text:
Talk:Adobe

Wiki Education Foundation-supported course assignment
This article was the subject of a Wiki Education Foundation-supported course assignment, between 25 October 2020 and 12 December 2020. Further details are available on the course page. Student editor(s): Cube Wang. Peer reviewers: Dandan619, Mengyurui.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 13:26, 16 January 2022 (UTC)

Etymology
I couldn't find a reference for " The word adobe /əˈdoʊbiː/ has existed for around 4,000 years, with relatively little change in either pronunciation or meaning. The word can be traced from the Middle Egyptian (c. 2000 BC) word dbt "mud brick." As Middle Egyptian evolved into Late Egyptian, Demotic, and finally Coptic (c. 600 BC), τωωβε dj-b-t became tobe "[mud] brick." " Please provide references or remove text.

As referenced in the article (Oxford Dictionary). It states that the word is originally Arabic. — Preceding unsigned comment added by 2601:4:80:289:6A17:29FF:FE85:4927 (talk) 05:13, 30 June 2014 (UTC)

Pronunciation
Q Is this the author's own pronunciaton symbol scheme or one borrowed from the source encylopedia. In any case, I think if you use a pronunciation guide you should reference it. As it is, this pronunciation could be construed as a number of things, and therefore, close to useless...:-).. Our usual would be /a-doh'-bee/ I believe. Your worst nightmare

Origin of adobe techniques
Does the article claim that the adobe technique used in Spain came from the Americas insted of the Moors? I don't quite understand. -- Davidme —Preceding undated comment added 03:06, 2 March 2003.

Unit error
"16 mm (1/16th of an inch)". 256mm. That's a bloody big inch :) (One of those is probably a typo). --blades 17:26, May 8, 2004 (UTC)
 * Seems to be fixed now (can't find the text that you quote). --Singkong2005 00:40, 21 February 2006 (UTC)

Suggest 4 possible wiki links and 1 possible backlink for Adobe.
An automated Wikipedia link suggester has some possible wiki link suggestions for the Adobe article:

Additionally, there are some other articles which may be able to linked to this one (also known as "backlinks"): Notes: The article text has not been changed in any way; Some of these suggestions may be wrong, some may be right. Feedback: I like it, I hate it, Please don't link to — LinkBot 11:32, 1 Dec 2004 (UTC)
 * Can link the Middle East: ...e of adobe. Buildings made of sun-dried earth are common in the Middle East, North Africa, and in Spain (usually in the Mudejar sty...
 * Can link North Africa: ...ings made of sun-dried earth are common in the Middle East, North Africa, and in Spain (usually in the Mudejar style), but adobe...
 * Can link raw material: ...lay is used by Pueblo Indians to make the raw material for production of pottery or even to make molds for the... (link to section)
 * Can link rammed earth: ...n== Because an adobe wall, either made of bricks or using a rammed earth technique, is quite massive it will hold heat or cold. That... (link to section)
 * In Example Scrabble tournament game, can backlink ADOBE: ...ediately after the game, he regretted not having played 15f ADOBE for 29 points. He feared that it might set up a big play i...
 * Done. Added all the links except raw material; didn't link the backlink. JesseW 02:32, 2 Dec 2004 (UTC)

Mudbrick
Is there any need for the mudbrick article? I suppose it can just redirect to this article. China Crisis 20:52, 3 January 2006 (UTC)

Mudbrick is described as having a very short lifespan, 30 years and generally is poor. Adobe is described as being much more effective. I think it must be the formula that makes the difference. Lotusduck 01:42, 12 January 2006 (UTC)

The "formula" does indeed make a big difference. Adobe varies so widely that no  estimate of lifespan is useful without qualification. A useful estimate would have to include climate in which it is found, whether it has been maintained, it's ingredients, and type of construction.

Thus an adobe house built on concrete footings protects the bricks from spashes of rainfall and erosion of the bottom of a wall - a constant problem. Annual re-plastering is common in some parts of the world. I have read reports of an adobe house built and lived in for decades in a rain forest ! Some near-eastern locations have adobe structures older than two millenia. Mixing either cement or bitumen with natural adobe creates a brick which competes with fired clay in longevity ands water resistence.Stasi2 15:37, 5 September 2006 (UTC)

This and the mudbrick article should IMHO be combined or at least thought through more systematically. As presently presented (and linked to other articles) there is a lot of overlap but some questionable patterns. Some questions:
 * Is there a clear typology for earthen materials in terms of composition - either human engineered or natural (i.e., the clay, lime, sand, & OM naturally occuring)? If so, could it be the basis for a more logically organized set of articles?
 * Or is it related to climate (adobe where it's arid and earthen structures can be maintained for centuries, and mudbrick in more humid climates)? In which case maybe the pages should be merged.
 * Or is it more cultural - we use adobe, they (poor folks that they be) use mud bricks? On this one I'm not trying to score PC points - note that the mudbrick article is linked to the WikiProject International development project, but this adobe article is not...--A12n 19:13, 5 November 2006 (UTC)
 * NB- I was the one who added references to the Sahel and to the Great Mosque of Djenné to this article on adobe.--A12n 19:23, 5 November 2006 (UTC)
 * Now I see someone took out the reference to the Sahel which make no sense to me at all. Consider the multiple cultural, historic, etc. ties between North Africa which is retained in the article and the Sahel which is deleted. What makes it "adobe" on one side of the Sahara and not on the other? --A12n 00:21, 9 December 2006 (UTC)

error in text
The text says that Adobe brickmaking was brought to the Americas in the 16th century, but I just linked to this atricle from the Mayan civilization article, in the Building materials sections...seems like a simple overlook, but could use some checking into...

Another possible error is in the Adobe bricks sections: "If the sediment collects on the bottom, that indicates there is a high clay content and is good for adobe. If the mixture remains a liquid, then there is little clay in the soil and using it would yield weak bricks." That's the opposite to what I think it should be but 'm no expert on this. Anyone else? —Preceding unsigned comment added by 203.201.132.13 (talk) 23:44, 27 August 2008 (UTC)

wikibook
a part of this is written like a very incomplete how-to. Lets do some research and make a wikibook that tells the average person how to make their own adobe bricks, after all, it should mostly be a matter of the right proportion of both materials. People could learn and maybe help themselves landscape their yard. Who is with me? Lotusduck 01:52, 12 January 2006 (UTC)

Not quite that easy as soil/dirt varies in its suitability for adobe bricks. Must have the right clay/sand content.

Categories?
I'm wondering whether there should be a category called "sustainable technology" - but perhaps it would overlap too much with categories like Category:Appropriate technology & Category:Renewable energy. For the moment, I'll just use Category:Appropriate technology (which is a subcategory of Category:Development and Category:Sustainability).

