochs from February 2008 to January 2009 with an echelle spectrograph mounted on the Siding Spring Observatory 2.3-m telescope. [...] The spectral type and effective temperature is determined from line ratios28 in the Siding Spring Observatory echelle spectra."

Shelters
"The Canada-France-Hawaii Telescope (CFHT) is a 3.6 m optical-infrared telescope located on the summit of Mauna Kea on the island of Hawaii." The CFHT is at an altitude of 4,204 meters. Mauna Kea last erupted 4,000 to 6,000 years ago [~7,000 b2k]. The Mauna Kea Observatories are used for scientific research across the electromagnetic spectrum from visible light to radio, and comprise the largest such facility in the world.

Spectroscopy
Astronomical spectroscopy is the technique of spectroscopy used in astronomy. The object of study is the spectrum of electromagnetic radiation, including visible light, which radiates from stars and other celestial objects. Spectroscopy can be used to derive many properties of distant stars and galaxies, such as their chemical composition, but also their motion by Doppler shift measurements.

Mercury
"Optical reflectance studies of Mercury provide evidence for Mg silicates."

Earth
"For outside wave fields of the Moon and the Earth accept seismic and acoustic waves which characteristic frequencies first of all coincide with frequencies of orbital and own rotation of cosmogony objects (planets and their satellites, multiple star systems, pulsars)."

"Besides wave (acoustic) processes in the top Earth atmosphere and also those from that its are accompanied also by optical effects (polar lights) and strongly connected with gas dust streams acting [4]."

Asteroids
When narrowband spectrophotometric observations are made of outer-belt asteroids separated by "their average distance from the Sun (3.21, 3.64, 3.78 and 4.29 au respectively) ... the slope in their 0.5-1 μm spectra (scaled to 1 at 0.7 μm) increases with solar distance. ... this compositional gradation [may extend] through the orbits of Saturn, Uranus and Neptune. ... Because the ion solar flux varies as the inverse square of the distance from the Sun, one expects, as in fact observed, the surfaces of D and P type asteroids become blacker as the distance from the Sun decreases."

Iapetus
The optical reflectance spectra from "the leading hemisphere of Iapetus" over a range of ~0.35 to ~0.82 μm is rather closely matched by optical reflectance spectra "from frozen CH4 (T ~ 10 K) bombarded by ~ 1016 protons (1.5 MeV)cm-2 [organic 1]".

"The spectrum of the Iapetus (dark) leading hemisphere is redder and resembles that of D-type asteroids (Cruikshank et al., 1983). The spectrum of organic 1 fits that at the lower λ but is more reflecting at λ > 0.7 μm. As a matter of fact the spectrum of the Iapetus leading hemisphere is the sum of two contributions: that from the dark units and from the ice-rich bright polar caps."

Phoebe
The optical reflectance spectra from Phoebe over a range of ~0.35 to ~0.82 μm is very closely matched by optical reflectance spectra "from frozen CH4 (T ~ 10 K) bombarded by ... ~ 1017 protons [1.5 MeV] cm-2 [organic 2]".

"Phoebe's spectrum ... is very similar to that of C-type asteroids ... and is well fitted by the laboratory carbonized material (organic 2)."

Neptune
At right is a set of images from different years for Neptune. These images "show that Neptune's brightness has increased significantly since 1996. The rise is due to an increase in the amount of clouds observed in the planet's southern hemisphere. These increases may be due to seasonal changes caused by a variation in solar heating. Because Neptune's rotation axis is inclined 29 degrees to its orbital plane, it is subject to seasonal solar heating during its 164.8-year orbit of the Sun. This seasonal variation is 900 times smaller than experienced by Earth because Neptune is much farther from the Sun. The rate of seasonal change also is much slower because Neptune takes 165 years to orbit the Sun. So, springtime in the southern hemisphere will last for several decades! Remarkably, this is evidence that Neptune is responding to the weak radiation from the Sun. These images were taken in visible and near-infrared light by Hubble's Wide Field and Planetary Camera 2."

Mira B

Some data suggest that Mira B is a normal main sequence star of spectral type K and roughly 0.7 solar masses, rather than a white dwarf as first envisioned.

Analysis in 2010 of rapid optical brightness variations has indicated that Mira B is in fact a white dwarf.

Camelopardalis
The official IAU sky chart for the constellation Camelopardalis is at right with notable sources marked and located.

"A bright star [in the image at left] is surrounded by a tenuous shell of gas in this unusual image from the NASA/ESA Hubble Space Telescope. U Camelopardalis, or U Cam for short, is a star nearing the end of its life. As it begins to run low on fuel, it is becoming unstable. Every few thousand years, it coughs out a nearly spherical shell of gas as a layer of helium around its core begins to fuse. The gas ejected in the star’s latest eruption is clearly visible in this picture as a faint bubble of gas surrounding the star."

"U Cam is an example of a carbon star. This is a rare type of star whose atmosphere contains more carbon than oxygen. Due to its low surface gravity, typically as much as half of the total mass of a carbon star may be lost by way of powerful stellar winds."

"Located in the constellation of Camelopardalis (The Giraffe), near the North Celestial Pole, U Cam itself is actually much smaller than it appears in Hubble’s picture. In fact, the star would easily fit within a single pixel at the centre of the image. Its brightness, however, is enough to overwhelm the capability of Hubble’s Advanced Camera for Surveys making the star look much bigger than it really is. The shell of gas, which is both much larger and much fainter than its parent star, is visible in intricate detail in Hubble’s portrait. While phenomena that occur at the ends of stars’ lives are often quite irregular and unstable (see for example Hubble’s images of Eta Carinae, potw1208a), the shell of gas expelled from U Cam is almost perfectly spherical."

"The image was produced with the High Resolution Channel of the Advanced Camera for Surveys [using the 606 nm and 814 nm filters]."

Carina
At left is the IAU sky chart for the constellation Carina with notable sources located.

"NGC 3199, in the constellation Carina, [...] is the wind-blown partial "ring" around the Wolf-Rayet (W-R) star WR 18 (aka HD 89358), the easternmost (leftmost) of the three bright blue stars near the center of the 2MASS image. NGC 3199 and WR 18 are at a distance of about 3.6 kpc (11,736 light years) from us. W-R stars represent the final evolutionary stages of very massive stars (with ~30 solar masses or greater). The nebula shows an asymmetric appearance, i.e., only one side (the western one) of the shell is bright, both in the optical and the near-infrared. The fainter, eastern side is there, but is much fainter. Some W-R ring nebulae can be seen in 2MASS images, such as the more complete ring around M1-67. But, NGC 3199 is particularly bright in the 2MASS data. Dyson & Ghanbari (1989, A&A, 226, 270) provided an explanation for the ring's appearance through a model where a moving WR 18 is blowing a strong stellar wind into a surrounding uniform interstellar medium. Vigorous mass loss of 10-5 to 10-4 solar masses per year is characteristic of W-R stars, as the star approaches the end of its short life, although not all are surrounded by ring nebulae."

