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User talk:Mj ivan~enwikibooks

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Tesis de Grado EAN Introduccion Objetivos Justificacion Marco Teorico Capitulos

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title: User talk:Mj ivan~enwikibooks


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General Astronomy/The Celestial Sphere

If you look out from an empty field into a dark sky, you will get the impression that you are standing on a flat plate, enclosed by a giant dome. Depth perception fails us for the distant objects we see in the sky. This creates the appearance that all of the stars have the same distance.

The stars appear to move together across the sky during the night, rising in the east and setting in the west, as if they are affixed to the inside of a dome. Because of this, many ancient civilizations believed that a dome really did enclose the Earth. Only a few centuries ago astronomers came to realize that the stars are actually very far away, scattered throughout the Milky Way Galaxy, rather than attached to the inside of a vast sphere.

The old idea remains useful, however. The concept of the celestial sphere provides a simple way of thinking about the appearance of the stars from Earth without the complication of a more realistic model of the universe. Working with the celestial sphere offers a convenient way of describing what we see from Earth. When we refer to the celestial sphere, we are imagining that everything we see on the sky is set on the inside of a huge spherical shell that surrounds the Earth. We will use the reference points of the celestial sphere as the basis for several coordinate systems used to place celestial locations with respect to one another and to us.

The celestial sphere is an imaginary hollow globe that encloses the Earth. The sphere has no defined size. It can be taken to be infinite (or at least really big), with an infinitesimal Earth at the center. The observer is always taken to be at the center of the celestial sphere, even though the observer isn't at the center of the Earth. Our particular position among the stars gives us a particular view. Brighter stars appear closer; stars in nearly the same direction appear nearby each other, even if they are separated by great distances. Our first and most basic look out into the universe is completely stripped of any depth perception.

The celestial sphere can be seen from either of two perspectives. In one perspective, the celestial sphere itself remains still while the Earth turns inside it. In the other perspective, the Earth stands still and the celestial sphere rotates once per day. To an observer on Earth, these two perspectives appear the same. As we think about how we would expect to perceive the rotation of the Earth, we can use this second perspective to guide us.

Everything we see in the sky, we see as though projected onto the celestial sphere. The stars in the constellation Orion, for example, are at a variety of distances, but the differences are imperceptible to us on Earth. Orion's pattern would disappear if we could view it from any other angle or if we could perceive the depth, because the stars would project differently.

Because depth perception is lost, measurements of size are much more difficult. The Sun and the Moon look about the same size in the sky, even though the Sun is really much larger. The Sun appears to be the same size as the moon because the Sun is much farther away simply because the Sun is both 400 times larger in diameter and 400 times farther away than the Moon.

Although we can't easily measure the physical sizes of celestial objects, we can measure their apparent sizes. We do this by measuring the angle an object subtends in the sky. The Sun and the Moon, for example, subtend an angular diameter of half a degree. Most objects in the sky are smaller than this, so it is often convenient to use a smaller measure of angle. For this purpose, astronomers use arc minutes and arc seconds. There are sixty arc minutes in a degree, and sixty arc seconds in an arc minute. Angles this small are near or beyond the limits of ordinary human vision, but they become useful when using a telescope to make observations.

For casual stargazing, observers think about much larger angles. You can easily measure these angles when stargazing by using your hand as your ruler. From arm's length, your index finger has a width of about one degree, your palm measures about ten degrees across, and your full finger-span, including your thumb, is about 25°. This can be useful for estimating the position of a star in the sky, or for gauging the angular separation of two stars.

While the apparent movement of a star across the sky each night, with the celestial sphere, is great, the measurement of an object's movement across the Celestial Sphere as the object drifts through space, is called proper motion, and is measured in arc seconds per year.

To begin thinking about the view of the sky from Earth, we will identify a few points of reference that are fixed to the ground and of importance to astronomers. Some of these are widely known from common experience.

 * A great circle is a circle drawn on the celestial sphere (or any sphere) which has the center of the Earth as its center. On the Earth, the equator is an example of a great circle. Other lines of latitude are not great circles because their center is not at the center of Earth. Lines of longitude are all great circles because they are always centered on Earth's center. A great circle is the largest possible circle that can be drawn on a sphere.
 * The horizon is where earth and sky meet. It is the boundary between the portion of the sky that is blocked by the Earth and the portion that is visible. There is a distinction between the local horizon, which is defined by real objects specific to the observer's location such as trees or buildings, and the idealized horizon, which is what the local horizon would be if the ground were completely flat and there were no obstructions. For hypothetical or idealized cases, astronomers use the idealized horizon.
 * A star's altitude is the angle between it and the horizon.
 * The cardinal points are points on the celestial sphere that are on the horizon and due north, south, east and west. The North point, for example, is the point due north on the horizon.
 * The zenith is the point in the sky directly overhead. It is necessarily true that any point on the horizon is 90° from the zenith.
 * The meridian is the great circle that passes through the North point, the South point, and the zenith and lies on the celestial sphere.

To any observer, regardless of location, these markers stay in the same positions relative to the observer. The zenith is always directly overhead, the horizon is always level, and so on. Observers standing at different places on Earth will have a different view of the sky. An observer in Singapore might see the Sun at the zenith while another observer in New York would not see the Sun at all. These reference points change with the location of the observer.

There are also reference points that are fixed in the sky. These fixed reference points don't move with respect to the stars, but different observers see them in different positions. They are the basis for the fixed coordinate systems that we discuss later. For now, we will identify only the two most useful of these — the celestial poles and the celestial equator.

The celestial equator is an extension of the Earth's equator onto the celestial sphere. If you stand on Earth's equator, the celestial equator will always be directly overhead and pass through the zenith. It will run from the East point up to the zenith and down again to the West point. Anywhere you stand on Earth, the celestial equator will intersect the East and West points on the horizon. The nearer you are to the equator, the nearer the celestial equator come to the zenith. At the North Pole or the South Pole, the celestial equator lines up with the horizon.

Like the celestial equator, the celestial poles are an extension of the Earth's pole onto the celestial sphere. The North Pole extends out into space to create the North Celestial Pole. Likewise the South Pole creates the South Celestial Pole. In the Northern Hemisphere, only the North Celestial Pole is visible because the South Celestial Pole is below the horizon. In the Southern Hemisphere, only the South Celestial Pole is visible. At the equator, the North Celestial and South Celestial Poles would lie on the horizon where the meridian intersects the horizon.

Polaris is called the "North Star." It can be found at the last star on the "handle" of the Small Dipper. The last two stars of the "cup" of the Big Dipper are called the Guardians (or "Pointers"), and point to Polaris in the sky. Polaris is special because the Earth's North Pole points almost exactly towards it. This means that Polaris will always appear to be due north to any observer, and it will always stay in the same position on the sky.

Often, beginning stargazers assume that Polaris must be a very bright or prominent star. This is not really the case. Polaris is only remarkable because it is almost exactly in line with Earth's axis of rotation. Because of this, Polaris always remains at nearly the same place in the sky. For example, Shakespeare made reference to Polaris in the play Julius Caesar:

 * I am constant as the northern star,
 * Of whose true fixed and resting quality
 * There is no fellow in the firmament.
 * Julius Caesar, William Shakespeare's Julius Caesar, III.1.65-68

Though it must be pointed out that Shakespeare actually got it wrong. At the time Shakespeare wrote Julius Caesar Polaris was indeed the pole star but in Julius Ceasar's time Polaris was not the pole star.

The fact that Polaris always stays in the same position due north has given it much fame. It also makes Polaris a useful reference point for navigation — Using geometry, it is easy to show that the angle Polaris or the celestial pole makes with the horizon is equal to the observer's latitude. In the diagram, the angle $$\angle d$$ is the observer's latitude. The pole and the equator are at right angles, so
 * $$\angle d + \angle a = 90^\circ.$$

or $$\angle a = 90^\circ - \angle d.$$ Since the angles in a triangle add to 180°, we know that
 * $$\angle a + \angle b + 90^\circ = 180^\circ.$$

When we combine these two equations, we have $$\angle b = \angle d$$. The angles $$\angle b$$ and $$\angle c$$ are alternate interior angles, so
 * $$\angle b = \angle c$$

and
 * $$\angle d = \angle c,$$

which means that the angle between the pole and the horizon is the same as the observer's latitude. This fact was once used by navigators at sea, who could easily find their latitude by measuring the position of Polaris.

Like many things in astronomy, the celestial sphere can be very difficult to visualize because of its three dimensional geometry. A visit to a planetarium or a session under the night sky can be very helpful to you in developing a conceptual understanding of the celestial sphere. In the absence of the opportunity for these, it can be helpful to try to draw diagrams such as the one at the beginning of this section for yourself.

To begin drawing a celestial sphere such as the one above, you only need to know the latitude of the observer. Then imagine that the spot where the observer is standing is the "top of the world"; draw circle for the earth, and draw an observer standing at the top. Now draw a much larger circle around that; this represents the celestial sphere.

Since our observer is always on top of the Earth, the features on the celestial sphere that are defined relative to the ground will always be in the same position on the sphere. The zenith is the point directly above the observer's head, at the top of the celestial sphere.

The next important reference is the horizon. The horizon will be horizontal on the diagram. Remember that the celestial sphere has no specific size relative to the Earth, regardless of how you've drawn it. Draw the horizon across the middle of the celestial sphere, so that it's center is the same as the center of Earth. Markers such as the horizon are always idealized, so it doesn't matter whether your observer's view of the sky is actually cut off at the position marked by the horizon.