In the cases of Rammed earth, Adobe & Dutch brick, I think they reasonably belong in Category:Appropriate technology. At the moment, though, the Appropriate technology aspect of these technologies is not developed in the articles. Anyway, feel free to make a different edit or suggestion.

btw, Mudbrick needs either a lot of work, or to be merged with the Adobe article. --Singkong2005 02:58, 17 February 2006 (UTC)

Suggested merge
This article and the mudbrick article imply that they are the same thing. I'm not sure that this is true - someone from a permaculture garden told me that adobe is built up from mud and then allowed to dry, whereas mudbricks are made into bricks and then dried. However, the articles seem to suggest otherwise, and so I've put the merge tags up so that we can discuss and resolve the issue. --Singkong2005 05:19, 11 May 2006 (UTC)

VOTE FOR MERGE; They are closely related enough to describe in a single article. Mudbrick could have a section in the Adobe article if needed. --Kaleb.G 23:59, 17 May 2006 (UTC)

I think that merging the two is more reasonable. I believe that mudbrick is a forerunner to adobe but still not monumental enough to have it's own article. I have also heard that the only difference between the two is materials used, not methods used to produce (though these methods may change slightly from region to region). Look at other articles in this subject, such as concrete. The Concrete article has the different types of materials and processes used throughout history. I think that mentioning mudbrick in this same context within the Adobe article would be totally sufficient.

I dissagree... In parts of Africa, mud brick can also describe a method of construction where bricks are actually cut out of the hard earth under dry lakebeds (and often simply out of quarries that are not near a water source) and then stacked and coated with plaster.
 * Where exactly? This sounds interesting enough to merit an article. Re the topic of merging the articles, maybe what we are talking about is 2 kinds of "mud bricks" - one molded (merge that and adobe) and the other cut, per what you describe. The main problem here seems to be names (see also my remarks above); on another level there might be a kind of strategy for the articles on building with earth that would have a summary page (with definitions of categories and links to the main articles). --A12n 00:06, 9 December 2006 (UTC)

Possible Vandalism
Some joker seems to have added "Drek pek sex" to the article section about the composition of adobe. What Italic textisItalic text that?

Category
This article us coming up under a Chemistry Link. Don't think this has much to do with chemistry in the classic sense.
 * Closest I could see would be soil composition, but you are right that a link to chemistry seems a little removed (though I wonder if anyone has looked at soil pH and adobe/mudbrick quality; most soils in arid/semi-arid areas tend to be alkaline I believe). I still need to find time to deal with this article and mudbrick and in that context would discuss soils as the material but not chemistry per se. --A12n 18:26, 7 March 2007 (UTC)

Question
I'm reading a book entitled Native North American Art by Berlo and Philips, where it is written, "Anasazi construction techniques at Chaco Canyon and Mesa Verde favoured the use of stone blocks. In the last few centuries, however, most Pueblo architecture has used adobe bricks as building blocks. Made in wooden moulds, by hand, by many members of the community, adobe block construction was an innovation introduced by the Spanish" (p. 49).

If Anasazi culture had extensive trade and cultural exchange with the Mimbres Mogollon culture, which extended into southern Mexico, then how is the following statement from the Wiki article true? "[A]dobe had been in use by indigenous peoples of the Americas in the Southwestern United States, Mesoamerica, and the Andean region of South America for several thousand years, although often substantial amounts of stone are used in the walls of Pueblo buildings." Voxmea 00:28, 28 February 2007 (UTC)

For a 6th grade class project in social studies, my daughter was tasked with making a mud brick. No specific formula was given, and mud bricks were tested and compared in a sort of competition with three trials. 1. bricks were "rolled" across a hard surface (wear-test). 2. bricks were soaked under water for 30 seconds. 3. bricks were load-tested with 50 pounds (US) weight. We used the formula supplied with this wikipedia article; ROUGHLY 50% sand (from Pismo Beach, CA, a fine, high-quality sand), 35% clay (local - very chalky yellowish-white stuff, pounded to a fine powder - this clay DID pass the sediment-test, very well!), and 15% hay. Resulting liquid mixture behaved like a non-Newtonian fluid. Brick was dried in an oven approx 17 hrs at 190 degrees F. Resulting brick was very crumbly. Failed the first test. Next time; I would try MUCH less sand; and probably try to do something to compress the clay mixture. —Preceding unsigned comment added by 64.166.166.204 (talk) 05:42, 11 December 2007 (UTC)

Think of the sediment test sort of like a centrifuge. The sand should fall out of solution first, then lighter silt, then clay. It's the relative thickness of these layers that tells you how good the soil will be for adobe. There IS sand in clay, so if you added more, chances are you had too much. Also, try lowering the drying temperature or even misting the bricks down as they're drying. The longer they cure, the stronger they'll be. ◗●◖ falkreon (talk) 19:33, 19 May 2009 (UTC)

Adobe in Spain and New Spain
The Moors introduced adobe construction to Spain and then the Spaniards brought it to their New World colonies. Prior to Spanish settlement of current New Mexico the indigenous people used puddled mud construction by stacking damp earth to form walls without making bricks first. —Preceding unsigned comment added by 68.35.150.103 (talk) 00:54, 22 September 2008 (UTC)

Banco as type of adobe ?
I added the Great Mosque of Djenné as an example building, thinking that banco is a type of adobe. Since it is made by fermenting rice husks with mud, I believe it to be adobe. KVDP (talk) 12:13, 18 June 2011 (UTC)

Suggested merge II
Noting User:Der Golem's suggestion to merge Mudbrick and Earth block into this article, which points to this page, I'm taking the opportunity to start the discussion. Note discussion above on the previous suggested merge with Mudbrick (2006), which ended inconclusively, and related discussion on Talk:Mudbrick. Note also that the Earth block article was created after this discussion, later in 2006, evidently as Compressed earth block.--A12n (talk) 03:03, 1 February 2015 (UTC)

Adding in merge from Chirpici.--A12n (talk) 04:41, 1 February 2015 (UTC)

 * Support merge of Mudbrick into Adobe. Don't think there was ever a clear set of criteria for distinguishing Adobe and Mudbrick, and a single article could treat the range of techniques and composition, as well as climatic and soil factors etc. that are encountered by this type of building material. (See also previous comments in Talk:Adobe and Talk:Mudbrick.)--A12n (talk) 03:03, 1 February 2015 (UTC)

 * Neutral on merge of Earthen block into Adobe. This article describes the product of a technique that is arguably distinguishable from Adobe/Mudbrick.--A12n (talk) 03:03, 1 February 2015 (UTC)
 * Oppose merging Earth block Compressed earth presses are new devices that are powered with gasoline engines or hydraulic presses - coming into being in the 1980's and use are distinguishable from older types. -- Aronzak (talk) 18:01, 5 June 2015 (UTC)

 * Support merge of Chirpici into Adobe. The local term for and use of adobe/mudbrick in Romania - does it need a separate article or a section in this one?--A12n (talk) 04:41, 1 February 2015 (UTC)