Centaurus
"This image [at left] of the planetary nebula SuWt 2 reveals a bright ring-like structure encircling a bright central star. The central star is actually a close binary system where two stars completely circle each other every five days. The interaction of these stars and the more massive star that sheds material to create the nebula formed the ring structure. The burned out core of the massive companion has yet to be found inside the nebula. The nebula is located 6,500 light-years from Earth in the direction of the constellation Centaurus. This color image was taken on Jan. 31, 1995 with the National Optical Astronomy Observatory's 1.5-meter telescope at the Cerro Tololo Inter-American Observatory in Chile."

Gemini
At left is a multiwavelength composite that shows the supernova remnant IC 443, also known as the Jellyfish Nebula. Fermi GeV gamma-ray emission is shown in magenta, optical wavelengths as yellow, and infrared data from NASA's Wide-field Infrared Survey Explorer (WISE) mission is shown as blue (3.4 microns), cyan (4.6 microns), green (12 microns) and red (22 microns). Cyan loops indicate where the remnant is interacting with a dense cloud of interstellar gas.

Standard candles
Def. an astronomical object that has a known luminosity is called a standard candle.

Def. any astronomical object of known absolute magnitude is called a standard candle.

Standard candles are objects that belong to some class that [has] a known brightness. By comparing the known luminosity of the latter to its observed brightness, the distance to the object can be computed using the inverse square law. These objects of known brightness are termed standard candles. ... The apparent magnitude, or the magnitude as seen by the observer, can be used to determine the distance D to the object in kiloparsecs (where 1 kpc equals 1000 parsecs) as follows:

 * $$\begin{smallmatrix}5 \cdot \log_{10} \frac{D}{\mathrm{kpc}}\ =\ m\ -\ M\ -\ 10,\end{smallmatrix}$$

where m the apparent magnitude and M the absolute magnitude. ... [B]oth magnitudes must be in the same frequency band and there can be no relative motion in the radial direction. The difference between absolute and apparent magnitudes is called the distance modulus, and astronomical distances, especially intergalactic ones, are sometimes tabulated in this way.

Standard stars
"An internally consistent and homogeneous list of standard stars on the Johnson-Kron-Cousins broadband UBVRI photometric system" are published in a set of articles:
 * 1) 223 stars in the magnitude range from 7 to 17,
 * 2) 526 stars in the magnitude range 11.5 < V < 16.0, and
 * 3) 202 stars completing the magnitude range 8.90 < V < 16.30.

Cosmic distance ladders
The cosmic distance ladder (also known as the Extragalactic Distance Scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are "close enough" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances with methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.
 * Light green boxes: Technique applicable to star-forming galaxies.
 * Light blue boxes: Technique applicable to Population II galaxies.
 * Light Purple boxes: Geometric distance technique.
 * Light Red box: The planetary nebula luminosity function technique is applicable to all populations of the Virgo Supercluster.
 * Solid black lines: Well calibrated ladder step.
 * Dashed black lines: Uncertain calibration ladder step.

Astrography
Light pollution obscures the stars in the night sky for city dwellers [and] interferes with astronomical observatories. Light is particularly problematic for amateur astronomers, whose ability to observe the night sky from their property is likely to be inhibited by any stray light from nearby. Most major optical astronomical observatories are surrounded by zones of strictly enforced restrictions on light emissions.

In addition to skyglow, light trespass can impact observations when artificial light directly enters the tube of the telescope and is reflected from non-optical surfaces until it eventually reaches the eyepiece. This direct form of light pollution causes a glow across the field of view which reduces contrast. Light trespass also makes it hard for a visual observer to become sufficiently dark adapted. The usual measures to reduce this glare, if reducing the light directly is not an option, include flocking the telescope tube and accessories to reduce reflection, and putting a light shield (also usable as a dew shield) on the telescope to reduce light entering from angles other than those near the target. Under these conditions, some astronomers prefer to observe under a black cloth to ensure maximum dark adaptation.

H.E.S.S. is located on the Cranz family farm, Göllschau, in Namibia, near the Gamsberg, an area well known for its excellent optical quality. The first of the four telescopes of Phase I of the H.E.S.S. project went into operation in Summer 2002; all four were operational in December 2003.

Astrohistory
Historical astronomy is the science of analysing historic astronomical data. The American Astronomical Society (AAS), established in 1899, states that its Historical Astronomy Division "...shall exist for the purpose of advancing interest in topics relating to the historical nature of astronomy. By historical astronomy we include the history of astronomy; what has come to be known as archaeoastronomy; and the application of historical records to modern astrophysical problems." Historical and ancient observations are used to track theoretically long term trends, such as eclipse patterns and the velocity of nebular clouds. Conversely, utilizing known and well documented phenomenological activity, historical astronomers apply computer models to verify the validity of ancient observations, as well as dating such observations and documents which would otherwise be unknown.

Astromathematics
"Kepler's laws:
 * 1) The orbit of every planet is an ellipse with the Sun at one of the two foci.
 * 2) A line joining a planet and the Sun sweeps out equal areas during equal intervals of time.
 * 3) The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.

The diagram at the right illustrates Kepler's three laws of planetary orbits: (1) The orbits are ellipses, with focal points ƒ1 and ƒ2 for the first planet and ƒ1 and ƒ3 for the second planet. The Sun is placed in focal point ƒ1. (2) The two shaded sectors A1 and A2 have the same surface area and the time for planet 1 to cover segment A1 is equal to the time to cover segment A2. (3) The total orbit times for planet 1 and planet 2 have a ratio a13/2 : a23/2.

Astrophysics
Def. a straight line along which an observer has a clear view is called line of sight.

In the section on 'senses' above is a demonstration of the principle of 'line of sight'; i.e., "a line from an observer's eye to a distant point toward which [the observer] is looking". In the image on the left of rain beneath a dark cloud, there is a highway with a vehicle on it. The vehicle is further away from the observer than the right turn onto a side road. Is the blue sky behind the dark cloud? Is the line of trees in the background further away than the dark cloud? Many objects in this image and the others can be layered relative to the observer (some are closer by inspection than others). These layers or strata are strata along the line of sight. The principle of line of sight can be used to make deductions about the relative locations (or positions) of objects from the observer's perspective.

By observing many of the wandering lights in the night sky, an occasional occultation of the light of one astronomical object may occur by the intervention of another along a closer astronomical stratum. On April 25, 1838, an occultation of Mercury by the Moon occurred when Mercury was visible to the unaided eye after sunset. An occultation of Venus by the Moon occurred "on the afternoon of October 14", 1874. An earlier such occultation "occurred on May 23, 1587, and is thus recorded by [Tycho Brahe] in his Historia Celestis". "Thomas Street, in his Astronomia Carolina (A.D. 1661), mentions three occultations by Venus, being two occasions when the planet covered Regulus, and once when there was an occultation of Mars by Venus." "[Thomas Street] describes [the occultation of Mars by Venus] as follows: "1590,. Oct. 2nd, 16h. 24s. Michael Mœstlin observed ♂ eclipsed by ♀.""

Def. the turning or bending of any wave, such as a light or sound wave, when it passes from one medium into another of different optical density is called refraction.