The next reference points we'd like to place are the North Celestial Pole and the South Celestial Pole. Think about what the orientation of the pole should be given the observer's latitude. If the observer is at the equator, the pole should go horizontally through the Earth. If the observer is at one of the poles, the pole should go through the Earth vertically. Extend the Earth's poles out to the celestial sphere and mark the intersections as the North Celestial Pole and the South Celestial Pole.

If we're in the northern hemisphere, the North Celestial Pole will be above the northernmost point on the horizon, and the South Celestial Pole will be on the opposite side of the celestial sphere, below the horizon. If we're in the southern hemisphere, the situation is reversed. Remember to check that the angle the horizon makes with the pole is about the same as the observer's latitude.

For any given latitude, one can build an appropriate celestial sphere. First, consider the sky in relation to the earth. Take the north and south poles and extend them into the sky; these become the north and south celestial poles. The Earth's equator can be projected outward to form the celestial equator. We'll get something that looks like the picture above.

When you're done, you should have a celestial sphere very like the one at the top of this section.

A celestial sphere forms the basis for the application of many coordinate systems. For example, the horizon and the celestial meridian together form the reference circles for giving the position of stars in terms of altitude and azimuth, making it easier for one to find them on the night sky. The celestial sphere is also a natural system for describing the motion of the sun. In order to explore these concepts, however, it is necessary to understand just how the celestial sphere changes for an observer at a given latitude. As we consider the daily rotation of the Earth, we'll see that your perception of the daily motion depends very much on your latitude.

As you look at the sky, your mind will naturally identify obvious patterns. The Big Dipper and Orion are two very prominent groupings of stars, and others stand out all over the celestial sphere. These asterisms are guideposts to the night sky. You can use them to keep your bearings when you look at the sky. The appearance of the night sky has remained much the same for millennia. Many of the ancient civilizations across the globe invented stories about the sky.

Often, the groups of stars are called constellations. Constellations have a very long history in astronomy, dating back thousands of years. Early in the twentieth century, a list of constellations was formally established by the International Astronomical Union, a widely recognized body of astronomers. The IAU identified constellations that would be used in astronomy and defined specific boundaries to unambiguously establish which constellations each star belonged to. It's easy to learn a few of the most prominent constellations so that you can find your way around the night sky. Beginning with a few easy-to-find landmarks you can find the rest by using familiar stars as guideposts.

Another useful guide in the sky is the ecliptic. The ecliptic is an imaginary line in the sky that the sun draws. The ecliptic is even with the plane of the Earth's orbit around the sun; thus, all of the main planets and the moon should be found relatively close or on the ecliptic, because the solar system is mostly flat. Also, along the ecliptic are the 12 constellations of the zodiac. Thus, by finding some of the main zodiac constellations in the night sky, one can determine if certain objects they see may or may not be planets by whether or not they lie on the ecliptic.

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

title: General Astronomy/The Celestial Sphere


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General Astronomy/Coordinate Systems

Suppose you are an astronomer in America. You observe an exciting event (say, a supernova) in the sky and would like to tell your colleagues in Europe about it. Suppose the supernova appeared at your zenith. You can't tell astronomers in Europe to look at their zenith because their zenith points in a different direction. You might tell them which constellation to look in. This might not work, though, because it might be too hard to find the supernova by searching an entire constellation. The best solution would be to give them an exact position by using a coordinate system.

On Earth, you can specify a location using latitude and longitude. This system works by measuring the angles separating the location from two great circles on Earth (namely, the equator and the prime meridian). Coordinate systems in the sky work in the same way.

The equatorial coordinate system is the most commonly used. The equatorial system defines two coordinates: right ascension and declination, based on the axis of the Earth's rotation. The declination is the angle of an object north or south of the celestial equator. Declination on the celestial sphere corresponds to latitude on the Earth. The right ascension of an object is defined by the position of a point on the celestial sphere called the vernal equinox. The further an object is east of the vernal equinox, the greater its right ascension.

A coordinate system is a system designed to establish positions with respect to given reference points. The coordinate system consists of one or more reference points, the styles of measurement (linear measurement or angular measurement) from those reference points, and the directions (or axes) in which those measurements will be taken. In astronomy, various coordinate systems are used to precisely define the locations of astronomical objects.

Latitude and longitude are used to locate a certain position on the Earth's surface. The lines of latitude (horizontal) and the lines of longitude (vertical) make up an invisible grid over the earth. Lines of latitude are called parallels. Lines of longitude aren't completely straight (they run from the exact point of the north pole to the exact point of the south pole) so they are called meridians. 0 degrees latitude is the Earth's middle, called the equator. 0 degrees longitude was tricky because there really is no middle of the earth vertically. It was finally agreed that the observatory in Greenwich, U.K. would be 0 degrees longitude due to its significant role in scientific discoveries and creating latitude and longitude. 0 degrees longitude is called the prime meridian.

Latitude and longitude are measured in degrees. One degree is about 69 miles. There are 60 minutes (') in a degree and 60 seconds (") in a minute. These tiny units make GPS's (Global Positioning Systems) much more exact.

There are a few main lines of latitude:the Arctic Circle, the Antarctic Circle, the Tropic of Cancer, and the Tropic of Capricorn. The Antarctic Circle is 66.5 degrees south of the equator and it marks the temperate zone from the Antarctic zone. The Arctic Circle is an exact mirror in the north. The Tropic of Cancer separates the tropics from the temperate zone. It is 23.5 degrees north of the equator. It is mirrored in the south by the Tropic of Capricorn.

Horizontal coordinate system
One of the simplest ways of placing a star on the night sky is the coordinate system based on altitude and azimuth, thus called the Alt-Az or horizontal coordinate system. The reference circles for this system are the horizon and the celestial meridian, both of which may be most easily graphed for a given location using the celestial sphere.

In simplest terms, the altitude is the angle made from the position of the celestial object (e.g. star) to the point nearest it on the horizon. The azimuth is the angle from the northernmost point of the horizon (which is also its intersection with the celestial meridian) to the point on the horizon nearest the celestial object. Usually azimuth is measured eastwards from due north. So east has az=90°, south has az=180°, west has az=270° and north has az=360° (or 0°). An object's altitude and azimuth change as the earth rotates.

Equatorial coordinate system
The equatorial coordinate system is another system that uses two angles to place an object on the sky: right ascension and declination.

Ecliptic coordinate system
The ecliptic coordinate system is based on the ecliptic plane, i.e., the plane which contains our Sun and Earth's average orbit around it, which is tilted at 23°26' from the plane of Earth's equator. The great circle at which this plane intersects the celestial sphere is the ecliptic, and one of the coordinates used in the ecliptic coordinate system, the ecliptic latitude, describes how far an object is to ecliptic north or to ecliptic south of this circle. On this circle lies the point of the vernal equinox (also called the first point of Aries); ecliptic longitude is measured as the angle of an object relative to this point to ecliptic east. Ecliptic latitude is generally indicated by $$\phi$$, whereas ecliptic longitude is usually indicated by $$\lambda$$.

Galactic coordinate system
As a member of the Milky Way Galaxy, we have a clear view of the Milky Way from Earth. Since we are inside the Milky Way, we don't see the galaxy's spiral arms, central bulge and so forth directly as we do for other galaxies. Instead, the Milky Way completely encircles us. We see the Milky Way as a band of faint starlight forming a ring around us on the celestial sphere. The disk of the galaxy forms this ring, and the bulge forms a bright patch in the ring. You can easily see the Milky Way's faint band from a dark, rural location.

Our galaxy defines another useful coordinate system — the galactic coordinate system. This system works just like the others we've discussed. It also uses two coordinates to specify the position of an object on the celestial sphere. The galactic coordinate system first defines a galactic latitude, the angle an object makes with the galactic equator. The galactic equator has been selected to run through the center of the Milky Way's band. The second coordinate is galactic longitude, which is the angular separation of the object from the galaxy's "prime meridian," the great circle that passes through the Galactic center and the galactic poles. The galactic coordinate system is useful for describing an object's position with respect to the galaxy's center. For example, if an object has high galactic latitude, you might expect it to be less obstructed by interstellar dust.

Transformations between coordinate systems
One can use the principles of spherical trigonometry as applied to triangles on the celestial sphere to derive formulas for transforming coordinates in one system to those in another. These formulas generally rely on the spherical law of cosines, known also as the cosine rule for sides. By substituting various angles on the celestial sphere for the angles in the law of cosines and by thereafter applying basic trigonometric identities, most of the formulas necessary for coordinate transformations can be found. The law of cosines is stated thus:
 * $$\cos(c)=\cos(a)\cos(b)+\sin(a)\sin(b)\cos(C)$$

To transform from horizontal to equatorial coordinates, the relevant formulas are as follows:
 * $$Dec=\arcsin\Big(\sin(Alt)\sin(Lat)+\cos(Alt)\cos(Lat)\cos(Az)\Big)$$
 * $$RA=LST-\arccos\left(\frac{\sin(Alt)-\sin(Dec)\sin(Lat)}{\cos(Dec)\cos(Lat)}\right)$$

where $$RA$$ is the right ascension, $$Dec$$ is the declination, $$LST$$ is the local sidereal time, $$Alt$$ is the altitude, $$Az$$ is the azimuth, and $$Lat$$ is the observer's latitude. Using the same symbols and formulas, one can also derive formulas to transform from equatorial to horizontal coordinates:
 * $$Alt=\arcsin\Big(\sin(Dec)\sin(Lat)+\cos(Dec)\cos(Lat)\cos(LST-RA)\Big)$$
 * $$Az=\arccos\left(\frac{\sin(Dec)-\sin(Alt)\sin(Lat)}{\cos(Alt)\cos(Lat)}\right)$$