 * I have noted this topic myself in the past and contemplated suggesting a merge. However, I think mudbrick is a more international term so adobe should be merged into mudbrick instead of the suggested merge of mudbrick into adobe. The Online Etymology Dictionary states that adobe is American English. On the other hand adobe gets a lot more hits on Google search and has a lot more interlanguage links on Wikipedia. I agree earthen block may be different than adobe because they may also contain cement as a stabilizer and use more technology, a press, than hand filled and compacted molds for adobe bricks, but I think earthen block could be merged into mudbrick in a section which covers bricks with added chemical binders like cement and bitumen. I agree chirpici should merge into mudbrick just like banco has it's own section in mudbrick. Jim Derby (talk) 03:10, 15 March 2015 (UTC)
 * In researching adobe I have come to learn that adobe means three things: 1. a material derived from "adobe soil", 2. a sun dried brick, and 3. a house type. Adobe material has been used not just in bricks but like cob (puddled adobe) and for "poured adobe" (which I have not been able to find good information on yet), adobe plaster, poured adobe floors and I saw mention of poured adobe walls in formwork. With the additional meaning of adobe as a material and the different building methods I do not think adobe would merge well into mudbrick. I have also seen reference to compressed adobe and rammed adobe so the earth building terms are all loosely used and there are lots of regional synonyms. Jim Derby (talk) 03:07, 20 March 2015 (UTC)
 * So, after doing my homework I oppose merging adobe and mudbrick. The adobe article can be clarified and greatly expanded to cover the other methods of using the material and the ratio of ingredients. The mud brick aspects of adobe can be mostly covered in mudbrick as the "main article". Mudbrick can be greatly expanded including the history, materials, repair and maintenance and comparisons with rammed earth, compressed earth blocks, cob, fired brick, sandcrete, etc.
 * Oppose merging earthen block into adobe. Earthen block should be renamed compressed earth block and discuss that subject. The technology used to make compressed earth blocks is substantially different than to make mud bricks.
 * Support merge of Chirpici into mud-brick (not adobe). Jim Derby (talk) 12:36, 23 March 2015 (UTC)

 * Agree with Jim. Not all adobe is made into mudbricks before use, nor are all mudbricks made from adobe, so the two terms are not synonymous and the articles should not be merged. The articles can use some editing to make this clearer. "Chirpici" is just a foreign language term for mudbricks and should not have an article in the English Wikipedia. And compressed earth blocks are a different, modern technology. I have already reverted the factually incorrect move there, and am adding a sentence clarifying and distinguishing them from mudbricks. oknazevad (talk) 15:15, 12 June 2015 (UTC)

"Middle America" photo
I removed this GF addition because - to my eye - it did not look like an example of adobe so much as stucco over brick and wood, which were both visible in the photograph. But I was mistaken, as confirmed by the photo's creator. I do however think that the photo is better as an example of the style rather than as an exemplar, and have therefore moved it to the gallery, down from the prior position at the top. Comments welcome. Thanks. JohnInDC (talk) 13:58, 8 July 2015 (UTC)
 * The home, that you can see was built of Adobe to the right, was later added on to with a wood structure. The Adobe bricks are seen clearly, on the right while the regular bricks were used to create a fireplace. You do see what looks to be stucco over brick, but Adobe is weathering and eroding away. It looks fine where it is. Cheers! talk→   WPPilot   20:08, 9 July 2015 (UTC)

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Great Article! Perhaps a mention that ADOBE can be used as a ART medium too?
Great article on the Adobe being used as a construction medium.But it can also be used as a ARTISTIC modeling scullpture medium too! Thanks!Eddson storms (talk) 00:36, 25 December 2016 (UTC)

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

title: Talk:Adobe


text:
Adobe Inc.

Adobe Inc., formerly Adobe Systems Incorporated, is an American computer software company based in San Jose, California. It offers a wide range of programs from web design tools, photo manipulation and vector creation, through to video/audio editing, mobile app development, print layout and animation software. It has historically specialized in software for the creation and publication of a wide range of content, including graphics, photography, illustration, animation, multimedia/video, motion pictures, and print. Its flagship products include Adobe Photoshop image editing software; Adobe Illustrator vector-based illustration software; Adobe Acrobat Reader and the Portable Document Format (PDF); and a host of tools primarily for audio-visual content creation, editing and publishing. Adobe offered a bundled solution of its products named Adobe Creative Suite, which evolved into a subscription software as a service (SaaS) offering named Adobe Creative Cloud. The company also expanded into digital marketing software and in 2021 was considered one of the top global leaders in Customer Experience Management (CXM).

Adobe was founded in December 1982 by John Warnock and Charles Geschke, who established the company after leaving Xerox PARC to develop and sell the PostScript page description language. In 1985, Apple Computer licensed PostScript for use in its LaserWriter printers, which helped spark the desktop publishing revolution. Adobe later developed animation and multimedia through its acquisition of Macromedia, from which it acquired Macromedia Flash; video editing and compositing software with Adobe Premiere, later known as Adobe Premiere Pro; low-code web development with Adobe Muse; and a suite of software for digital marketing management.

Adobe has more than 26,000 employees worldwide. Adobe also has major development operations in the United States in Newton, New York City, Arden Hills, Lehi, Seattle, Austin and San Francisco. It also has major development operations in Noida and Bangalore in India. The company has long been the dominant tech firm in design and creative software, despite attracting criticism for its policies and practices particularly around Adobe Creative Cloud's switch to subscription only pricing and its early termination fees for its most promoted Creative Cloud plan, the latter of which attracted a joint civil lawsuit from the US Federal Trade Commission and the US Department of Justice in 2024.

PostScript (1982–1986)
The company was started in John Warnock's garage. The name of the company, Adobe, comes from Adobe Creek in Los Altos, California, a stream which ran behind Warnock's house. That creek is named because of the type of clay found there (Adobe being a Spanish word for Mudbrick). Adobe's corporate logo features a stylized "A" and was designed by graphic designer Marva Warnock, John Warnock's wife. Steve Jobs attempted to buy the company for $5 million in 1982, but Warnock and Geschke refused. Their investors urged them to work something out with Jobs, so they agreed to sell him shares worth 19 percent of the company. Jobs paid a five-times multiple of their company's valuation at the time, plus a five-year license fee for PostScript, in advance. The purchase and advance made Adobe the first company in the history of Silicon Valley to become profitable in its first year.

Warnock and Geschke considered various business options including a copy-service business and a turnkey system for office printing. Then they chose to focus on developing specialized printing software and created the Adobe PostScript page description language.

PostScript was the first international standard for computer printing as it included algorithms describing the letter-forms of many languages. Adobe added kanji printer products in 1988. Warnock and Geschke were also able to bolster the credibility of PostScript by connecting with a typesetting manufacturer. They weren't able to work with Compugraphic, but then worked with Linotype to license the Helvetica and Times Roman fonts (through the Linotron 100). By 1987, PostScript had become the industry-standard printer language with more than 400 third-party software programs and licensing agreements with 19 printer companies.

Adobe's first products after PostScript were digital fonts which they released in a proprietary format called Type 1, worked on by Bill Paxton after he left Stanford. Apple subsequently developed a competing standard, TrueType, which provided full scalability and precise control of the pixel pattern created by the font's outlines, and licensed it to Microsoft.