Sciences
At right is a copy of the title page of Johannes Kepler's Rudolphine Tables (1627). It is regarded as the most accurate and comprehensive star catalogue and planetary tables published up until that time. It contained the positions of over 1000 stars and directions for locating the planets within our solar system.

Technology
Technology is the making, usage, and knowledge of tools, machines, techniques, crafts, systems or methods of organization in order to solve a problem or perform a specific function. It can also refer to the collection of such tools, machinery, and procedures.

Telescopes
Def. a monocular optical instrument possessing magnification for observing distant objects is called a telescope.

An optical telescope gathers and focuses light mainly from the visible part of the electromagnetic spectrum (although some work in the infrared and ultraviolet).

Most radiation telescopes, especially optical telescopes, combine a variety of lenses, mirrors, active and adaptive optics, filters, detectors, mounts, image processing, and observatories, in many locations.

A telescope's imaging system's resolution can be limited either by aberration or by diffraction causing blurring of the image. These two phenomena have different origins and are unrelated. Aberrations can be explained by geometrical optics and can in principle be solved by increasing the optical quality — and cost — of the system. On the other hand, diffraction comes from the wave nature of light and is determined by the finite aperture of the optical elements. The lens' circular aperture is analogous to a two-dimensional version of the single-slit experiment. Light passing through the lens interferes with itself creating a ring-shape diffraction pattern, known as the Airy pattern, if the wavefront of the transmitted light is taken to be spherical or plane over the exit aperture.

The interplay between diffraction and aberration can be characterised by the point spread function (PSF). The narrower the aperture of a lens the more likely the PSF is dominated by diffraction.

Two point sources are regarded as just resolved when the principal diffraction maximum of one image coincides with the first minimum of the other.

Angular resolution
Def. a quantitative measure of the ability of an optical instrument to produce separable images" is called resolving power.

The angular resolution of an optical telescope is determined by the diameter of the primary mirror or lens gathering the light (also termed its "aperture").

The Rayleigh criterion for the resolution limit $$\alpha_R$$ (in radians) is given by
 * $$\sin(\alpha_R) = 1.22 \frac{\lambda}{D}$$

where $$\lambda$$ is the wavelength and $$D$$ is the aperture. For visible light ($$\lambda$$ = 550 nm) in the small-angle approximation, this equation can be rewritten:
 * $$\alpha_R = \frac{138}{D}$$

Here, $$\alpha_R$$ denotes the resolution limit in arcseconds and $$D$$ is in millimeters. In the ideal case, the two components of a double star system can be discerned even if separated by slightly less than $$\alpha_R$$. This is taken into account by the Dawes limit
 * $$\alpha_D = \frac{116}{D}$$

The equation shows that, all else being equal, the larger the aperture, the better the angular resolution. The resolution is not given by the maximum magnification (or "power") of a telescope. Telescopes marketed by giving high values of the maximum power often deliver poor images.

The log-log plot at right is of aperture diameter vs angular resolution at the diffraction limit for various light wavelengths compared with various astronomical instruments. For example, the blue star shows that the Hubble Space Telescope is almost diffraction-limited in the visible spectrum at 0.1 arcsecs, whereas the red circle shows that the human eye should have a resolving power of 20 arcsecs in theory, though normally only 60 arcsecs.

Clocks
An atomic clock is a clock device that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element. Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS.

The FOCS 1 continuous cold cesium fountain atomic clock started operating in 2004 at an uncertainty of one second in 30 million years. The clock is in Switzerland.

Motion calibrators
POA CALFOS is the improved Post Operational Archive version of the Faint Object Spectrograph (FOS) calibration pipeline ... The current version corrects for image motion problems that have led to significant wavelength scale uncertainties in the FOS data archive. The improvements in the calibration enhance the scientific value of the data in the FOS archive, making it a more homogeneous and reliable resource.

Observatories
Historically, observatories [are] as simple as [using or placing stably] an astronomical sextant (for measuring the distance between stars) or Stonehenge (which has some alignments on astronomical phenomena). ... Most optical telescopes are housed within a dome or similar structure, to protect the delicate instruments from the elements. Telescope domes have a slit or other opening in the roof that can be opened during observing, and closed when the telescope is not in use. In most cases, the entire upper portion of the telescope dome can be rotated to allow the instrument to observe different sections of the night sky. Radio telescopes usually do not have domes.

The "Great Observatories Origins Deep Survey (GOODS) [...] are primarily, but not exclusively, based on multi–band imaging data obtained with the Hubble Space Telescope (HST) and the Advanced Camera for Surveys (ACS). [...] Existing deep observations from the Chandra X-ray Observatory (CXO) and groundbased facilities are supplemented with new, deep imaging in the optical and near-infrared from the European Southern Observatory (ESO) and from the Kitt Peak National Observatory (KPNO) [includes deep] observations with the Space Infrared Telescope Facility (SIRTF) [and] at the Kitt Peak National Observatory, National Optical Astronomical Observatories".

"Observations [of 64 neglected double stars] were made with the GRAS002 robotic [optical] telescope located at the Remote Astronomical Society Observatory [at] Mayhill, [New Mexico] NM, USA (http://www.remote-astronomical-society.org/)."

The double stars [were] imaged using a Takahashi Mewlon 300 Dall-Kirkham cassegrainian reflector located at the Remote Astronomical Society Obseervatory in Mayhill, New Mexico."

The GTC began its preliminary observations on 13 July 2007, using 12 segments of its primary mirror, made of Zerodur glass-ceramic by the German company Schott AG. Later the number of segments was increased to a total of 36 hexagonal segments fully controlled by an active optics control system, working together as a reflective unit. Its Day One instrumentation [is the Optical System for Imaging and low Resolution Integrated Spectroscopy] OSIRIS. Scientific observations began properly in May 2009.

Deep space surveillance
At left is an image of the US counterpart, the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) base at Diego Garcia, British Indian Ocean Territory latitude 7.41173°S and longitude 72.45222°E.

Printing
The invention of the printing press (an early example is shown at right) made it possible for scientists and politicians to communicate their ideas with ease, leading to the Age of Enlightenment; an example of technology as a cultural force.

Adaptive optics
"Adaptive optics (AO) systems have been in operation for roughly 30 years. As the field matures increased numbers of possible applications are being discovered however their practical implementation has been greatly limited by the high cost, high power consumption, and size of traditional adaptive optics systems."

In "the development of micro-machined electro-mechanical systems (MEMS) based adaptive optics elements [... in] particular electrostatic membrane mirrors [1], and nematic liquid crystal based devices [2] [...] a proof-of-concept demonstration of these two devices [is] for imaging bright low earth orbit (LEO) solar illuminated satellites through atmospheric turbulence, performed on the Air Force Research Laboratory, Directed Energy Directorate’s 3.67 meter AEOS telescope on Haleakala Maui. The aperture was stopped done to 1.12 meters in order to match the number of actuators and dynamic range of the devices."