Transformation from equatorial to ecliptic coordinate systems can similarly be accomplished using the following formulae:
 * $$\phi=\arcsin\Big(\sin(Dec)\cos(\epsilon)-\cos(Dec)\sin(\epsilon)\sin(RA)\Big)$$
 * $$\lambda=\arcsin\left(\frac{\sin(Dec)-\sin(\phi)\cos(\epsilon)}{\cos(\phi)\sin(\epsilon)}\right)=\arctan\left(\frac{\sin(RA)\cos(\epsilon)+\tan(Dec)\sin(\epsilon)}{\cos(RA)}\right)$$

where $$RA$$ is the right ascension, $$Dec$$ is the declination, $$\phi$$ is the ecliptic latitude, $$\lambda$$ is the ecliptic longitude, and $$\epsilon$$ is the tilt of Earth's axis relative to the ecliptic plane. Again, using the same formulas and symbols, new formulas for transforming ecliptic to equatorial coordinate systems can be found:
 * $$Dec=\arcsin\Big(\sin(\phi)\cos(\epsilon)+\cos(\phi)\sin(\epsilon)\sin(\lambda)\Big)$$
 * $$RA=\arcsin\left(\frac{\sin(Dec)\cos(\epsilon)-\sin(\phi)}{\cos(Dec)\sin(\epsilon)}\right)$$

title: General Astronomy/Coordinate Systems


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General Astronomy/Types of Galaxies

Estimates of the number of galaxies in the universe range from 10 billion to over 100 billion. According to Hubble's Law, galaxies are red-shifted. This means that they're moving away from us. Young galaxies are more blue, while old galaxies are more red. As spiral galaxies mature, the center becomes red. The arms are bluish.

The Hubble Sequence
The most common form of classification for galaxies is based on a system which categorises them by their visible structure. This is known as the Hubble Sequence, and was developed by Edwin Hubble in the 1920s. Galaxies are organized in a form resembling a tuning fork, often called the Hubble Tuning Fork Diagram. It is typically drawn with elliptical galaxies on the left, lenticular galaxies in the middle, and two branches of spiral galaxies on the right: one for un-barred spirals, and one for barred spirals. Elliptical galaxies, also known as "early-type" galaxies, have an ellipsoidal form, with a fairly even distribution of stars throughout. They are mostly featureless and have no form of visible disk. Examples of ellipticals include M87, whose black hole was the first to be imaged in high-resolution, and ESO 383-76, which is one of the largest galaxies ever discovered. They are denoted by the letter E, with the number giving the degree of eccentricity: E0 galaxies are nearly spherical, while E7 are greatly elongated.

Lenticular galaxies appear to have a disk-like structure with a central spherical "bulge" projecting from it, but they do not show any spiral structure. They were originally introduced as a theoretical intermediate class between ellipticals and spirals before being confirmed by observations. An example of a lenticulat galaxy is NGC 2787. These are given the class S0.

Spiral galaxies, also known as "late-type" galaxies, have a central "bulge" and an outlying "disk"; the disk is notable for having spiral "arms" within it, centered on the bulge. Sa galaxies have very "tightly wound" arms, while Sc galaxies are very loose spirals. Barred spiral galaxies have a similar sort of spiral structure to spiral galaxies, but instead of emanating from the bulge, the arms project out from the ends of a "bar" running through the bulge, like ribbons on either end of a baton. Again, SBa to SBc refer to how "tightly wound" these arms are. Examples of spiral galaxies include: the Milky Way, our home galaxy; Andromeda (M31), the closest galaxy to us; and the Pinwheel Galaxy (M101).

Finally, there are irregular galaxies, which show no clearly discernable or regular shape. Some examples of these include the Large and Small Magellanic Clouds, which can be seen from the Earth's southern hemisphere. These are given the class Irr.

Links to Galaxy Evolution
Hubble based his classification on photographs of the galaxies through the telescopes of the time. He originally believed that elliptical galaxies were an early form, which might later evolved into spirals; our current understanding suggests that the situation is roughly opposite.

More modern observations of galaxies have given us the following information about these types:
 * Elliptical galaxies are generally fairly low in gas and dust, and are composed mostly of older stars.
 * Spiral galaxies generally have plentiful supplies of gas and dust, and have a broad mix of older and younger stars.
 * Irregular galaxies are fairly rich in gas, dust, and young stars.

From this, astronomers have constructed a theory of galaxy evolution which suggests that ellipticals are, in fact, the result of collisions between spiral and/or irregular galaxies, which strip out much of the gas and dust and randomize the orbits of the stars.

title: General Astronomy/Types of Galaxies


text:
Talk:General Astronomy

I'm not sure the "IRAF" entry under "Tools of Astronomy" was what the person originally outlining the page had in mind. In the normal course of instruction, the principles of light and gravity, as they relate to astronomy, would be discussed in such a section - not the tools for image reduction per se. A section for astronomical techniques could be added, of course. April Follies 04:50, 4 Sep 2004 (UTC)

Cleanup of this Wikibook
I added the RfD to this page, and the subsequent discussion on WB:RFD, because I feel that many of the modules in this Wikibook are much better written and better monitored on Wikipedia. As this current is organized, this Wikibook is a fork of the Wikipedia Astronomy Wikiproject and not coherantly organized into a textbook at all but is instead a Macropedia.

Keep in mind, what I'm proposing is entirely my own idea on how a Wikibook should be organized, and you can certainly argue against what I'm saying here and suggest this is patent nonsense. I am however trying to improve Wikibooks in general one little part at a time.

What we need to start with here is to restart this Wikibook with a formal outline that introduces astrophysics concepts in a chronological order (for teaching... not necessarily the order they were discovered) instead of a bunch of independent modules. Some key sections would include the following:

 * Cosmology - How the universe began and where it may ultimately go
 * History of Astronomy - Kepler, Brahe, Copernicus, Galileo, Newton, Einstein, ect.
 * Philosophical movement from Earth-centered universe to Sun-centered universe to no-center of the Universe.
 * Why we know what we know about stars and planets:
 * H-R Diagrams
 * Stellar Parallax
 * Spectral classifications
 * Distance measurement
 * Planetary probes (Voyager, Cassini, Pioneer, etc.)
 * Basic Newtonian laws of Motion
 * And many more astronomy topics

A much earlier RfD was started about Mercury because it was a blatant copy & paste from a NASA website. In that case, because it was public domain and Wikibooks was a much younger project simply in need of content, the article was allowed to remain. I am now challenging that presumption, and suggesting that this whole Wikibook needs a major cleanup including deletion of many of the current set of modules and essentially "starting over again" but this time to become a real textbook about Astronomy.

Any of the sections on planets that go into deeper detail than the Wikpedia articles shoud be independent Wikibooks in their own right, being added to an Astronomy bookshelf instead. Anything less should stay on Wikipedia, unless it is a clear stub that shows regular progress to becoming its own book.

I'm also going to try and get some support from the Astronomy Wikiproject crew, as they may have some suggestions of their own on this topic. --Rob Horning 14:11, 19 November 2005 (UTC)

 * I agree that this material should be reorganized to more closely resemble a traditional astronomy textbook, but I don't think it makes sense to put cosmology (meaning the complete treatment of cosmology) at the very front. A "you are here" type of chapter seems much more sensible, and that's probably what you have in mind anyway. A lot of cleanup seems to be needed around here. The biggest problems I see are:

 * Is having external links for content good policy? Maybe we can find out whether the author of that material is willing to publish under GFDL. If not, is it better to keep the link, move it to a list, or remove it entirely?

 * Over the past month or so the planets section has been "supplemented" with ephemerides and other tables. These don't seem at all appropriate -- they're way too long and too cryptic for an introductory text. I've gone ahead and removed these. Apologies to whoever put these up... Is there some more appropriate place for them?

 * The organization of the book past the first few chapters should probably be fleshed out.

 * I'll be thinking about this as I have time, which doesn't happen too often. Thanks very much to the earlier contributors, and for your comments, Rob. --Brian Brondel 20:14, 1 January 2006 (UTC)

Transwiki:Astronomy for beginners is now available for merger into this wikibook. Uncle G 04:44, 20 November 2005 (UTC)

renaming chapters of the Astronomy book
Here's my plan:
 * Make up new names for each module, that match the latest Naming_policy, and put them on this Astronomy page. (They will, of course, all be red, since they don't exist yet).
 * Temporarily, every link will be doubled -- one blue, one red.
 * Slowly move each module to a better name.
 * Once all the doubled links turn blue, delete all the old names (that now only point to redirects).

Just letting you know what I'm doing. I hope this makes sense. --70.189.75.148 07:15, 10 January 2006 (UTC)

 * Sounds great. Remember that articles should be moved from the "move" tab at the top of each page, rather than copied and pasted. --Brian Brondel 04:25, 11 January 2006 (UTC)

RfD for Astronomical events
This is just an FYI to anybody involved with this Astronomy Wikibook. I've added a RfD notice to try and decide as a community where to put this sort of content. There is also discussion on Wikisource about this same content that is currently duplicated there. Feedback in both places is encouraged. --Rob Horning 18:19, 23 January 2006 (UTC)

 * Wikisource decided to keep Moon, Ceres, Pallas and Juno, so the proposed deletion is now in the archives.