Introduction of creative software (1986–1996)
Starting in the mid-1980s, Adobe entered the consumer software market, starting with Adobe Illustrator, a vector-based drawing program for the Apple Macintosh. Illustrator, which grew out of the firm's in-house font-development software, helped popularize PostScript-enabled laser printers. By the mid 1990s, Adobe would either develop or acquire Photoshop from John and Thomas Knoll, FrameMaker from Frame Technology Corporation, and After Effects and PageMaker from Aldus, as well as develop Adobe Premiere, later known as Premiere Pro, in-house, initially releasing it in 1991. Around the same time as the development of Illustrator, Adobe entered the NASDAQ Composite index in August 1986.

PDFs and file formats (1993–1999)
In 1993, Adobe introduced the Portable Document Format, commonly shortened to the initialism PDF, and its Adobe Acrobat and Reader software. Warnock originally developed the PDF under a code name, "The Camelot Project", using PostScript technology to create a widely available digital document format, able to display text, raster graphics, vector graphics, and fonts. Adobe kept the PDF as a proprietary file format from its introduction until 2008, when the PDF became an ISO international standard under ISO number ISO 32000-1:2008, though the PDF file format was free for viewers since its introduction.

With its acquisition of Aldus, in addition to gaining PageMaker and After Effects, Adobe gained control over the TIFF file format for images.

Creative Suite and the Macromedia acquisition (2000–2009)
The 2000s saw various developments for the company. Its first notable acquisition in the decade was in 2002, when Adobe acquired Canadian company Accelio, also known as JetForm. In May 2003, Adobe purchased audio editing and multitrack recording software Cool Edit Pro from Syntrillium Software for $16.5 million, as well as a large loop library called "Loopology". Adobe then renamed Cool Edit Pro to Adobe Audition.

It was in 2003 that the company introduced the first version of Adobe Creative Suite, bundling its creative software into a single package. The first version of Creative Suite introduced InDesign (the successor to PageMaker), Illustrator, Photoshop, ImageReady and InCopy, with the 2005 second edition of Creative Suite including an updated version of Adobe Acrobat, Premiere Pro, GoLive, the file manager Adobe Bridge, and Adobe Dreamweaver, the latter of which was acquired from a $3.4 billion acquisition of Macromedia, most notably.

In addition to bringing in Dreamweaver, the $3.4 billion Macromedia acquisition, completed as a stock swap, added ColdFusion, Contribute, Captivate, Breeze (rebranded as Adobe Connect), Director, Fireworks, Flash, FlashPaper, Flex, FreeHand, HomeSite, JRun, Presenter, and Authorware to Adobe's product line.

By April 2008, Adobe released Adobe Media Player. On April 27, Adobe discontinued the development and sales of its older HTML/web development software, GoLive, in favor of Dreamweaver. Adobe offered a discount on Dreamweaver for GoLive users and supports those who still use GoLive with online tutorials and migration assistance. On June 1, Adobe launched Acrobat.com, a series of web applications geared for collaborative work. Creative Suite 4, which includes Design, Web, Production Premium, and Master Collection came out in October 2008 in six configurations at prices from about US$1,700 to $2,500 or by individual application. The Windows version of Photoshop includes 64-bit processing. On December 3, 2008, Adobe laid off 600 of its employees (8% of the worldwide staff) citing the weak economic environment.

On September 15, 2009, Adobe Systems announced that it would acquire online marketing and web analytics company Omniture for $1.8 billion. The deal was completed on October 23, 2009. Former Omniture products were integrated into the Adobe Marketing Cloud.

On November 10, 2009, the company laid off a further 680 employees.

End of Flash, security breach, and employee compensation class action (2010–2014)
Adobe's 2010 was marked by continuing arguments with Apple over the latter's non-support for Adobe Flash on its iPhone, iPad and other products. Former Apple CEO Steve Jobs claimed that Flash was not reliable or secure enough, while Adobe executives have argued that Apple wishes to maintain control over the iOS platform. In April 2010, Steve Jobs published a post titled Thoughts on Flash where he outlined his thoughts on Flash and the rise of HTML5. In July 2010, Adobe bought Day Software integrating their line of CQ Products: WCM, DAM, SOCO, and Mobile

In January 2011, Adobe acquired DemDex, Inc. with the intent of adding DemDex's audience-optimization software to its online marketing suite. At Photoshop World 2011, Adobe unveiled a new mobile photo service. Carousel was a new application for iPhone, iPad, and Mac that used Photoshop Lightroom technology to allow users to adjust and fine-tune images on all platforms. Carousel also allowed users to automatically sync, share and browse photos. The service was later renamed "Adobe Revel". Later that same year in October, Adobe acquired Nitobi Software, the maker of the mobile application development framework PhoneGap. As part of the acquisition, the source code of PhoneGap was submitted to the Apache Foundation, where it became Apache Cordova.

In November 2011, Adobe announced that they would cease development of Flash for mobile devices following version 11.1. Instead, it would focus on HTML5 for mobile devices. In December 2011, Adobe announced that it had entered into a definitive agreement to acquire privately held Efficient Frontier.

In December 2012, Adobe opened a new 280000 sqft corporate campus in Lehi, Utah.

In 2013, Adobe endured a major security breach. Vast portions of the source code for the company's software were stolen and posted online and over 150 million records of Adobe's customers were made readily available for download. In 2012, about 40 million sets of payment card information were compromised by a hack at Adobe.

A class-action lawsuit alleging that the company suppressed employee compensation was filed against Adobe, and three other Silicon Valley-based companies in a California federal district court in 2013. In May 2014, it was revealed the four companies, Adobe, Apple, Google, and Intel had reached an agreement with the plaintiffs, 64,000 employees of the four companies, to pay a sum of $324.5 million to settle the suit.

Adobe Creative Cloud (2011–present)
2011 saw the company first introduce Adobe Creative Cloud, a $600/year subscription plan to its creative software as opposed to a one-time perpetual license payment which could often top $2000 for creative professionals. The initial launch of Creative Cloud alongside Creative Suite 5 users came at the same time that Adobe ran into controversy from users of Adobe's creative software, with users of Adobe software stating that the original perpetual and subscription pricing plans for CS5 would be unaffordable for not only individuals but also businesses, as well as refusing to extend a Creative Suite 6 discount to non-CS5 users. The original announcement of Adobe Creative Cloud was met with a positive reception from CNET journalists as a much more enticing plan, and Creative Cloud was first released in 2012, though a later CNET survey evidenced that more users had a negative perception about subscription creative software than a positive view. The original pricing plan for Creative Cloud was $75 per month for the entire suite of software, though Adobe discounted the monthly cost to $50 for users willing to commit to at least one year of continuous subscription for Creative Cloud, and down to $30 per month for former CS users with the one year commitment.