Hypotheses

 * 1) Most of the early research was centered on improving optical astronomy.


text:
Reverse genetics

Reverse genetics is an approach to discovering the function of a gene by analyzing the phenotypic effects of specific gene sequences obtained by DNA sequencing. This investigative process proceeds in the opposite direction of so-called forward genetic screens of classical genetics. Simply put, while forward genetics seeks to find the genetic basis of a phenotype or trait, reverse genetics seeks to find what phenotypes arise as a result of particular genes.

Automated DNA sequencing generates large volumes of genomic sequence data relatively rapidly. Many genetic sequences are discovered in advance of other, less easily obtained, biological information. Reverse genetics attempts to connect a given genetic sequence with specific effects on the organism.

Techniques used in reverse genetics
To learn the influence a sequence has on phenotype, or to discover its biological function, researchers can engineer a change or disruption in the DNA. After this change has been made a researcher can look for the effect of such alterations in the whole organism. There are several different methods of reverse genetics that have proved useful:

Directed deletions and point mutations
Site-directed mutagenesis is a sophisticated technique that can either change regulatory regions in the promoter of a gene or make subtle codon changes in the open reading frame to identify important amino residues for protein function.

Alternatively, the technique can be used to create null alleles so that the gene is not functional. For example, deletion of a gene by gene targeting (gene knockout) can be done in some organisms, such as yeast, mice and moss. Unique among plants, in Physcomitrella patens, gene knockout via homologous recombination to create knockout moss is nearly as efficient as in yeast. In the case of the yeast model system directed deletions have been created in every non-essential gene in the yeast genome. In the case of the plant model system huge mutant libraries have been created based on gene disruption constructs. In gene knock-in, the endogenous exon is replaced by an altered sequence of interest.

In some cases conditional alleles can be used so that the gene has normal function until the conditional allele is activated. This might entail ‘knocking in’ recombinase sites (such as lox or frt sites) that will cause a deletion at the gene of interest when a specific recombinase (such as CRE, FLP) is induced. Cre or Flp recombinases can be induced with chemical treatments, heat shock treatments or be restricted to a specific subset of tissues.

Another technique that can be used is TILLING (see TILLING (molecular biology)). This is a method that combines a standard and efficient technique of mutagenesis with a chemical mutagen such as Ethyl methanesulfonate (EMS) with a sensitive DNA screening-technique that identifies single base mutations (also called point mutations) in a target gene.

Gene silencing
The discovery of gene silencing using double stranded RNA, also known as RNA interference (RNAi), and the development of gene knockdown using Morpholino oligos, have made disrupting gene expression an accessible technique for many more investigators. This method is often referred to as a gene knockdown since the effects of these reagents are generally temporary, in contrast to gene knockouts which are permanent.

RNAi creates a specific knockout effect without actually mutating the DNA of interest. In C. elegans, RNAi has been used to systematically interfere with the expression of most genes in the genome. RNAi acts by directing cellular systems to degrade target messenger RNA (mRNA).

While RNA interference relies on cellular components for efficacy (e.g. the Dicer proteins, the RISC complex) a simple alternative for gene knockdown is Morpholino antisense oligos. Morpholinos bind and block access to the target mRNA without requiring the activity of cellular proteins and without necessarily accelerating mRNA degradation. Morpholinos are effective in systems ranging in complexity from cell-free translation in a test tube to in vivo studies in large animal models.

Interference using transgenes
A molecular genetic approach is the creation of transgenic organisms that overexpress a normal gene of interest. The resulting phenotype may reflect the normal function of the gene.

Alternatively it is possible to overexpress mutant forms of a gene that interfere with the normal (wildtype) genes function. For example, over expression of a mutant gene may result in high levels of a non-functional protein resulting in a dominant negative interaction with the wildtype protein. In this case the mutant version will out compete for the wildtype proteins partners resulting in a mutant phenotype.

Other mutant forms can result in a protein that is abnormally regulated and constitutively active (‘on’ all the time). This might be due to removing a regulatory domain or mutating a specific amino residue that is reversibly modified (by phosphorylation methylation or ubiquitination). Either change is critical for modulating protein function and often result in informative phenotypes.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Reverse genetics


text:
User:Cpt.Daniel

/Syndication Bot

/TAO-Draft

/TAO-Handbook-Draft /TAO-CoP-Draft General Drafts

title: User:Cpt.Daniel


text:
User:TAOBot/Syndication

Status: In Progress

Purpose
Crawling the project-related pages and provide a newsfeed.

Performed Actions: The output format has to be php, so it can be used by a php script. Link to all given namespaces: https://www.mediawiki.org/wiki/Manual:Namespace
 * api.php?action=query&list=categorymembers&cmtitle=Category:TAO&cmlimit=100 (get all category pages related to TAO, default 10)
 * api.php?action=query&list=categorymembers&cmtitle=Category:TAO&cmnamespace=3&cmlimit=100 (get all category talk pages related to TAO, default 10)
 * api.php?action=query&list=categorymembers&cmtitle=Category:TAO&cmnamespace=6&cmlimit=100(get all category file pages related to TAO, default 10)
 * api.php?action=query&list=watchlistraw&wrlimit=500 (get the raw watchlist of the bot)
 * api.php?action=query&list=alllinks&alunique=&alprefix=TAO&allimit=200
 * api.php?action=query&list=alllinks&alunique=&alprefix=TAO&alnamespace=3&allimit=200 (get all pages with TAO prefix from the talk pages)
 * api.php?action=query&list=alllinks&alunique=&alprefix=TAO&alnamespace=6&allimit=200

title: User:TAOBot/Syndication


text:
User talk:Lorraine25

Things You Should Really Know When Purchasing Your Ideal Home

There are several mistakes that many of us have made over the years when purchasing real estate. If you are on the market to buy a chunk of property, go through this article for some great advice to help avoid making the same mistakes that others have made.

If you are in the marketplace for a top notch home, make certain you learn to decode the language that real estate advertisers use. As a general rough guide, if an advert sounds too fantastic to be true, it probably is too fantastic to be accurate. Make sure you don't fall for advert language as it can cause disappointment.

When purchasing real estate you need to do a little research about the districts you like before looking at any houses. Talk with your real estate agent about what houses have just recently sold for and use that to set some limits that you will not go over. Then when you find a place that grabs you emotionally you will not get carried away into coughing up more than you need to.

In the event you wish to do research on own, 1 technique of finding concealed investment properties is to disburse flyers around a neighborhood in which you'd like to buy. Consider having somebody drop them door to door. One thousand flyers will not cost much and you never can say who might give you a call to discuss or point you in the direction of a property. However use your real estate agent for preparing deals.

If you are thinking of purchasing a home, saving cash now is the key. Most individuals begin to speak about purchasing a home well before they really make the purchase. This is the opportune time to put away cash to reach your deposit goal which is sometimes going to be about 20 percent of the home cost.

Do careful research when you are thinking of purchasing a new piece of real estate. There are many things to consider like location, college rating, and walk-ability score. It is a shame when anyone spends all of their hard earned cash on a property in a bad neighborhood, or one that's some distance from conveniences.