 * I changed Astronomy to link to Astronomical events instead of our copy. I plan to make links from that Wikisource page to Moon, Ceres, Pallas, and Juno. --Kernigh 02:52, 12 February 2006 (UTC)

Consistency in chapter names
Currently quite a few of the chapter or subchapter names in the table of contents do not coincide with the names on the actual pages. I propose that they be made the same, either by changing the one to coincide with the other, or by combining them into an expanded name in each case. Douglas W. Mitchell (talk) 17:00, 23 August 2010 (UTC)

Amateur astronomer
It seems that the book would benefit from a section about amateur astronomy. Definition and simple guide including how to access available resources, for instance the new "GLObal Robotic-telescopes Intelligent Array" (GLORIA) that will be the first free and open- access network of robotic telescopes of the world. --Panic (discuss • contribs) 18:38, 19 October 2011 (UTC)

Kepler’s third law have a mistake
In astronomy, Kepler’s laws give a description of the motion of planets around the Sun. Kepler's laws are only valid when not affected by the gravity of other planets, however，Kepler’s third law does not follow this restriction. For this reason, It simply has no use at all in our Solar System. Kepler's third law assumes that all planets are not affected by the gravity of other planets and the orbit of every planet is an ellipse with the Sun at one of the two foci.This is not true. If the planet did not affected by the gravity of other planets, then the orbit of every planet is a circle. The orbit of the planet have an ellipse only because affected by the gravity of other planets. , Kepler’s third law, T2/a3/2=K, only good for comets and not for our Solar System, for this mistake we have a new third law as T2/(ab)3/2=K.

What happens to astronauts when they get in those galaxies ? do they go to another real dimension? Bracket Lynch (discuss • contribs) 17:51, 11 December 2019 (UTC)

Fourth law:
In solar system, All planets, no matter their size, their mass, their shape, their radius should follow (ab)3/2/T2 =1,

Where T is Orbit Period, a is the semi-major respect to earth b is the semi-minor respect to earth

Fifth law:
In solar system, every precession of the orbits of planets has different precession with different ellipses. Every different ellipse has its orbital eccentricity between maximum e and 0. And all different ellipses have the same area, include circle of e=0.

For example:
The precession of the orbit of Mercury is 11.83 degree/ century. Every year have different ellipse between e= 0.20563069 and e=0, but every different ellipse or circle has the same area.

Sixth law:
To determine whether it is a planet or not, it is not according their size, their mass, their radius, or their shape, but one must fulfill the fourth law.

Conclusion:
1. Obviously, Pluto does not follow the forth law, therefore, Pluto is not a planet, not even a dwarf planet. It is not because it is small, or other reasons, but because it is not fulfill with the fourth law. Therefore, it is not one of the family.

2. There are two reasons that why Pluto does not belong to the solar system. Pluto may be a comet or half a comet, because

A. Pluto is an alien, may come from other galaxies.

B. Pluto may joint with a planet and a member of the other galaxies.

3. A planet cannot be discriminated because of their size, their mass, their radius, their color, or that they are ugly not round. As long as they fulfill with the fourth law, They are planets. Otherwise they are not planet.

Should General Astronomy allow this editorializing?
The most recent two edits are: https://en.wikibooks.org/w/index.php?title=General_Astronomy&type=revision&diff=3389597&oldid=3348591

I am mostly on Wikiversity, where this would be allowed. Wikipedia would (or should) revert. On Wikibooks, I yield to the community. Also, if Wikibooks wants to consider developing policy on this, let me know. Both Wikibooks, as well as Wikiversity, might benefit from introspection regarding our policies.--Guy vandegrift (discuss • contribs) 13:30, 18 March 2018 (UTC)

 * Since I made the edit I'm interjecting in it's defense. There is no policy in place beyond the requirement for keeping a neutral point of view (that can be tamed in a per project/book basis) in any case I did not consider the edit an editorialization (as shaping the work to reflect a personal opinion) at best it could be considered the inclusion of an overgeneralization (even a Western centric one). I would guess that in most of Africa, large parts of South America and Asia it would not apply but probably those left out would also not be using Wikibooks. On the other hand the minority of people that deal every day with astronomic concerns may have a different perception of (even aspiration for) the relevance astronomy has in today's society.
 * In any case feel free to balance the edit as you wish, my intention was only to add the interesting video link and contextualize it into the content including a reflection of the reality most of us that write and read wikibooks share (my only objection would be to a removal of the video link without proper argumentation/defense). --Panic (discuss • contribs) 22:10, 18 March 2018 (UTC)
 * I actually agree with both assertions, namely that there is a decrease in interest in the nature of the universie, as well that it is "sad". I will not change or challenge the edit.  As far as I am concerned, it was a good edit that can stay.  I just thought the community should be notified. --Guy vandegrift (discuss • contribs) 02:01, 20 March 2018 (UTC)

title: Talk:General Astronomy


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File:Earthtilt.jpg

Cartoon of the tilt of the Earth's poles with respect to the ecliptic

title: File:Earthtilt.jpg


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General Astronomy/Yearly Motions

Why do we have seasons? A little thought will suggest that it can't have much to do with the Earth's distance from the sun, as that would affect the Southern and Northern Hemispheres at the same time. (In fact, the Earth is slightly nearer to the sun around December than at other times of the year.) Why, then are there seasons?

Every year the Earth completes one orbit of the Sun. We see this observe the effect as the change of the seasons and the movement of the constellations. Over the course of a year, the Sun moves through a great circle on the celestial sphere, tracing out the same path year after year. This path is called the ecliptic. The ecliptic is not only the path of the Sun in the sky, it also marks the plane of the Earth's orbit of the Sun. The planets orbit the Sun in different planes but near to the ecliptic.

The axis of the Earth's rotation is tilted by 23½° with respect to the plane of the ecliptic. Globes are typically built with an inclined rotation axis. The 23½° North latitude is marked as the Tropic of Cancer and the 23½° South latitude is marked as the Tropic of Capricorn. In the Northern Hemisphere, the Sun will pass directly over head only between June 20 and 22th along the Tropic of Cancer. That day is called the day of the summer maximum or Solstice in the Northern Hemisphere. In the Southern Hemisphere, the Sun will pass directly over head only once between December 20 and 23rd along the Tropic of Capricorn. Anywhere between the Tropic of Cancer and the Tropic of Capricorn, the Sun will pass directly overhead at least twice during the year, but the Sun will never pass overhead for people living outside the tropics. Within the Tropics, over the course of a year, the Sun's position in the sky changes, beginning in the southern sky about December 21, moving to the northern sky in mid-year, and ending the year back in the southern sky.

The tilt of Earth's rotation axis causes a 23½° tilt of the great circle of the ecliptic with respect to the Earth's equator. The ecliptic and the equator intersect at two points, but are otherwise separated by up to 23½°. When the sun lies at one of the intersections, it is directly overhead somewhere on the equator. This occurs at the equinox, and the points on the sky where the equinox intersects the equator are also called equinoxes. Once every year, the Sun passes through the equator going north. This happens in late March — the "vernal" or "spring" equinox. The "autumnal" equinox occurs when the Sun passes through the equator in late September.

On the equinox days, the day and night are equally long. This is the origin of the name equinox, which is from Latin for "equal night." On the day of the equinox, the Sun rises due east and sets due west. It doesn't rise to directly overhead, though, except for observers on the Equator. The equinoxes are the only days of the year that have twelve hours of daylight and twelve hours of dark. After the vernal equinox, moving into Northern summertime, the Sun begins rising in the northeast and sets in the northwest. Days in the Northern Hemisphere become longer, while days in the Southern Hemisphere become shorter.

The points at which the Sun is at its greatest distance from the equator are called the solstices. The solstices mark the longest and shortest day of the year. The longest day of the year is the summer solstice and the shortest day is the winter solstice. In the Northern Hemisphere, the summer solstice occurs when the Sun is farthest north, while the winter solstice occurs at the Sun's southernmost point. In the Southern Hemisphere, the solstices are reversed.

Viewed from space, we see that the Earth's tilt changes the exposure of different parts of the Earth to the Sun. Observers in the Northern Hemisphere will see the Sun at its lowest position in the southern sky, about December 21. They see it this way because the Southern Hemisphere is tilted towards the Sun and the Northern Hemisphere is tilted away. About June 22, the situation is reversed, with the Northern Hemisphere pointed toward the Sun, and the Sun will be in its extreme high point in the sky at solar noon. For an observer in the Southern Hemisphere, the Sun will appear at its lowest point in the sky in the north, about June 22, while the Sun will appear at its high point in the sky about December 21. One effect of this phenomenon is that during the months of Northern Hemisphere summer, the North Pole will be able to receive sunlight twenty-four hours a day. The Sun will remain visible through much of the autumn, passing below the horizon at the autumnal equinox. As winter sets in at the North Pole, the Sun will not be seen for six months, while that portion of the Earth is tilted away from the Sun.

As one moves toward the Earth's equator from either pole, this effect becomes less severe. The nearer one is to the equator, the less difference there will be between the number of hours of illumination and night hours. At the equator, there's practically no difference between the length of day all through the year.

Clearly, the annual motion of the Earth around the Sun is the cause of Earth's seasons. What effect gives rise to this seasonal change is less obvious. At first glance, one might think that winter occurs when the Earth is farther from the Sun. If we realize the Northern and Southern Hemispheres have winter at different times of year, we see that this can't be right. Also, the Earth's orbit is very nearly circular. The change in the Earth's orbital distance is much too small to have a noticeable effect on Earth's climate.