By 2013, Adobe decided that CS6 would be the last version of Creative Suite software that would be sold through perpetual licensing option, and in May announced that a Creative Cloud subscription would be the only way to get the newest versions of Photoshop, Illustrator, and other Adobe creative software. Reception to the mandatory subscriptions for future Adobe software was mostly negative, despite some positive testimonies on the move from customers and Adobe's attraction of 500,000 Creative Cloud subscribers by the service's first year. The switch to subscription only also did not deter software piracy of Creative Cloud services; within the first day of the first version of Photoshop exclusively made for Creative Cloud being released, cracked versions of Adobe Photoshop CC 2013 were found on The Pirate Bay, an online website used for distributing pirated software.

Further acquisitions and failed buyout of Figma (2018–2023)
In March 2018, at Adobe Summit, the company and Nvidia announced their association to upgrade their AI and profound learning innovations. They planned to streamline Adobe Sensei AI and machine learning structure for Nvidia GPUs. Adobe and Nvidia had cooperated for 10 years on GPU quickening. This incorporates Sensei-powered features, e.g. auto lip-sync in Adobe Character Animator CC and face-aware editing in Photoshop CC, and also cloud-based AI/ML items and features, for example, picture investigation for Adobe Stock and Lightroom CC and auto-labeling in Adobe Experience Supervisor.

Adobe further spent its time from 2018 to 2023 acquiring more companies to boost both Creative Cloud and the Adobe Experience Cloud, a software suite which increased business. These included e-commerce services provider Magento Commerce from private equity firm Permira for $1.68 billion in June 2018, Marketo for $4.75 billion in 2018, Allegorithmic in 2019 for just under $160 million,  and Workfront in December 2020 for $1.5 billion. 2021 additionally saw Adobe add payment services to its e-commerce platforms in an attempt to compete with Shopify, accepting both credit cards and PayPal.

In July 2020, as the United States presidential elections approached, the software giant imposed a ban on the political ads features on its digital advertising sales platform.

On November 9, 2020, Adobe announced it would spend US$1.5 billion to acquire Workfront, a provider of marketing collaboration software. The acquisition was completed in early December 2020.

On August 19, 2021, Adobe announced it had entered into a definitive agreement to acquire Frame.io, a leading cloud-based video collaboration platform. The transaction is valued at $1.275 billion and closed during the fourth quarter of Adobe's 2021 fiscal year.

Adobe's biggest acquisition was announced in 2022, where it announced that it had agreed to buy Figma, an Adobe XD competitor, for $20 billion, along with 15 months of regulatory scrutiny from the US and European Union. This was due to concerns that Adobe, already a major player in the design software market with XD, would have too much control if it also owned Figma; at the time of the announcement to acquire Figma, Adobe's share over the creative software market and design-software market was almost a monopoly. In December 2023, the two companies called off their merger, citing the regulatory challenges as a sign to both that the deal was not likely to be approved. Adobe paid Figma a $1 billion termination fee per their merger agreement.

FTC lawsuit and terms of service update (2024–present)
On June 17, 2024, the US Federal Trade Commission together with the US Department of Justice filed a lawsuit against Adobe for its subscription business model practice, citing hidden termination fees and the company pushing customers towards more expensive plans.

In June 2024, after facing backlash for its changes to the terms of service, Adobe updated them to explicitly pledge it will not use customer data to train its AI models.

Products
Adobe's currently supported roster of software, online services and file formats comprises the following :

 * Digital Marketing Management Software
 * Adobe Experience Cloud, Adobe Experience Manager (AEM 6.2), XML Documentation add-on (for AEM), Mixamo

 * Formats
 * Portable Document Format (PDF), PDF's predecessor PostScript, ActionScript, Shockwave Flash (SWF), Flash Video (FLV), and Filmstrip (.flm)

 * Web-hosted services
 * Adobe Color, Photoshop Express, Acrobat.com, Behance and Adobe Express.

 * Adobe Renderer
 * Adobe Media Encoder

 * Adobe Stock
 * A microstock agency that presently provides over 57 million high-resolution, royalty-free images and videos available to license (via subscription or credit purchase methods). In 2015, Adobe acquired Fotolia, a stock content marketplace founded in 2005 by Thibaud Elziere, Oleg Tscheltzoff, and Patrick Chassany which operated in 23 countries. It is run as a stand-alone website.

 * Adobe Experience Platform
 * A family of content, development, and customer relationship management products, with what Adobe calls the "next generation" of its Sensei artificial intelligence and machine learning framework, introduced in March 2019.

Reception
Since 2000, Fortune has recognized Adobe as one of the 100 Best Companies to Work For. In 2021, Adobe was ranked 16th. Glassdoor recognized Adobe as a Best Place to Work. In October 2021, Fast Company included Adobe on their Brands That Matter list. In October 2008, Adobe Systems Canada Inc. was named one of "Canada's Top 100 Employers" by Mediacorp Canada Inc. and was featured in Maclean's newsmagazine.

Adobe received a five-star rating from the Electronic Frontier Foundation with regard to its handling of government data requests in 2017.

In 2022, Adobe was listed as one of the Best Places to Work for Disability Inclusion by the Disability Equality Index (DEI).

Pricing
Adobe has been criticized for its pricing practices, with retail prices being up to twice as much in non-US countries.

After Adobe revealed the pricing for the Creative Suite 3 Master Collection, which was £1,000 higher for European customers, a petition to protest over "unfair pricing" was published and signed by 10,000 users. In June 2009, Adobe further increased its prices in the UK by 10% in spite of weakening of the pound against the dollar, and UK users were not allowed to buy from the US store.

Adobe's Reader and Flash programs were listed on "The 10 most hated programs of all time" article by TechRadar.

Security
Hackers have exploited vulnerabilities in Adobe programs, such as Adobe Reader, to gain unauthorized access to computers. Adobe's Flash Player has also been criticized for, among other things, suffering from performance, memory usage and security problems. A report by security researchers from Kaspersky Lab criticized Adobe for producing the products having top 10 security vulnerabilities.

Observers noted that Adobe was spying on its customers by including spyware in the Creative Suite 3 software and quietly sending user data to a firm named Omniture. When users became aware, Adobe explained what the suspicious software did and admitted that they: "could and should do a better job taking security concerns into account". When a security flaw was later discovered in Photoshop CS5, Adobe sparked outrage by saying it would leave the flaw unpatched, so anyone who wanted to use the software securely would have to pay for an upgrade. Following a fierce backlash Adobe decided to provide the software patch.

Adobe has been criticized for pushing unwanted software including third-party browser toolbars and free virus scanners, usually as part of the Flash update process, and for pushing a third-party scareware program designed to scare users into paying for unneeded system repairs.

Customer data breach
On October 3, 2013, the company initially revealed that 2.9 million customers' sensitive and personal data was stolen in a security breach which included encrypted credit card information. Adobe later admitted that 38 million active users have been affected and the attackers obtained access to their IDs and encrypted passwords, as well as to many inactive Adobe accounts. The company did not make it clear if all the personal information was encrypted, such as email addresses and physical addresses, though data privacy laws in 44 states require this information to be encrypted.