Now that you have read through the info in this article, you are one step nearer to making the purchase that won't haunt you. Learn from the experiences of others so you do not have to learn through a negative experience of your own. Use this info to be successful.

title: User talk:Lorraine25


text: File:TAO-layout startpage-beat.jpg

title: File:TAO-layout startpage-beat.jpg


text:
User:TAOBot

Hello there, we are just starting to experiment with a little bot for the TAO project. Documentation and info will be collected here. Currently we're just prototyping and going down the "quick-and-dirty" road. You'll find more Details here: /Description

We, that is User:Cpt.Daniel, User:semaphor. You can communicate with us by communicating with the Bot, we'll get his mail and watch his talk page: User_talk:TAOBot.

= Work in Progress =
 * /Description: What it is supposed to do (one day).
 * /Syndication: 1st purpose, provide an easy way to keep track of all changes within the project pages.

= ToDo =
 * UserAgent policy: https://meta.wikimedia.org/wiki/User-Agent_policy
 * "Please use GZip compression when making API calls (Accept-Encoding: gzip). Bots eat up a lot of bandwidth, which is not free."

= Help and Info =

Bot

 * https://en.wikipedia.org/wiki/Wikipedia:Creating_a_bot
 * API access libs: https://www.mediawiki.org/wiki/API:Client_code

api.php

 * https://www.mediawiki.org/wiki/API or better https://www.mediawiki.org/w/api.php
 * Possible frameworks (check for state of the project via table in w:en:Wikipedia:Creating_a_bot):
 * https://github.com/kalebheitzman/mediawikibot most tempting option: simply one class
 * http://www.softx.tk/wiki/SoftX:PHPwikiBot a bit more complex than mediawikibot
 * https://github.com/hamstar/Wikimate doesn't seem to provide wanted functionality.

Wordpress

 * Posting via API: https://codex.wordpress.org/XML-RPC_Support
 * e.g. Blogger API: http://code.google.com/apis/blogger/
 * Posting via Email: https://codex.wordpress.org/Post_to_your_blog_using_email

= Service =

First User:TAOBot shall provide an automatically updated feed for the TAO project:
 * Not done yet, shall be automagically filled with all Pages related to TAO project.

 * RSS: https://en.wikiversity.org/w/api.php?action=feedwatchlist&wlowner=TAOBot&wltoken=TAOBotToken&allrev&hours=72&linktodiffs&feedformat=rss
 * Atom: https://en.wikiversity.org/w/api.php?action=feedwatchlist&wlowner=TAOBot&wltoken=TAOBotToken&allrev&hours=72&linktodiffs&feedformat=atom

title: User:TAOBot


text:
Talk:TAO/Concept

Comments on procedure

 * So far less colors, it is just a first sketch. After some feedback, we can take care of that.
 * Wording:
 * Plural form used mostly, singular shall apply as well.

Module VS Learning and research activities
The currently suggested term Module is the equivalent to Wikiversity's Learning and research activities.
 * Should we use the already established but quite oblong term Learning and research activities?!!
 * Another idea: discriminate between Activities and Action? Activities: representations in Wikiversity / Action: all that happens in CoP / i.e. outside Wikiversity, maybe just
 * I'm not so happy with the distinction between "learning" and "research" in the context of the TAO CoP. According to my understanding, in the context of the TAO CoP "research" will primarily take the following forms:
 * (1) Action Research/Action Learning, taking place in close co-operation between researchers and practitioners;
 * (2) Transfer of academic knowledge to practical situations.
 * In (1), doing research and learning from practical challenges kind of go together. In (2) it is mainly the dissemination part of the research process we are focusing on, which, from a practitioner's perspective is "learning".
 * --Beat Estermann 09:53, 21 February 2012 (UTC)
 * As I'm not familiar with most actions going on within and around TAO (besides the Wikiversity part) the "Personas" part was the most difficult for me to put down while creating the graphic. I think we can go with your understanding and just cancel/ignore the distiniction between "learning" and "research", thus resulting in:
 * (1) Using the term "Module" instead of "Learning and research activity", while pointing out (at an adequate prominent place) that we use "Module" synonymical. Effect: adjusted wording wihtin Wikiversity aiming to lessen confusion.
 * (2) Not distinguishing between "learning" and "research" in a distinct and formal way while developing the personas, at least not aming for or focusing on it.
 * Regarding the graphic I think the "Personas" part will remain "under construction" and description and definitions will be found during: TAO/Creating_Personas_and_Working_with_Them. Maybe I'll find some time to remove the formal distinction between "learning" and "research" which the table currently found there suggests.
 * --Simon Lüke 00:09, 23 February 2012 (UTC)

General Comments

 * A Glossary can easily derived from the graphic (Community of Practice; Module: previously going under the term "handbook", "Chapters" of a handbook could be seen as modules; Ressource: somehow smallest entity, normally a page in Wikiverisity, which used this term in the first place.; ...)
 * While creating the graphic Simon experieced the connection between learnig and research activity. While trying to document things became much more clear.

title: Talk:TAO/Concept


title: File:Math.2.B.Hilbert.20120216.pdf


text:
User:Deakin2074

/enes100/

title: User:Deakin2074


text:
User:TAOBot/Description

 * User:TAOBot's development is (in the first place and at current time) driven by a "getting-things-done" principle and shall bring immediate support the people working on project TAO.
 * User:TAOBot shall be used by one or mutliple scripts run on one of our hosts (cronjob) and mainly use api.php.
 * Documetation for the project done on the userpages. Source code will be free and open.
 * Purposes:
 * 1) Keeping track of all pages related to the project:
 * 2) Crawling Wikiversity for pages prefixed by TAO or tagged by categories of the project (TAO, TAO Module, ...); namespaces: main, talk, files, maybe more.
 * 3) Fill its own watchlist with the results of the crawl. This watchlist can be used by erveryone via Syndication; Token: TAOBotToken
 * 4) Maintain a list of all crawled pages on a site of the project. For easy reference by users.
 * 5) Alert or get into action if prefixed and categorized pages desync.
 * 6) Provide an interface or view on all changes of pages belonging to the project. Ideas so far:
 * 7) Fill a simple Wordpress blog with changes containing diffs, so users can watch changes in their browser not having to maintain their personal watchlist, can individually subscribe by email.
 * 8) Testing will take place at http://tao.zawiw-ulm.de/

title: User:TAOBot/Description


title: File:Pea2.s12.sec45.c.djvu


text:
User talk:Saibo

 Hello Saibo, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

To get started, you may

 * Take a guided tour and learn to edit.
 * Visit a (kind of) random project.
 * Browse Wikiversity, or visit a portal corresponding to your educational level: pre-school, primary, secondary, tertiary, non-formal education.
 * Find out about research activities on Wikiversity.
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You don't need to be an educator to edit. You only need to be bold to contribute and to experiment with the sandbox or your userpage. See you around Wikiversity! --Katarighe (Talk · Contributions · E-mail) 17:28, 16 February 2012 (UTC) --Katarighe (Talk · Contributions · E-mail) 17:28, 16 February 2012 (UTC)

title: User talk:Saibo


text:
User talk:Petrb

 Hello Petrb, and welcome to Wikiversity! If you need help, feel free to visit my talk page, or contact us and ask questions. After you leave a comment on a talk page, remember to sign and date; it helps everyone follow the threads of the discussion. The signature icon in the edit window makes it simple. All users are expected to abide by our Privacy policy, Civility policy, and the Terms of Use while at Wikiversity.