Certainly the length of time each day during which sunlight falls on a particular location has a great deal to do with the seasonal changes in temperature. However, another effect less obvious, but more influential is the angle at which the sunlight hits a region. At the equator, there is little difference throughout the year as the Sun varies by 23.5 degrees on either side of the vertical. The length of the ray's path on Dec 21 at solar noon is increased by a factor of only 1.1 from a direct vertical path and the reduction of the sunlight is small. The more direct radiation gives the maximum amount of heat and energy to the earth where it falls, and therefore these areas will receive the most warmth. Away from the equator, however, the Earth's tilt means that sunlight is not received so directly and a greater amount of the Sun's energy is blocked by the longer path it takes through the atmosphere. At 50 degrees north latitude, the path the Sun's rays travel through the atmosphere on Dec 21, at solar noon, will be increased by a factor of 3.5 from a direct vertical path. In general, the rays will come at an angle that depends on the time of day, the latitude of the region from the equator, and the position of Earth in its orbit.

The constellations in the ecliptic, the zodiac, have a long history in the tradition of astrology. In most newspapers, you can read a (completely unscientific) prediction of your future or some personal advice, specific to your birthday. Each entry is associated with one of the constellations of the zodiac and a range of birth dates. In the tradition of astrology, the constellation the Sun occupied on your birthday, your "sign," reveals information about your personality and your future.

Interestingly, the dates given for each constellation in the newspaper don't match the Sun's position in the sky for those dates. There is a mismatch between the date in the newspaper and the real position of the Sun of a little more than a month. The mismatch appears because the dates corresponding to each sign were set thousands of years ago. Over the course of thousands of years, the Earth "wobbles" on its axis, causing the calendar and the positions of the stars in the sky to shift. This wobble is caused by the pull on the equator by the sun and moon, and is called precession. It affects the positions of all the constellations with respect to the equinoxes and the pole.

The precession of the Earth is like the movement of a top. If you spin a top with the axis tilted, the axis will slowly rotate as the top spins. Likewise, the Earth's axis remains tilted at 23½°, but the orientation of this tilt changes over the course of thousands of years.

Since precession changes the direction in which Earth's pole points, it also changes which star is the North Star, if any. Earlier, we quoted Shakespeare, who referenced Polaris in Julius Caesar, describing it as the northern star. Strictly, this would be incorrect. Polaris was not "fixed" in the sky in Julius Caesar's time because Earth's axis was pointed differently, toward the Big Dipper.

Precession is a slow drift, and a difficult motion to detect. The motion of the stars from precession only becomes noticeable to the unaided eye after many, many years of careful observation, although it becomes very quickly noticeable through a telescope. The Greek astronomer Hipparchus was the first to measure the precession by comparing his own observations to observations collected a century and a half before.

Precession changes the position of the Earth in its orbit for the solstices and the equinoxes. As the Earth's axis turns over, the moment when it points most closely towards the Sun changes, and so the seasons change. If a calendar didn't account for this, the seasons would drift as the axis precessed. Eventually, the Northern Hemisphere would be cold in July and warm in January, and the Southern Hemisphere would have warm July weather and cold January weather. The calendar takes the extra motion of precession into account by using the tropical year as its basis. The year as we usually define it is a sidereal year, the time it takes for the Earth to make one orbit around the Sun. In one year, as we usually measure it, the Earth really completes a little more than a full orbit around the Sun. During a sidereal year, the Sun moves fully around the sky and back into the same position with respect to the stars. In a tropical year, the Sun goes from the Vernal Equinox, around the sky, and back to the Vernal Equinox again. During this time, the equinox has shifted slightly in its position, so that a tropical year is a bit shorter than a sidereal year.

It's easy to identify the progression of the calendar if you take careful notice of the sky. Next time you see sunrise or sunset, take notice of whether the Sun is setting due west or just north or south of west. Many ancient cultures watched the motion of the Sun carefully and over long periods of time. Using simple techniques and tools, they were able to measure periods like the length of a year very accurately. Ancient people who took notice of celestial motion would have found that the summer solstice occurred every 365 days. They would also notice that the solstice was delayed an extra day every four years. This is the reason for the leap year in the modern calendar. The delay occurs because the length of the year is a little more than 365 days — closer to 365¼ days long. By taking some simple observations over a period of a few years, it is possible to measure the length of a year to surprising accuracy using this technique.

Solar calendars have been used throughout history. The ancient Babylonians thought the year had only 360 days, and made their calendar accordingly. The Islamic calendar is lunar, and is 11 (1/2) days different than the solar calendar. The Hebrew calendar is lunisolar.

Our modern calendar is handed down to us from the Ancient Roman civilization. The calendar took its first mature form as the Julian calendar, almost exactly the same as the one used today. It had 365 days in a year, with a 366-day leap year every four years. In the Julian calendar, years divisible by 4 — such as 1992, 1996, and 2008 — are leap years. This gave the Julian calendar an average of 365¼ days per year, which is very close to the true 365.2422 day length for a tropical year.

Although the drift of the Julian calendar is slow, the error in the calendar had accumulated enough by the sixteenth century that the Catholic Church became concerned about the drift's effect on the date of the celebration of Easter. The Italian chronologer Aloisius Lilius invented modifications to the Julian calendar to correct the difference. Pope Gregory XI instituted the new calendar, now named the Gregorian calendar, in the year 1582.

The Gregorian calendar was identical to the Julian calendar except that the leap year was skipped on years not divisible by 400. In the years 1600, 2000, and 2400, there would be a leap year in the Gregorian calendar, but not 1800, 1900, or 2100. This produced a year of average length 365.2425 days, much closer to the correct value than the Julian calendar. The Gregorian calendar accumulates only 3 days of error over 10,000 years.

Discussion questions
1) On the date of the summer solstice, the sun is overhead on the Tropic of Cancer, and on the date of the winter solstice the sun is overhead on the Tropic of Capricorn. Draw a quick sketch that shows the relative positions of the sun and the earth on those dates.

2) On the date when the sun is overhead on the Tropic of Capricorn, the sun is actually located in the constellation of Sagittarius. So why did the Greeks name Tropic of Capricorn the Tropic of Capricorn instead of the Tropic of Sagittarius?

title: General Astronomy/Yearly Motions


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General Astronomy/Phases of the Moon

Like the stars and planets, the Moon doesn't stay fixed in the sky but slowly moves as the Earth rotates and as the Moon moves through its orbit about the Earth. To someone taking a casual glance at the Moon, it seems as fixed as the stars. But observation of either the Moon or the stars over a period of several hours will reveal their diurnal (daily) motion across the sky. The Moon rises and sets each day. An observer who watches the Moon over the course of many days will notice the Moon moving not only with the stars, but among them. Every month, the Moon completes one fewer pass across the sky than the stars have completed. We see this because of the Moon's orbit about the Earth. As the Moon progresses through its orbit, its rising and setting times change. Each day, the Moon rises and sets fifty minutes later than the day before.

The moon usually takes 27 days to rotate once on its axis. So any place on the surface of the moon experiences about 13 days of sunlight, followed by 13 days of darkness. Temperatures on the Moon range from -153 C at night to 253 C during the day. For example if you were standing on the surface of the moon during sunlight hours it would be blazing hot. When the sun goes down, the temperature automatically drop 250 degrees in just a matter of moments. Furthermore, there are craters around the North and South poles of the moon which never seen the sunlight. These dark places would always be as cool as -153 C. However, there are nearby mountain peaks that are covered in continuous sunlight, and would always be hot.

The "dividing line" between the light and dark halves of the globe is called the terminator, as it terminates the area of darkness (and also that of daylight).

Typically, one-half of the Moon will be lit up by the Sun, while the half facing away from the Sun remains dark. (The only exception occurs during a lunar eclipse, when the Earth blocks the light falling on the lit side of the Moon.) The part illuminated by the Sun is not, it should be emphasized, always the same portion of the Moon's surface! Like the Earth, the Moon turns on its axis, exposing different areas at different times. In combination with the orbital revolution of the Moon around the Earth, this phenomenon creates the phases of the Moon as seen from Earth. The phrase "Dark side of the Moon" arose before the age of artificial satellites and the back side of the Moon could not be observed. Hence, the that one side was unknown or "dark".

The tilt of the moon’s spin axis is only 1.54 degrees and as a result, lunar seasons are barely noticeable in most locations on the Moon. However, at the North and South poles, the height of the sun above the horizon varies by more than 3 degrees over the course of the year. In other words, it affects the percentage of sunlit regions and surface temperatures at the poles. Furthermore, the coldest areas are located in doubly shadowed regions inside small craters, in which they are located within the permanently shadowed regions of larger craters. Temperatures are as low as 35K (-238 C or -397 F) in these areas, even at noon on the warmest day of the year.

Some half of the Moon is always illuminated but the fraction of the illuminated part or the Moon's phases directly depend on the relative positions of the Earth, Moon, and Sun. Simply put, it's a matter of how much of the daylight side of the Moon we can see from our current viewing angle. The phase will depend on how much of the side facing toward us is illuminated at any given time. The sketch below illustrates the phases of the moon for various Earth-Moon-Sun positions (the Sun is presumed to be off of the diagram to the right):

Next to each "Moon" is a black-and-white sketch of the phase as it would be seen from Earth when the Moon is in that position. When the Moon is between the Earth and the Sun, the sunlit side of the Moon is facing completely away from us, and therefore we have the dark "New Moon". When the Moon reaches the other side of the Earth, the sunlit side will be fully toward us, and we have the "Full Moon". As the Moon moves from New to Full and the sunlit side grows increasingly large, we say the Moon is waxing; as we see less, in the decline from Full to New Moon, we say it is waning.