In late 2013 a 3.8 GB file stolen from Adobe and containing 152 million usernames, reversibly encrypted passwords and unencrypted password hints was posted on AnonNews.org. LastPass, a password security firm, said that Adobe failed to use best practices for securing the passwords and has not salted them. Another security firm, Sophos, showed that Adobe used a weak encryption method permitting the recovery of a lot of information with very little effort. According to IT expert Simon Bain, Adobe has failed its customers and 'should hang their heads in shame'.

Many of the credit cards were tied to the Creative Cloud software-by-subscription service. Adobe offered its affected US customers a free membership in a credit monitoring service, but no similar arrangements have been made for non-US customers. When a data breach occurs in the US, penalties depend on the state where the victim resides, not where the company is based.

After stealing the customers' data, cyber-thieves also accessed Adobe's source code repository, likely in mid-August 2013. Because hackers acquired copies of the source code of Adobe proprietary products, they could find and exploit any potential weaknesses in its security, computer experts warned. Security researcher Alex Holden, chief information security officer of Hold Security, characterized this Adobe breach, which affected Acrobat, ColdFusion and numerous other applications, as "one of the worst in US history". Adobe also announced that hackers stole parts of the source code of Photoshop, which according to commentators could allow programmers to copy its engineering techniques and would make it easier to pirate Adobe's expensive products.

Published on a server of a Russian-speaking hacker group, the "disclosure of encryption algorithms, other security schemes, and software vulnerabilities can be used to bypass protections for individual and corporate data" and may have opened the gateway to new generation zero-day attacks. Hackers already used ColdFusion exploits to make off with usernames and encrypted passwords of PR Newswire's customers, which has been tied to the Adobe security breach. They also used a ColdFusion exploit to breach Washington state court and expose up to 200,000 Social Security numbers.

Anti-competitive practices
In 1994, Adobe acquired Aldus Corp., a software vendor that sold FreeHand, a competing product. FreeHand was direct competition to Adobe Illustrator, Adobe's flagship vector-graphics editor. The Federal Trade Commission (FTC) intervened and forced Adobe to sell FreeHand back to Altsys, and also banned Adobe from buying back FreeHand or any similar program for the next 10 years (1994–2004). Altsys was then bought by Macromedia, which released versions 5 to 11. When Adobe acquired Macromedia in December 2005, it stalled development of FreeHand in 2007, effectively rendering it obsolete. With FreeHand and Illustrator, Adobe controlled the only two products that compete in the professional illustration program market for Macintosh operating systems.

In 2011, a group of 5,000 FreeHand graphic designers convened under the banner Free FreeHand, and filed a civil antitrust complaint in the US District Court for the Northern District of California against Adobe. The suit alleged that:

"Adobe has violated federal and state antitrust laws by abusing its dominant position in the professional vector graphic illustration software market [...] Adobe has engaged in a series of exclusionary and anti-competitive acts and strategies designed to kill FreeHand, the dominant competitor to Adobe's Illustrator software product, instead of competing on the basis of product merit according to the principals of free market capitalism."

Adobe had no response to the claims and the lawsuit was eventually settled. The FreeHand community believes Adobe should release the product to an open-source community if it cannot update it internally.

, on its FreeHand product page, Adobe stated, "While we recognize FreeHand has a loyal customer base, we encourage users to migrate to the new Adobe Illustrator CS4 software which supports both PowerPC and Intel-based Macs and Microsoft Windows XP and Windows Vista." , the FreeHand page no longer exists; instead, it simply redirects to the Illustrator page. Adobe's software FTP server still contains a directory for FreeHand, but it is empty.

Cancellation fees
In April 2021, Adobe received criticism from Twitter users for the company's cancellation fees after a customer shared a tweet showing they had been charged a $291.45 cancellation fee for their Adobe Creative Cloud subscription. Many also showed their cancellation fees for Adobe Creative Cloud, with this leading to many encouraging piracy of Adobe products and/or purchase of alternatives with lower prices or using free and open-source software instead. Furthermore, there have been reports that with changing subscriptions it is possible to avoid paying this fee.

The U.S. Department of Justice and the FTC filed a lawsuit against Adobe and two of its executives in June 2024, alleging that the company's deceptive subscription practices and cancellation policies violated the Restore Online Shoppers' Confidence Act. According to the lawsuit, the company purportedly used small text disclosures, optional input fields, and complex web of links to obscure a concealed early termination fee. This fee reportedly amounted to fifty percent of the remaining value of annual contracts for users who chose to cancel early in the first year, resulting in significant penalties. Customers who tried to cancel services by contacting customer service faced obstacles, including dropped calls and multiple transfers between representatives; others continued to be billed by Adobe, under the mistaken belief that they had successfully ended their subscriptions.

2024 terms of service update
On June 5, 2024, Adobe updated their terms of service (TOS) for Photoshop stating "we may access your content through both manual and automated methods, such as for content review." This sparked outrage with Adobe users, as the new terms implied that the users' work would be used to train Adobe's generative AI, even if the work was under a non-disclosure agreement (NDA).

Adobe responded the following day clarifying that they will not use user data to train generative AI or take users work as their own; however, they neglected to respond to the part in the TOS that gives Adobe the ability to view or use work that is contracted under an NDA.

Chief executive officers

 * John Warnock (1982–2000)
 * Bruce Chizen (2000–2007)
 * Shantanu Narayen (2007–present)

title: Adobe Inc.


text:
Alexander Technique

The Alexander Technique, named after its developer Frederick Matthias Alexander (1869–1955), is a type of alternative therapy based on the idea that poor posture gives rise to a range of health problems. The American National Center for Complementary and Integrative Health classifies it as a "psychological and physical" complementary approach to health when used "together with" mainstream methods. When used "in place of" conventional medicine, it is considered "alternative".

Alexander began developing his technique's principles in the 1890s in an attempt to address his own voice loss during public speaking. He credited his method with allowing him to pursue his passion for performing Shakespearean recitations.

Proponents and teachers of the Alexander Technique believe the technique can address a variety of health conditions, but there is a lack of research to support the claims. , the UK National Health Service and the National Institute for Health and Care Excellence (NICE) cite evidence which suggests that the Alexander Technique may be helpful for long-term back pain and for long-term neck pain, and that it could help people cope with Parkinson's disease. Both the American health-insurance company Aetna and the Australian Department of Health have conducted reviews and concluded that there is insufficient evidence for the technique's health claims to warrant insurance coverage.

Method
The Alexander Technique is most commonly taught in a series of private lessons which may last from 30 minutes to an hour. The number of lessons varies widely, depending on the student's needs and level of interest. Students are often performers, such as actors, dancers, musicians, athletes and public speakers, people who work on computers, or those who are in frequent pain for other reasons. Instructors observe their students, and provide both verbal and gentle manual guidance to help students learn how to move with better poise and less strain. Sessions include chair work – often in front of a mirror – during which the instructor will guide the student while the student stands, sits and walks, learning to move efficiently while maintaining a comfortable relationship between the head, neck, and spine, and table work or physical manipulation.