To get started, you may

 * Take a guided tour and learn to edit.
 * Visit a (kind of) random project.
 * Browse Wikiversity, or visit a portal corresponding to your educational level: pre-school, primary, secondary, tertiary, non-formal education.
 * Find out about research activities on Wikiversity.
 * Explore Wikiversity with the links to your left.

 * Read an introduction for teachers and find out how to write an educational resource for Wikiversity.
 * Give feedback about your initial observations
 * Discuss Wikiversity issues or ask questions at the colloquium.
 * Chat with other Wikiversitans on #wikiversity-en.
 * Follow Wikiversity on twitter (http://twitter.com/Wikiversity) and identi.ca (http://identi.ca/group/wikiversity).

You don't need to be an educator to edit. You only need to be bold to contribute and to experiment with the sandbox or your userpage. See you around Wikiversity! --Katarighe (Talk ) 17:31, 16 February 2012 (UTC) --Katarighe (Talk ) 17:31, 16 February 2012 (UTC)

title: User talk:Petrb


text:
User:Bsimon21

Engineering student focusing on the biomedical and material science aspects of engineering.

 * /enes100/

title: User:Bsimon21


title: File:Pea2.s12.sec45.d.djvu


text:
User talk:EGM4313.spr12.team5.wallace

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 * File:IEAplot1.jpg
 * File:IEAplot2.jpg
 * File:Partthree.jpg
 * File:Parttwo.jpg
 * File:Ptthree.jpg

MaintenanceBot (discuss • contribs) 03:44, 11 November 2013 (UTC)

title: User talk:EGM4313.spr12.team5.wallace


text:
User talk:Egm.4313.s12.team2.bblackwell

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title: User talk:Egm.4313.s12.team2.bblackwell


text:
Engineering Projects/Power projects/Howard Community College

 * /Fall2012/
 * /Spring2012/


text:
Engineering Projects/Robot end effector/Howard Community College

 * /Spring2012/


text:
3D Scan/Kinect Makerbot/Howard Community College/Spring2012

 * /P1550jme/
 * /P1501msn/
 * /p21550Kinect_Robotic_Car/
 * /p31550Kinect_Robotic_Car/


text:
Category:Howard Community College spring2012

Here are the personal and team web pages that were worked on during the spring of 2012 at Howard Community College, Columbia Maryland USA.


text:
Engineering Projects/Power projects/Howard Community College/Spring2012

 * /p1550KMN/

 * /p2550TK/

 * /p3550K/


text:
Engineering Projects/Rubberband gun/Howard Community College/spring2012

 * /p1550jbf/
 * /p1501jds/
 * /p1501kmd 3/


text:
Engineering Projects/HoverCraft/Howard Community College/Spring2012

 * /p1550JJIW/

 * /p2550JW/

 * /p3550W/


text:
Engineering Projects/StrandBeest/Howard Community College/spring2012

 * /p1550MWSY/

 * /p2550YFC/

 * /p3550cf/


text:
Helicopter/Howard Community College/Spring2012

 * /p502JASS/
 * /p2502JASS/
 * /p3502JASS/


text:
Engineering Projects/Model boat/Howard Community College/Spring2012

/p1501-ZlM/


text:
Engineering Projects/Car Hack/Howard Community College/Spring2012

/p1501kmd/

/p1501kmd 2/


text:
Engineering Projects/Robot end effector/Howard Community College/Spring2012

 * /p1501mjj/
 * /p1501mjj2/
 * /p1501mjj3/


text:
Engineering Projects/Coanda/Howard Community College/Spring2012

/p501acm/

/p501acm2.0/

/p501cm3.0/


text:
User:2jjones

Justin Jones Engineering undergaduate student at Howard Community College, Columbia, Maryland, USA

These are the class projects I am involved in.

 * /enes100/

title: User:2jjones


text:
Engineering Projects/Rubberband gun/Howard Community College/spring2012/p1550jbf

Problem Statement
Design and make a rubber band Gatling gun that can reload itself.

Team Members

 * Brittany Simon
 * mfashola
 * gjaksec

Summary
The main problem past teams have had is that the rubber bands were getting stuck on each other and not firing off. We made a design that would simplify the firing process, but toward the end of the allotted time, it became evident that we would not be able to use our plan. The gun was built very closely to the design displayed below, which is very similar to the Disintegrator. design. The gun ultimately failed to work properly, however. The only reason for this is that we decided to make the Gatling gun out of cardboard, due to recourse and time constraints. The problem is that, when the trigger rotates around to the wedge, the frame is not strong enough to hold the wedge in place. This results in the trigger simply pushing the wedge out of the way and therefor not firing.

Story
The first step we took was to choose a design. as previously stated, we chose the Disintegrator design. After deciding on the design, we drew the rubber band gun, firing mechanism, and gear piece, in the 3D drafting software known as "123D". This process took an unexpected to two weeks to complete, mostly because nobody in the team had ever used 3D drafting software and had to learn it. When the drawings were complete, we bought everything on the materials list and began constructing the gun. The guns construction was completed during the fourth week of the project in time to present on that week's Thursday.

Decision List
[Design Decision]

This is the main decision we had to make. Every other move we made just followed the design we chose, except one. The only other decision was to use 6 total barrels as apposed to 12

Material List

 * - Two 45" x .25" x 40" sheets of shipping cardboard
 * - Box cutter
 * - Scissors
 * - Ruler
 * - Pencil
 * - Hot glue gun
 * - A large supply of hot glue sticks
 * - Rubber Bands (3.5 in/po. x .25 in/po.)
 * - Two Electric Screw Drivers
 * - "Magnum 12" 12 shot firing mechanism pieces
 * - 6ft of quarter inch wooden dowel
 * - 6ft of half inch wooden dowel
 * - 3' x 3' x .25" sheet of balsa wood
 * - Electric Drill
 * - Saw

Software List
Software that the team used during this project was "123D," which is a tree dimensional drafting program, and the Maker-Bot software. The 123D software war used to draw the Gatling Gun itself, along with the gear and firing mechanism box, and the Maker-Bot software was used to create the gears for the firing mechanism.