Midway between the Full Moon and New Moon, half of the sunlit side of the Moon is visible from the Earth. Because a half of the half illuminated Moon can be seen, this is referred to as a "quarter Moon". When the Moon is waxing and reaches this position, it's called the "first quarter Moon"; when waning, the "third quarter Moon." When less than a quarter-moon is visible, it's referred to as a "crescent Moon" - waxing crescent or waning crescent, as appropriate. When more than a quarter-moon is visible, it's referred to as a "gibbous moon", again, waxing or waning.

The Moon's orbit and rotation speed is just such that the Moon always shows the same side to Earth, aside from only a slight "wobble." The pattern of markings on the side facing Earth is very familiar in history and culture. Western society has long imagined a face in the markings — the "Man in the Moon." Other cultures have seen a woman, a rabbit, a frog or other creatures. The Moon always shows this same face to Earth because its rotation is "locked" with its orbit, for reasons we will see later, when we discuss gravity. More precisely, the time it takes for the Moon to complete a trip in its orbit is the same as the time it takes for the Moon to rotate once around its axis. Because we see the Moon moving around us, it appears as though the Moon isn't turning at all.

If you stood on the Moon and looked up at Earth in the sky, you would see that it never rises, never sets, and never moves in the sky at all. Imagine, for example, standing at the middle of the face of the Moon that we see. From there, the Earth would always remain straight overhead. If you stood at the edge of the face we see from Earth — the "limb" — you would always see the Earth on your horizon.

Up to now, we have considered the time for the Moon to complete one orbit around the Earth to be the same as the time for it to pass once through its series of phases, but this is not quite right. The Moon's phase at a particular point in its orbit changes as the Earth goes around the Sun. Once the Earth has gone halfway around the Sun, the position of the Moon for a given phase has also moved halfway around the orbit, since the Sun is on the opposite side. Thus, it takes a little longer for the Moon to go through its phases than it does for it to go through its orbit about the Earth.

Suppose a full moon marks the beginning of both the period of the orbit of the Moon about the Earth and the period of the orbit of the Earth about the Sun. At the time of full Moon, the Sun, Earth, and Moon are aligned. Once the Moon returns to that position in its orbit, the Earth has moved a little around the Sun. Now, the Moon is not aligned with the Earth and the Sun. It takes about two days before the Moon has moved back into alignment with the Earth and Sun line (synodic month). The time for the Moon to complete an orbit, called a sidereal month, is about 27 days and 8 hours. The time to move through its phases, a synodic month, is about 29 days and 12 hours.

title: General Astronomy/Phases of the Moon


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What You Should Know About Medicines/Tolerance

In medicine, tolerance is the process of the body needing more of a drug to gain the same result.

This effect is especially pronounced in opiate drugs, such as heroin, and indeed any drug which changes the brain.


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What You Should Know About Medicines/Euphoria

Euphoria is the state of being in a high.

It is usually experienced when taking mind-altering drugs such as ecstasy and marijuana.


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Introduction to Psychology/Child and Adolescent Psychology/Childhood and the Law

Children's rights have only attracted attention relatively late in human history; the first awareness came in the 19th century in regard to child labor. The United Nations adopted a convention about The Rights of the Child in 1989 (significantly, before and since, the only convention to be adopted universally), which has encouraged lawyers and others interested in children's rights to contribute to the debate and give their knowledge and interest.


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User talk:144.132.180.182

Please refrain from adding spaces between characters, as this is not the standard typography of written Chinese. --Taoster

title: User talk:144.132.180.182


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Instructional Technology/Hybrid Format Courses

What is a Hybrid Course
"Hybrid" is the name commonly used nationwide to describe courses that combine face-to-face classroom instruction with computer-based learning. Hybrid courses move a significant part of course learning online and, as a result, reduce the amount of classroom seat time. The goal of Hybrid courses is to join the best features of in-class teaching with the best features of online learning to promote active independent learning and reduce class seat time.

Hybrid Course Advantages
Hybrid courses offer a number of advantages over face-to face teaching and totally online courses. Instructors from other colleges have reported that the hybrid course model allows them to accomplish course learning objectives more successfully than traditional courses do. Some faculty have noted increased interaction and contact from many of their students and between the students and themselves. Studies have shown that students and instructors liked the greater convenience afforded by the hybrid course model, which allows coursework to be scheduled flexibly and erases the time spent commuting and finding parking. Time flexibility was overwhelmingly the most popular feature of the hybrid courses for the students.

 * Convenience: coursework accommodates students’ schedules, commuting time is decreased. Interaction: Hybrid instructors report increased interaction and contact among students and between the instructor and the students.

 * Flexibility: instructors can accomplish certain learning objectives more successfully than in traditional courses because of the flexibility of the Hybrid model. Rachel Spilka explains this point in her article, Approximately "Real World" Learning with the Hybrid Model Teaching With Technology Today, March 20, 2002.
 * Increased learning: faculty almost universally report their students learn more in the Hybrid format than they do in traditional class sections. Instructors report that students write better papers, perform better on exams, produce higher quality projects, and are capable of more meaningful discussions on course material.

 * Increased retention: data collected from the University of Central Florida (UCF) shows student retention in Hybrid courses is better than retention in totally online courses and equivalent to that of face-to-face courses.

Other references: Hybrid Teaching Seeks to End the Divide Between Traditional and Online Instructionarticle by Jeffrey R. Young, Chronicle of Higher Education, March 22, 2002.

Hybrid Courses are Best column by David G. Brown, Vice President, Wake Forrest University in Syllabus: New Dimensions in Education Technology, August 2001.

Hybrid Course Challenges
Instructors and Institutions planning to develop Hybrid courses will face some challenges, which include: Creating a formal faculty development program for teaching Hybrid courses Without preparation most instructors will simply transfer traditional course content to the web. Thus, the first essential step is to create a formal Hybrid Course Faculty Development Program. Faculty need to learn how to redesign their courses and how to teach well online.

We offer the University of Wisconsin-Milwaukee Learning Technology Center’s Model Program as a blueprint for developing your own faculty development program. http://www.uwm.edu/Dept/LTC/model-program.html Allocating the necessary time for instructors to redesign traditional courses into Hybrids

Course redesign is time-consuming. Faculty need sufficient time to develop their new courses and enhance their instructional skills. This is especially true for first-time Hybrid course teachers. A six-month lead-time for preparation, redesign and course development is the minimal time needed by most instructors to create their first Hybrid courses. Preparing students to learn effectively in Hybrid courses

Just as faculty need preparation to teach Hybrid courses, students need preparation to learn in Hybrid courses! Students have some difficulty grasping the “Hybrid” learning concept. They are delighted by its convenience but are affronted by their perception of its additional work. We learned that students do not equate time spent in lectures as “work” but DO perceive the online assignments that replace the lectures as “work”. Students need instructors to explain (repeatedly) the Hybrid course concept and why the instructor has chosen this model. Students also need time management skills to succeed in a Hybrid course. See following site for student issues regarding Hybrids:  http://www.uwm.edu/Dept/LTC/student-issues.html

Return to Instructional Technology.


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User talk:Jeandré~enwikibooks

Hello Jeandré, and welcome! You might want to visit Textbook planning and the first few sections of the Staff lounge, to get a sense of how books are built. Sj 22:47, 4 Sep 2004 (UTC)

Wikijunior Solar System Proofreading
Thanks for your help on Wikijunior Solar System! I see you are more active at wikipedia, so I have written you a message there. --SV Resolution 13:32, 25 September 2005 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Jeandré. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Jeandré~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 23:19, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 05:04, 19 April 2015 (UTC)

title: User talk:Jeandré~enwikibooks


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User talk:Lobster

Hello lobster, and welcome! You have been pretty active recently; you might want to visit Textbook planning and the first few sections of the Staff lounge, to get a sense of how books are built. Sj 22:49, 4 Sep 2004 (UTC)

Wikiversity
I saw your name on the Wikiversity participant's list, you may be very experienced in mathematics already, but I'm trying out instructing a Calculus course if you're interested, go to Wikiveristy, check out the mathematics department, pure mathematics, and in the course list is included Calculus. Fephisto 22:53, 9 July 2006 (UTC)

from Lob
Thanks very much - will check out the links :-)

Hello lobster, please don't modify my WikiSci pages... --Bootedcat 13:22, 18 Sep 2004 (UTC)

Using Firefox
Nice page - but was dissapointed that the plug-ins do not work with version 1 of firefox - here is hoping they will soon - Lobster

 * I'm not sure why they created it; there are tons of other helpful pages out there. But I will help contribute.  Yes, I installed Firefox 1.0PR just a few minutes ago and I am very disappointed that some of my favorite extensions do not work yet.  I should have waited.  :-) - Omegatron 21:25, 18 Sep 2004 (UTC)

 * sorry not quite sure what I am doing but hopte this comment gets to you :-)
 * I think the XUL (type of XML) will be updated soon and then the plug ins will work - but at the mo it is not working - here is hoping

 * Foxy Lobster
 * Foxy Lobster

 * Ah. Yeah, some of the extensions just need to be updated again, I guess.  I will just have to wait around for them...  But I should have waited to upgrade until I knew everything would work.  I was impatient, and I get what I deserve.  :-)

 * By the way, you can sign messages by typing ~ if you didn't know.