In the United Kingdom, there is no regulation for who can offer Alexander Technique services. Professional organisations do exist, however, typically offering three-year courses to people becoming instructors.

History
The Alexander Technique is based on the personal observations of Frederick Matthias Alexander (1869–1955). Alexander's career as an actor was hampered by recurrent bouts of laryngitis, but he found he could overcome it by focusing on his discomfort and tension, and relaxing. Alexander also thought posture could be improved if one became more conscious of one's own bodily movement.

While on a recital tour in New Zealand (1895), Alexander came to believe in the wider significance of improved carriage for overall physical functioning, although evidence from his own publications appears to indicate it happened less systematically and over a long period of time.

Alexander did not originally conceive of his technique as therapy, but it has become a form of alternative medicine.

When considering how to classify the Alexander Technique in relation to mainstream medicine, some sources describe it as alternative and/or complementary, depending on whether it is used alone or with mainstream methods. The American National Center for Complementary and Integrative Health classifies it as a "psychological and physical" complementary approach to health when used with mainstream methods. When used "in place of" conventional medicine, it is considered "alternative".

Influence
The American philosopher and educator John Dewey became impressed with the Alexander Technique after his headaches, neck pains, blurred vision, and stress symptoms largely improved during the time he used Alexander's advice to change his posture. In 1923, Dewey wrote the introduction to Alexander's Constructive Conscious Control of the Individual.

Fritz Perls, who originated Gestalt therapy, credited Alexander as an inspiration for his psychological work.

Uses
The Alexander Technique is used as a therapy for stress-related chronic conditions. It does not attempt to cure the underlying cause, but to teach people how to avoid bad habits which might exacerbate their condition.

The Technique is used as an alternative treatment to improve both voice and posture for people in the performing arts. it was on the curriculum of prominent Western performing arts institutions.

According to Alexander Technique instructor Michael J. Gelb, people tend to study the Alexander Technique for reasons of personal development.

Health effects
The UK National Health Service says that advocates of the Alexander Technique made claims for it that were not supported by evidence, but that there was evidence suggesting that it might help with chronic back or neck pain. According to the NHS, Alexander technique may be of benefit for people with Parkinson disease. The National Institute for Health and Care Excellence (NICE) guidelines state that people with Parkinson disease who are experiencing balance or motor function problems should consider the Alexander Technique along with disease-specific physiotherapy. There is limited evidence for chronic pain, stammering, and balance skills in older people. There was no good evidence of benefit for other conditions including asthma, headaches, osteoarthritis, difficulty sleeping, and stress.

A 2012 Cochrane systematic review found that there is no good evidence that the Alexander Technique is effective for treating asthma, and randomized clinical trials are needed in order to assess the effectiveness of this type of treatment approach.

A review published in BMC Complementary and Alternative Medicine in 2014 focused on "the evidence for the effectiveness of AT sessions on musicians' performance, anxiety, respiratory function and posture" concluded that "evidence from RCTs and CTs suggests that AT sessions may improve performance anxiety in musicians. Effects on music performance, respiratory function and posture yet remain inconclusive."

A 2015 review, conducted for the Australian Department of Health in order to determine what services the Australian government should pay for, examined clinical trials published to date and found that "overall, the evidence was limited by the small number of participants in the intervention arms, wide confidence intervals or a lack of replication of results." It concluded that "the Alexander Technique may improve short-term pain and disability in people with low back pain, but the longer-term effects remain uncertain. For all other clinical conditions, the effectiveness of the Alexander Technique was deemed to be uncertain, due to insufficient evidence." It also noted that "evidence for the safety of Alexander Technique was lacking, with most trials not reporting on this outcome." Subsequently in 2017, the Australian government named the Alexander Technique as a practice that would not qualify for insurance subsidy, saying this step would "ensure taxpayer funds are expended appropriately and not directed to therapies lacking evidence".

A review by Aetna last updated in 2021 stated: "Aetna considers the following alternative medicine interventions experimental and investigational because there is inadequate evidence in the peer-reviewed published medical literature of their effectiveness." The Alexander Technique is included in that list.

title: Alexander Technique


text:
Andrea Alciato

Andrea Alciato (8 May 1492 – 12 January 1550), commonly known as Alciati (Andreas Alciatus), was an Italian jurist and writer. He is regarded as the founder of the French school of legal humanists.

Biography
Alciati was born in Alzate Brianza, near Milan, and settled in France in the early 16th century. He displayed great literary skill in his exposition of the laws, and was one of the first to interpret the civil law by the history, languages and literature of antiquity, and to substitute original research for the servile interpretations of the glossators. He published many legal works, and some annotations on Tacitus and accumulated a sylloge of Roman inscriptions from Milan and its territories, as part of his preparation for his history of Milan, written in 1504–05.

Among his several appointments, Alciati taught Law at the University of Bourges between 1529 and 1535. It was Guillaume Budé who encouraged the call to Bourges at the time. Pierre Bayle, in his General Dictionary (article "Alciat"), relates that he greatly increased his salary there, by the "stratagem" of arranging to get a job offer from the University of Bologna and using it as a negotiation point.

Alciati is most famous for his Emblemata, published in dozens of editions from 1531 onward. This collection of short Latin verse texts and accompanying woodcuts created an entire European genre, the emblem book, which attained enormous popularity in continental Europe and Great Britain.

Alciati died at Pavia in 1550.

Works

 * Annotationes in tres libros Codicis (1515)
 * Emblematum libellus (1531)
 * Opera omnia (Basel 1546–49)
 * Rerum Patriae, seu Historiae Mediolanensis, Libri IV (Milan, 1625) a history of Milan, written in 1504–05.
 * De formula Romani Imperii (Basilae: Ioannem Oporinum, 1559, editio princeps)
 * De formula Romani Imperii (Basilae: Ioannem Oporinum, 1559, editio princeps)

Quotation
"Plenitudo potestatis nihil aliud est quam violentia."

title: Andrea Alciato


text:
Apparent magnitude

Apparent magnitude ($m$) is a measure of the brightness of a star or other astronomical object. An object's apparent magnitude depends on its intrinsic luminosity, its distance, and any extinction of the object's light caused by interstellar dust along the line of sight to the observer.

The word magnitude in astronomy, unless stated otherwise, usually refers to a celestial object's apparent magnitude. The magnitude scale dates to before the ancient Roman astronomer Claudius Ptolemy, whose star catalog popularized the system by listing stars from 1st magnitude (brightest) to 6th magnitude (dimmest). The modern scale was mathematically defined in a way to closely match this historical system.

The scale is reverse logarithmic: the brighter an object is, the lower its magnitude number. A difference of 1.0 in magnitude corresponds to a brightness ratio of $$\sqrt[5]{100}$$, or about 2.512. For example, a star of magnitude 2.0 is 2.512 times as bright as a star of magnitude 3.0, 6.31 times as bright as a star of magnitude 4.0, and 100 times as bright as one of magnitude 7.0.