3D drawing of Gear in 123D

3D drawing of Firing Mechanism Box in 123D

Time

 * 38hrs 45min

Tutorials

 * - Cut six 30cm x 10cm rectangles out of the cardboard (these will be the sides of the barrels)
 * - Cut one 30cm x 30cm square for the base
 * - Cut four 30cm x 6cm pieces for the vertical post
 * - Cut out 24 firing mechanism pieces, whose dimension can be fount in the software section link
 * - Hot glue the vertical post pieces into a rectangular prism, then to the base
 * - Cut four 10cm equal lateral triangles to be fitted to the ends of the barrels
 * - Glue barrels together like in the Gatling gun picture(triangular prism)
 * - Glue a 6cm by 6cm cardboard piece to the top of the vertical post
 * - Glue a 6cm section of the quarter inch dowel to the top of the post
 * - Glue the frame pieces together as depicted in the pictures
 * - Drill .25" hole into center of the frame and insert onto the post
 * - Cut two 40cm sections of quarter inch dowel rod
 * - Drill .25inch holes into the centers of both ends of both barrels and insert each dowel rod
 * - Drill the same holes into the ends of the frame and fit barrels like picture
 * - Cut six 14cm sections of half inch dowel rod, cut notches into one end of each section
 * - Glue one of these sections to each vertex of the barrels such as in the pictures
 * - Cut out 18, 4cm sections of .25" dowel rod
 * - Construct Firing Mechanism boxes by inserting one of the recently cut out dowel pieces into each of the three holes.
 * - Then put the gear on the isolated peg, and the trigger facing away from the gear on the middle peg. Then glue the other side on.
 * - Glue each firing box behind each .5" dowel on each barrel vertex
 * - Screw, and glue a screw into the end of each dowel from the barrels
 * - Attach created wedge pieces behind triggers
 * - Now you are done, all you have to do is screw the screw with the screwdriver after loading the rubber bands

Next Steps
The next steps in this project would be to finish the second barrels, and then to begin designing an automatic reloading system.


text:
3D Scan/Kinect Makerbot/Howard Community College/Spring2012/P1550jme

Problem Statement
Use the Kinect to capture a 3D image and print it using the Maker Bot

Team Members

 * Javiereduturcios
 * Mir07
 * Eshipley
 * Engsihn

Summary
Three-dimensional (3D) scanning has been increasing in popularity as a worthwhile project for engineers because it is a valuable tool to use in a multitude of applications. Using the Kinect, the team is going to capture a real-time model of a 3D object. This type of 3D model capturing is new to the world of 3D scanning and modeling. Once we have a model stored we will have many ways to push the project forward including printing the model with the MakerBot or changing the file format for purposes of reverse engineering. Originally, 3D models were created from polygons made up of vertices and compiled in Standard Tesselation Language (STL) format. In the 80s and 90s an algorithmic mathematical model commonly used in computer graphics for generating and representing curves and surfaces called non-uniform rational basis spline (NURBS) became popular and is commonly used today in programs such as Computer Aided Design (AutoCAD). 3D scanning works like radar. Sets of vertices in three-dimensional coordinate system, known as point clouds, are created using a camera, computer software, and electromagnetic radiation (namely visible light, lasers, laser lines, or infared projection dots in the case of the kinect). With geometric analysis the computer software finds the distance from the camera to the object that is reflecting the radiation. RapidForm XOR is an engineering tool of the future that will allow engineers to quickly and easily convert point clouds into solid surfaces usable with CAD capabilities. "For years, if you needed to really reverse engineer something, you would scan the part, you’d go through all the work of making the clean mesh and/or NURBS model, and then you’d open it in CAD and manually rebuild a new part model over top of the scanned geometry." Applications of 3D scanning range from testing aerospace structures through test flights, wind tunnels, and Computational Fluid Dynamics (CFD) to creating compression masks for burn victims. "The old method involved taking an impression of the patient’s face using the same material a dentist uses on teeth. This required anesthetizing the patient, and it took approximately 10 hours of OR staff and technician time." Starting this semester at Howard Community College, we want to expand our horizons by creating a fun way to learn through reverse engineering.

Story
''Tell a detailed story of the project. Describe how split up, what the obstacles were, what testing was done, what informal decisions were made, what assumptions were made, what the results were.''

 * With the team decided upon 3D scanning as a project, we presented possible solutions to our professor and peers on how to make 3D scanning applicable at HCC. We needed to convince them

that we could design a system that would be beneficial to others interested in reverse engineering through 3D scanning. Requirements were made regarding which subsytems we were going to use.

Our goal was to use the Microsoft Xbox 360 Kinect and the MakerBot to successfully scan an object and print it.
 * Researching these subsytems led us to create additional requirements for the software programs that we would use for the project. For example, we discovered that the technology is not readily

available to go from 3D scanning directly to 3D printing with the click of a button. Therefore, we searched for a solution that would make the process as straightforward as possible. First, we found a

software to scan objects with the Kinect. Processing is an open source software that we were able to use with the Kinect for scanning. However, it was not coded to create a point cloud of an object

in its 360 degree entirety. One software called ReconstructMe had several successful videos on YouTube, but we were not able to replicate that success. After installing all the drivers, the execution

files still brought up errors stating that a binary file is missing. RGB-Demo was the most successful and intuitive open source software for full 360 degree view 3D scanning that we used. We were

able to run two different execution files for capturing point clouds that are saved as .ply meshes with a single click. However, both these files only captured single perspective views of the object.

RGB-Demo had execution files for programs that we needed to use to capture an object in 360 degrees. One program was to calibrate the Kinect. The execution file ran the prompt in the DOS

window briefly, but it never opened the program window. Whereas, the other was for capturing the point cloud and it would not display the image in the focus of the Kinect in the program window as

seen in YouTube videos. Scanning an object in 360 degrees can be done in multiple ways using the Kinect: either by calibrating and using multiple Kinects (2-3) which RGB-Demo is programmed to

do, by rotating an object in front of the Kinect which can also be done using RGB-Demo, or by moving a Kinect around the object which RGB-Demo was not programmed to do. We only worked with

one Kinect, so we chose to rotate an object in front of the Kinect. This gave us the inspiration we needed to build a turntable to rotate the object. Our first Lazy Susan was made out of a a box

taped to a piece of wood that was attached to a metal ball bearing rotatable bracket that we had to turn by hand. One person took the time to configure a DC motor with an Arduino that turned a

piece of cardboard. Although, scanning an object in its entirety demonstrated a major obstacle that would effect the integrity of our project, we maintained a steady pace and pushed the

project towards its next stages.

 * 3D modelling was the intermediate step of our project, so we evaluated the following 3D modelling software programs: 123D, Maya, Blender, and Meshlab. For the 3D modeling part of our project,

we created tutorials on MeshLab and Blender. Our tutorials explain how to the softwares tools to perform the complex algorithmic approximations that 3D modelling software programs use such as

Normal or Gaussian Distribution. Our tutorials show and teach the steps that are needed to take a point cloud mesh and render it into a manageable and printable object file.

 * In the course of time, we got the hang of using the MakerBot and the Replicator-G software that it uses. We accomplished the arduous task of changing the filament of the MakerBot by heating

it to its target temperature and loosening the thumbscrew that presses the filament wire against the CNC motor. This gave us the option to print 3D objects in either black or white. We obtained

printable models from the internet which we printed for fun and as practice for when we finally created our own .stl file. As we suspected, a rendered .stl made from single perspective point cloud

was not printable. We were able to create our own .stl models using Blender, but have not yet discovered how to attach a base to an object file or mesh that we scanned using the Kinect, so that it

can be printed.