 * (makes it easier to reply to you.) - Omegatron 01:29, 19 Sep 2004 (UTC)

vfd tag removal
If you think a page shouldn't be deleted, please comment at Votes for deletion. Simply removing the vfd tag will not stop the deletion process, and is considered vandalism. Gentgeen 09:47, 7 Oct 2004 (UTC)

Many thanks for the info Genteen was unaware of that :-) Lobster 10:08, 9 Oct 2004 (UTC)

Voting
Please log in before voting. Did you really vote for the featured wikibook? 12:24, 17 Jan 2005 (UTC)

Book of the month vote confirmation
Please go to Book of the month voting for February 2005 to confirm your vote. A vote was made in your name by a user that was not logged in. r3m0t (cont) (talk) 17:24, 25 Jan 2005 (UTC)

Freeware
I apreciate your work on Freeware, especialy the tables/graphics. Maybe you would like to comment on my new project, Wikisolutions and maybe contribute. It should be nice to have tables and pictures for solutions, and make it to look nicer. Moa3333 21:45, 18 Jun 2005 (UTC)

Copyright problem with Image:Alchemy1.jpg
--Derbeth 10:26, 11 October 2005 (UTC)

Image:Nasrudin3.jpg
It seems that you have not edited Wikibooks since 2004. However, if you see this, could you please add copyright information to Image:Nasrudin3.jpg?

I added a message to Image:Nasrudin3.jpg that contains a link to a page about how to add copyright information. --Kernigh 20:42, 30 December 2005 (UTC)

Image:Chinarose.jpg
This notice appears on the referenced image: To the uploader: Please clarify the copyright status of this image. If you indeed wished it to be released under the GFDL please replace with  by editing the image description page. Alternatively you can choose a different image copyright tag, or arrange for the image to be deleted. See Category:Presumed GFDL images for more information about these images.

title: User talk:Lobster


text:
User talk:Booyabazooka~enwikibooks

I will not quickly notice any messages here; if you want a timely reply, drop me a note at English Wikipedia: Booyabazooka (talk).

Hello Booya!, and welcome. You might want to visit Textbook planning and the first few sections of the Staff lounge to get a sense of how books are built. Cheers, Sj 22:49, 4 Sep 2004 (UTC)

Algorithm_implementation/Search/Binary_search
I see that you do Python contributions for Algorithm implementation. So could you fix Algorithm_implementation/Search/Binary_search? My ranting where done mostly in the hope that some Python contributer fixes the code and other language contributors pick up the idea of "test drivers". The Algorithms book actualy demands that within its "Guidelines for Contributors" ("Implementations should be tested well and include test cases.").

I suspect - from my little Python knowlede - that the last line where not copied and

center = left + (right - left) / 2;

might do the trick. But that would untested.

--Krischik T 07:01, 3 July 2006 (UTC)

 * Unfortunately, no — I've transwikied some code, but the only contribution I've made personally has been a Java heapsort (tested!). I'm not yet familiar with Python.  The current state of the book is rather embarrassing; as I've mentioned, right now it's much more of a code dump than a book.  Hopefully I'll get around to putting some serious effort into this, or find some recruits to work on it, which will include code testing. ~ Booya Bazooka 06:58, 4 July 2006 (UTC)

Your account will be renamed
Hello,

The developer team at Wikimedia is making some changes to how accounts work, as part of our on-going efforts to provide new and better tools for our users like cross-wiki notifications. These changes will mean you have the same account name everywhere. This will let us give you new features that will help you edit and discuss better, and allow more flexible user permissions for tools. One of the side-effects of this is that user accounts will now have to be unique across all 900 Wikimedia wikis. See the announcement for more information.

Unfortunately, your account clashes with another account also called Booyabazooka. To make sure that both of you can use all Wikimedia projects in future, we have reserved the name Booyabazooka~enwikibooks that only you will have. If you like it, you don't have to do anything. If you do not like it, you can pick out a different name.

Your account will still work as before, and you will be credited for all your edits made so far, but you will have to use the new account name when you log in.

Sorry for the inconvenience.

Yours, Keegan Peterzell Community Liaison, Wikimedia Foundation 22:59, 17 March 2015 (UTC)

Renamed
 This account has been renamed as part of single-user login finalisation. If you own this account you can |log in using your previous username and password for more information. If you do not like this account's new name, you can choose your own using this form after logging in: . -- Keegan (WMF) (talk) 04:41, 19 April 2015 (UTC)

title: User talk:Booyabazooka~enwikibooks


text:
User talk:April Follies

Hello April and welcome! Thanks for all the cartoons... you might want to visit Textbook planning and the first few sections of the Staff lounge (though I bet you've seen it already), to get a sense of how books are built. Sj 22:51, 4 Sep 2004 (UTC)

Thanks, I have indeed looked at those pages. I'm trying to keep things in line with the WikiBooks formats, but guidance from the experienced contributors is always quite welcome. April Follies 17:09, 9 Sep 2004 (UTC)

Pictures
As you can see at the top of this page, "All unlicensed images uploaded to wikibooks before November 1, 2006 will soon be deleted." You have uploaded images and some of them are untagged. You can see them Follies&grouped= here. Please review them and add appropriate tags. If you have any questions, feel free to ask me. --Think Fast 04:23, 13 November 2006 (UTC)

title: User talk:April Follies


text:
Talk:Irish

Untitled
For discussion of lesson content and structure please visit Irish/Lesson Plan and its talk page. --Chapka (discuss • contribs) 19:01, 9 September 2020 (UTC)

Next Steps (as of 2020)
I'd like to take the core content here and rework it into a more organized set of lessons and better integration of lessons and grammar, with a goal of A1 proficiency to start with. It looks like there hasn't been a lot of activity here in a few years, but is anyone else interested in working on this?

Chapka (discuss • contribs) 15:37, 7 June 2020 (UTC)

 * I have undone some of your changes to the intro section and replaced it with a shortened version of the previous intro. You removed what I thought was a preety good overview (am willing to hear criticism of it) of the language with what felt like a diatribe against the fact that some people call it Gaelic. I have shortened it in case part of the intent was to be shorter and more welcoming. Though really it would be more useful to continue writing new lessons than revamping the intro page. Dalta (discuss • contribs) 23:20, 8 April 2021 (UTC)

title: Talk:Irish


text:
User:Drstuey

REDIRECT w:User:Drstuey

title: User:Drstuey


text:
Lisp Programming/Beginning Lisp

Lisp syntax is very simple and easy to understand. A list is a series of atoms surrounded by parentheses, and the first atom of a list is a function. Any atoms after the first are parameters of the function. An example Lisp expression to add the numbers 1 and 2 together might look like this: (+ 1 2) As you can see, the expression is a list. The first atom is +, which is also a function to be evaluated. 1 and 2 are the parameters of the + function.

You can also use a list as a parameter of a function like this, which adds the numbers 1 and 2 together, but somewhat more fancily: (+ 1 (+ 1 1)) In this example, the second parameter of the + function is a list. The first atom is a function: +. So the inner list is evaluated to two (1+1=2), and then that result is used as the second parameter of the outer list, which then gives the result 3.

There are of course many other functions in Lisp. Some of the most basic are these: +, -, /, *, quote, set, and cons. It should be obvious what the +, -, *, and / functions do and how they work.

The quote function returns its first argument, unevaluated. This is useful for passing a form (expression) to a function, without first evaluating that form (expression). (quote (param1 param2)) would return (param1 param2)

quote can also be abbreviated as '. ' goes "outside" the list that it acts on. So '(param1 param2) would return (param1 param2) just like in the first example.

The cons function constructs a list by adding an item to a list. Adding an item to the empty list ' creates a new list. (cons 1 ') returns (1)

(cons 1 (cons 2 (cons 3 '))) returns (1 2 3) Many of the attributes of Lisp are due to the fact that lists are constructed of conses.

Variables
In Lisp, there are several ways to set a variable. Here are the most common.

Setq sets a variable to a given value. If the variable doesn't exist, then it is created. All variables created with setq are global. Setq works like this: (setq variable-name )

An example bit o' code using setq would be this: (setq camel "I am a camel!") (print camel) Which should print "I am a camel!" when it executes.

title: Lisp Programming/Beginning Lisp


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Category:Vegan recipes

These recipes contain no animal products of any sort. See the vegan cuisine section for more info.

es:Categoría:Vegana

title: Category:Vegan recipes


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Category:Vegetarian recipes

Recipes which are prepared according to a vegetarian diet.

es:Categoría:Vegetariana it:Categoria:Ricette vegetariane

title: Category:Vegetarian recipes


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Category:Recipes by diet

Recipes organized by diet.

es:Categoría:Tipos de regímenes

title: Category:Recipes by diet


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Category:Cookbook

This is the parent category for the Cookbook.

__HIDDENCAT__ bg:Категория:Готварска книга da:Kategori:WikiKogebogen de:Kategorie:Kochbuch es:Categoría:Artes culinarias fi:Luokka:Keittokirja fr:Catégorie:Cuisine gl:Categoría:Cociña hy:Կատեգորիա:Եփութուխ it:Categoria:Libro di cucina ja:Category:料理本 ko:분류:요리 nl:Categorie:Kookboek pl:Kategoria:Książka kucharska sr:Категорија:Кувар sv:Kategori:Kokboken th:หมวดหมู่:ตำราอาหาร

title: Category:Cookbook


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Category:Recipes by origin

Recipes organized by national or ethnic origin.

de:Kategorie:Kochbuch/ Rezepte nach Land es:Categoría:Zonas geográficas fr:Catégorie:Recettes par origine id:Kategori:Resep menurut negara it:Categoria:Ricette per provenienza ko:분류:나라별 요리 nl:Categorie:Nationale en etnische keukens pt:Categoria:Culinária por país sv:Kategori:Recept efter ursprung

title: Category:Recipes by origin


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Category:Recipes

Welcome to the Wikibooks Cookbook alphabetical index of recipes. To request that a recipe be added to the cookbook, please see Cookbook:Requested Recipes.