 * 3D scanning turned out to be a constructive project that can be continually worked upon. This project peaked an interest in each of its team members that fueled us to branch out into individual

tasks, be creative, and push the project forward. Finally, we found a sense of achievement by documenting all of our work whether it was testing possible solutions to problems with tools such as

the MakerBot that we did not know existed before this project or creating detailed and concise tutorials that others can follow or use as a blueprint for their own tutorials.

Decision List

 * I. 3D Scanning

1)How does it work?        A)Hardware -kinect -Camera and Laser Line B)Software- To Scan 360 degree              -RGB-Demo v0.7.0               -ReconstrucMe    2)What else might be needed? A)Turntable      B)Open Source Software
 * II. 3D Modeling

1)Sofware      A)Meets Requirements -Easy to use -Accessible B)Fills Multiple Roles         -Sampling and Editing               a)Meshlab b)Autodesk Maya         -Preset Shapes and file types
 * III. 2D Printing

-Minimize required Materials -Keep the scope narrow -Lower -Create Tutorials

Material List
Nothing needs to be purchased for this project, all the software and drivers can be download free of cost.
 * 1. For printing in 3D we needed the MakerBot Cupcake CNC
 * 2. A Computer to open the software to print
 * 3. Microsoft Kinect
 * 4. RgbDemo software
 * 5. Kinect drivers
 * 6. Meshlab

Software List
You installed different software packages or used already installed software. Describ the programs here.
 * 1. AutoCAD, Blender, Google SketchUp to be able to create STL files
 * 2. ReplicatorG, to convert an STL file into GCode and be able to print them

Time

 * 74 hours

Tutorials
Created (Tutorials For Repeating The Project):
 * Scanning An Object Using The Kinect: Full 360 Degree View
 * Scanning With The Kinect (Single Perspective Alternative Using Processing)
 * Cleaning Up Point Cloud Meshes in MeshLab For 3D Printing
 * Tutorial on Blender

Updated:
 * Set Up & Run The MakerBot

Created (Tutorials For Troubleshooting The MakerBot):
 * How to Download 3D programs to build STL files
 * How To: Find Or Create A Printable STL File
 * How to Change the Wire of the Makerbot
 * How to print STL files with letters or Numbers in it

Next Steps
List specific details, advice, describe the current problems that the next team faces associated with the project here.

We successfully scanned objects using the Kinect and converted them to file types that are used by the MakerBot 3D printer. We were unable to scan a full 360 degree view of an object, but we were able to print an object we created in Blender. We had a lot of fun using the MakerBot and finding interesting objects to print with it. We encourage people to choose 3D scanning because it is fun and its applications for reverse engineering in the future are enormous. All of the software and drivers can be found in the tutorials along with the process of installing and running the demo software to get data from Kinect. This project can always be improved upon, but we do feel that we have made significant progress for future students to work through the scanning, modelling, and printing process quickly, so that all the major troubleshooting that was unsolved can be worked on in the first weeks of the project. We accredit that a scanned object will get printed before the next teams final presentation for their project.


text:
Engineering Projects/StrandBeest/Howard Community College/spring2012/p1550MWSY

Problem Statement
Design and Create StrandBeest.

Team Members

 * Mwnuk
 * 9484syoon
 * Brianwcallaghan
 * m'kay m'kay

Summary
We set out to create a strandbeest. The team started with research of potential designs, and there was a general consensus that the original design by Theo Jansen be maintained. A general scale was agreed upon based on Jansen's golden numbers. The next major decision the group had to agree upon was what materials to use. We decided that because we had access to light wood and a CNC router that would be a good place to start.

Story
The group assembled and decided that the best route to tackling the new project was to research the mechanical workings of the leg assemblies. We made several working models and felt it was time to move on to design. We had access to both wood and a large CNC router so we decided that wood might be the best material for our design. We created a CAD drawing with each of the pieces of the assemblies we needed. Once everything was set and the toolpaths were added, we made a test cut with the router. This showed that we needed to add small bridges to hold everything together on the table. With bridges added, we began the cutting of the parts. The bridges were cut by the machine on the second pass, so they would be thin and easy to remove. We also began modeling and testing materials for the crankshaft. This is the area we found the most difficulty. The flat design of the leg assemblies limited the material we could use to prevent a gap between pieces of the leg. The material and that which was holding it together had to be strong enough to hold the weight of the assembly and sturdy enough to do it while moving. Ultimately the crankshaft did not get finished within the time frame of this project.

Decision List
Week 0
 * Researched the design of the leg assembly of the strandbeest.

Week 1
 * Dimensions of the strandbeest were hammered out within the group.
 * Materials and tasking within the group to acomplish several tasks
 * Gathered supplies that are going to be used for this project
 * Made cardboard mock-up of linkage.

Week 2

 * Made designes for pieces to be cut in 123D and AutoCad
 * Imported designs into EnRoute and made adjustments to arrangement.
 * Encountered some trouble importing the files into EnRoute from AutoCAD. Parts of the drawing were not present in the imported file.  Some experimentation showed that the files needed to be both downgraded to an earlier file format and all arrayed elements had to be exploded and reduced to one of each part in AutoCAD before importing.  Each part can then be arrayed or nested in EnRoute.
 * Set toolpaths for cutting in the imported .ROU files and exported them to .CNC files for the router to retrieve.

Week 3

 * Made a test cut with the CNC router. Determined that bridges were necessary to keep the parts still on the machine.
 * Added bridges to both files. These are .5 inch wide connections between the pieces and the board that are left by the cutting table to hold things together.  This is useful with intricate cuts of small parts that could get sucked into the dust collector.
 * Made actual cuts of parts.
 * Assembled a pair of legs to test the movement. The legs touched at the toe and bumped into themselves at the farthest reaches of the rotation.  Adjustments were needed.

Week 4
 * Made a reduction of about 1 inch to the crank radius which caused the leg to move much more smoothly.
 * Drew up 3D model of crankshaft for continued design work.

Material List
1. 2 sheets of 5mm Luann wood, 4 foot by 8 foot.

2. 1/2 " wooden dowel 3 foot

Software List
AutoCAD 2012 was used to do the design of the wooden parts of our StrandBeest. AutoCAD is computer assisted drawing software. Its purpose is precise design.

EnRoute 4 was then used to import the AutoCAD files (saved as .DXF) and prepare for output to the MultiCAM 3000. EnRoute is CAM software. The function of CAM is computer assisted manufacturing. It communicates your drawings and the details of how your parts are to be cut/drilled to the machine which does the cutting. In EnRoute, you can import CAD files, edit them, draw from scratch, set toolpaths, and select cutting tools and order. EnRoute can communicate with and export executable information to most CNC routers, laser cutters, water cutting machines, 3D printers and such equipment.

123D was used to create a 3D model of the crankshaft

Time
41 hours and 13 minutes

Tutorials

 * /Model Leg Assembly/
 * CNC Tutorial

Next Steps
The crank shaft remains the main hurdle at the moment. Possibly consider using circles instead of the arms that I have already cut. This will make them more sturdy and provide counter balance. Once that is ironed out the next clear step is assembly of the Beest. The working Beest will need to be powered. Wind is the obvious choice, but other avenues could be interesting as well.