''This is an automatically generated category. Please do not add recipes here by hand.''

de:Kategorie:Kochbuch/ Alle Rezepte es:Categoría:Recetas fa:رده:کتاب آشپزی fr:Catégorie:Recettes de cuisine gl:Categoría:Receitas hy:Կատեգորիա:Բաղադրատոմսեր id:Kategori:Resep is:Flokkur:Uppskriftir it:Categoria:Ricette lt:Kategorija:Receptai ms:Kategori:Resipi nl:Categorie:Recept no:Kategori:Oppskrifter oc:Categoria:Recèptas ru:Категория:Рецепты fi:Luokka:Keittokirja sv:Kategori:Recept uk:Категорія:Рецепти

title: Category:Recipes


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Category:Breakfast recipes

Recipes for breakfast foods.

title: Category:Breakfast recipes


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Category:Holiday recipes

Recipes served on holidays.

title: Category:Holiday recipes


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Category:African recipes

Recipes from Africa.

title: Category:African recipes


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Category:South African recipes

Recipes from South Africa

title: Category:South African recipes


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Category:Asian recipes

Recipes from Asia.

fr:Catégorie:Cuisine d'Asie

title: Category:Asian recipes


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Category:East Asian recipes

Recipes from East Asia.

title: Category:East Asian recipes


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Category:Chinese recipes

Recipes from China.

ko:분류:중국 요리

title: Category:Chinese recipes


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Category:Indonesian recipes

Recipes from Indonesia.

id:Kategori:Resep dari Indonesia

title: Category:Indonesian recipes


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Category:Japanese recipes

Recipes from Japan.

id:Kategori:Resep dari Jepang ko:분류:일본 요리

title: Category:Japanese recipes


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Category:Korean recipes

Recipes from Korea.

ko:분류:한국 요리

title: Category:Korean recipes


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Category:Vietnamese recipes

Recipes from Vietnam.

ko:분류:베트남 요리

title: Category:Vietnamese recipes


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Category:Thai recipes

Recipes from Thailand.

nl:Categorie:Thaise keuken

title: Category:Thai recipes


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Category:European recipes

Recipes from Europe.

de:Kategorie:Kochbuch/ Europäische Küche fr:Catégorie:Cuisine d'Europe nl:Categorie:Nationale en etnische keukens pl:Kategoria:Kuchnia europejska

title: Category:European recipes


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Category:Belgian recipes

Recipes from Belgium.

nl:Categorie:Belgische keuken

title: Category:Belgian recipes


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Category:Danish recipes

Recipes from Denmark.

nl:Categorie:Deense keuken

title: Category:Danish recipes


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Category:French recipes

Recipes from France.

Related Categories
The following related category may be of interest.

L

Louisiana_Creole_cuisine

de:Kategorie:Kochbuch/ Französische Küche es:Categoría:Gastronomía de Francia fr:Catégorie:Cuisine française it:Categoria:Ricette francesi ko:분류:프랑스 요리 nl:Categorie:Franse keuken

title: Category:French recipes


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Category:German recipes

Recipes from Germany.

ko:분류:독일 요리 nl:Categorie:Duitse keuken

title: Category:German recipes


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Category:Greek recipes

Recipes from Greece.

de:Kategorie:Kochbuch/ Griechische Küche fr:Catégorie:Cuisine grecque it:Categoria:Ricette greche nl:Categorie:Griekse keuken pl:Kategoria:Kuchnia grecka

title: Category:Greek recipes


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Category:Hungarian recipes

Recipes from Hungary.

title: Category:Hungarian recipes


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Category:Irish recipes

Recipes from Ireland.

title: Category:Irish recipes


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Category:Italian recipes

Recipes from Italy.

de:Kategorie:Kochbuch/ Italienische Küche es:Categoría:Gastronomía de Italia it:Categoria:Ricette regionali ko:분류:이탈리아 요리 nl:Categorie:Italiaanse keuken

title: Category:Italian recipes


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Category:Dutch recipes

Recipes from the Netherlands.

nl:Categorie:Nederlandse keuken

title: Category:Dutch recipes


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Category:Polish recipes

Recipes from Poland.

de:Kategorie:Kochbuch/ Polnische Küche fr:Catégorie:Cuisine polonaise pl:Kategoria:Kuchnia polska

title: Category:Polish recipes


text:
Category:Romanian recipes

Recipes from Romania.

title: Category:Romanian recipes


text:
Category:Russian recipes

Recipes from Russia.

title: Category:Russian recipes


text:
Category:Spanish recipes

Recipes from Spain.

es:Categoría:Cocina española fr:Catégorie:Cuisine espagnole it:Categoria:Ricette spagnole nl:Categorie:Spaanse keuken

title: Category:Spanish recipes


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Category:Turkish recipes

Recipes from Turkey.

nl:Categorie:Turkse keuken

title: Category:Turkish recipes


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Category:English recipes

Recipes from England.

title: Category:English recipes


text:
Category:Scottish recipes

Recipes from Scotland.

de:Kategorie:Kochbuch/ Schottische Küche

title: Category:Scottish recipes


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Category:Welsh recipes

Recipes from Wales.

title: Category:Welsh recipes


text:
Category:Middle Eastern recipes

Recipes from the Middle East.

title: Category:Middle Eastern recipes


text:
Category:Pacific recipes

Recipes from the Pacific region.

title: Category:Pacific recipes


text:
Category:South American recipes

Recipes from South America.

title: Category:South American recipes


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Category:North American recipes

Recipes from North America.

title: Category:North American recipes


text:
Category:South Asian recipes

Recipes from South Asia.

title: Category:South Asian recipes


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Perl Programming/CGI

Assuming you already have an Apache server (or compatible server that reads a shebang! line - more on this in a moment) and a Perl installation running, it is fairly simple to start running a Perl program on the Internet.

First, you must have some way to access the program. Here we will deal with form data and submission, so we will assume that your form code in HTML has a property saying ACTION="programname.cgi".

The initial setup
CGI scripts begin like any other Perl program, with a "shebang", something like:

(see Perl Programming/First Programs for details)

Next load the CGI module:

The CGI module makes our work easy because it has pre-programmed functions in it for Internet use. Then we must create a handle to CGI - something that allows us to access the functions. We do this with:

This means that the variable $query is loading the CGI standard functions.

Now that our program is setup using the CGI module, it should look something like this:

So we have a program, it just doesn't do anything yet, and will actually cause a server error because the server has no output or any idea of what kind of output to display even if it had some.

Retrieving Information
Before we tell the server what to do with our output, we need to retrieve our input. To do this, we use the $query variable we declared earlier. Say we have a text box in the form that is named "Name" and we want to find out what was typed there. To do this, we put the following line of code in our program:

Now, this line of code introduces us to the param function (for "parameter"). The param function can do quite a few handy tricks for us, all of them nice ways to retrieve our variables. It processes all of the HTTP coding so all we get is a nice clean variable. Another note, you aren't required to use $Name as your variable. It's simply more convenient to only remember one name for the same variable. Still, use what's best for you.

Output
Now we must create our header information. CGI even makes THIS easy for us. Instead of memorizing a bunch of mime-type declarations (that you may do as well), all we must do is type:

and it prints out our header information. A note about headers. Inside the parenthesis, we may specify parameters like cookies to send to the user's browser. This becomes very useful later. For now we will just stick to the headers.

The last thing you need to put (though the program will run, displaying a blank page without it) is some output. Let's simply have it display the user's name back to them. This would look like.

The finished code
So we now have a complete program that processes a form, using only six lines of code. Isn't Perl great? The final code looks like this:

When put into perspective, we can see that the $query variable is a very important connection to the CGI module as it tells perl that the function you are referencing belongs to CGI; Again, you may declare any variable name in the place of $query so long as you are consistent, though you will find many developers use $query or <tt>$q</tt>. Also note the use of the <tt>escapeHTML</tt> method to avoid any HTML injection problems.

Final note: Make sure you change <tt>/usr/bin/perl</tt> to the path of your perl installation (assuming that is not it) so perl will execute properly.

Frameworks
There are a number of CGI frameworks to help with common CGI programming tasks:

 * CGI::Application
 * Catalyst

Perl/CGI

title: Perl Programming/CGI


text:
TeX/hbadness

Synopsis
\hbadness=[number]

Description
A parameter that tells TeX at what point to report badness errors (i.e. underfull and overfull error). [number] ranges from 0 to 10000.

title: TeX/hbadness


text:
TeX/tolerance

TeX

Synopsis
\tolerance=[number]

Description
A parameter that tells TeX's line-breaking algorithm how much badness is allowable in a paragraph. [number] can range from 0 to 10000, and there are no units.

As TeX breaks paragraphs into lines, the first attempt that produces acceptable results according to \tolerance are used ; therefore, increasing this value will produce faster results, while allowing additional whitespace on each line.

Decreasing this value will improve the results of typesetting where better results are possible, but may also produce poor results with overfull boxes where no line-breaking combination can be found to meet this tolerance.

\tolerance should generally be set above \pretolerance, which attempts to set the paragraph without hyphenation if the results are good enough; setting without hyphenation is faster as fewer breakpoints must be considered.

title: TeX/tolerance


text:
TeX/input

< TeX

Synopsis
\input [file]

Description
TeX will process the file [file]. If [file] is of the form foo.tex, then \input foo.tex is the same as \input foo

title: TeX/input


text:
TeX/hfuzz

Synopsis
\hfuzz=[length]

Description
A parameter that allows hbox's to be overfull by [length] before an overfull error occurs.

Examples
\hfuzz=1pt allows hboxes to be up to 1pt overfull before an error occurs.

title: TeX/hfuzz