The brightest astronomical objects have negative apparent magnitudes: for example, Venus at −4.2 or Sirius at −1.46. The faintest stars visible with the naked eye on the darkest night have apparent magnitudes of about +6.5, though this varies depending on a person's eyesight and with altitude and atmospheric conditions. The apparent magnitudes of known objects range from the Sun at −26.832 to objects in deep Hubble Space Telescope images of magnitude +31.5.

The measurement of apparent magnitude is called photometry. Photometric measurements are made in the ultraviolet, visible, or infrared wavelength bands using standard passband filters belonging to photometric systems such as the UBV system or the Strömgren uvbyβ system. Measurement in the V-band may be referred to as the apparent visual magnitude.

Absolute magnitude is a related quantity which measures the luminosity that a celestial object emits, rather than its apparent brightness when observed, and is expressed on the same reverse logarithmic scale. Absolute magnitude is defined as the apparent magnitude that a star or object would have if it were observed from a distance of 10 parsec. Therefore, it is of greater use in stellar astrophysics since it refers to a property of a star regardless of how close it is to Earth. But in observational astronomy and popular stargazing, references to "magnitude" are understood to mean apparent magnitude.

Amateur astronomers commonly express the darkness of the sky in terms of limiting magnitude, i.e. the apparent magnitude of the faintest star they can see with the naked eye. This can be useful as a way of monitoring the spread of light pollution.

Apparent magnitude is really a measure of illuminance, which can also be measured in photometric units such as lux.

History
The scale used to indicate magnitude originates in the Hellenistic practice of dividing stars visible to the naked eye into six magnitudes. The brightest stars in the night sky were said to be of first magnitude ($1,602$ = 1), whereas the faintest were of sixth magnitude ($4,800$ = 6), which is the limit of human visual perception (without the aid of a telescope). Each grade of magnitude was considered twice the brightness of the following grade (a logarithmic scale), although that ratio was subjective as no photodetectors existed. This rather crude scale for the brightness of stars was popularized by Ptolemy in his Almagest and is generally believed to have originated with Hipparchus. This cannot be proved or disproved because Hipparchus's original star catalogue is lost. The only preserved text by Hipparchus himself (a commentary to Aratus) clearly documents that he did not have a system to describe brightness with numbers: He always uses terms like "big" or "small", "bright" or "faint" or even descriptions such as "visible at full moon".

In 1856, Norman Robert Pogson formalized the system by defining a first magnitude star as a star that is 100 times as bright as a sixth-magnitude star, thereby establishing the logarithmic scale still in use today. This implies that a star of magnitude $9,100$ is about 2.512 times as bright as a star of magnitude $m + 1$. This figure, the fifth root of 100, became known as Pogson's Ratio. The 1884 Harvard Photometry and 1886 Potsdamer Duchmusterung star catalogs popularized Pogson's ratio, and eventually it became a de facto standard in modern astronomy to describe differences in brightness.

Defining and calibrating what magnitude 0.0 means is difficult, and different types of measurements which detect different kinds of light (possibly by using filters) have different zero points. Pogson's original 1856 paper defined magnitude 6.0 to be the faintest star the unaided eye can see, but the true limit for faintest possible visible star varies depending on the atmosphere and how high a star is in the sky. The Harvard Photometry used an average of 100 stars close to Polaris to define magnitude 5.0. Later, the Johnson UVB photometric system defined multiple types of photometric measurements with different filters, where magnitude 0.0 for each filter is defined to be the average of six stars with the same spectral type as Vega. This was done so the color index of these stars would be 0. Although this system is often called "Vega normalized", Vega is slightly dimmer than the six-star average used to define magnitude 0.0, meaning Vega's magnitude is normalized to 0.03 by definition.

With the modern magnitude systems, brightness is described using Pogson's ratio. In practice magnitude numbers rarely go above 30 before stars become too faint to detect. While Vega is close to magnitude 0, there are four brighter stars in the night sky at visible wavelengths (and more at infrared wavelengths) as well as the bright planets Venus, Mars, and Jupiter, and since brighter means smaller magnitude, these must be described by negative magnitudes. For example, Sirius, the brightest star of the celestial sphere, has a magnitude of −1.4 in the visible. Negative magnitudes for other very bright astronomical objects can be found in the table below.

Astronomers have developed other photometric zero point systems as alternatives to Vega normalized systems. The most widely used is the AB magnitude system, in which photometric zero points are based on a hypothetical reference spectrum having constant flux per unit frequency interval, rather than using a stellar spectrum or blackbody curve as the reference. The AB magnitude zero point is defined such that an object's AB and Vega-based magnitudes will be approximately equal in the V filter band. However, the AB magnitude system is defined assuming an idealized detector measuring only one wavelength of light, while real detectors accept energy from a range of wavelengths.

Measurement
Precision measurement of magnitude (photometry) requires calibration of the photographic or (usually) electronic detection apparatus. This generally involves contemporaneous observation, under identical conditions, of standard stars whose magnitude using that spectral filter is accurately known. Moreover, as the amount of light actually received by a telescope is reduced due to transmission through the Earth's atmosphere, the airmasses of the target and calibration stars must be taken into account. Typically one would observe a few different stars of known magnitude which are sufficiently similar. Calibrator stars close in the sky to the target are favoured (to avoid large differences in the atmospheric paths). If those stars have somewhat different zenith angles (altitudes) then a correction factor as a function of airmass can be derived and applied to the airmass at the target's position. Such calibration obtains the brightness as would be observed from above the atmosphere, where apparent magnitude is defined.

The apparent magnitude scale in astronomy reflects the received power of stars and not their amplitude. Newcomers should consider using the relative brightness measure in astrophotography to adjust exposure times between stars. Apparent magnitude also integrates over the entire object, regardless of its focus, and this needs to be taken into account when scaling exposure times for objects with significant apparent size, like the Sun, Moon and planets. For example, directly scaling the exposure time from the Moon to the Sun works because they are approximately the same size in the sky. However, scaling the exposure from the Moon to Saturn would result in an overexposure if the image of Saturn takes up a smaller area on your sensor than the Moon did (at the same magnification, or more generally, f/#).

Calculations

The dimmer an object appears, the higher the numerical value given to its magnitude, with a difference of 5 magnitudes corresponding to a brightness factor of exactly 100. Therefore, the magnitude $14,000$, in the spectral band $42,000$, would be given by $$m_{x}= -5 \log_{100} \left(\frac {F_x}{F_{x,0}}\right),$$ which is more commonly expressed in terms of common (base-10) logarithms as $$m_{x} = -2.5 \log_{10} \left(\frac {F_x}{F_{x,0}}\right),$$ where $121,000$ is the observed irradiance using spectral filter $340,000$, and $F_{x,0}$ is the reference flux (zero-point) for that photometric filter. Since an increase of 5 magnitudes corresponds to a decrease in brightness by a factor of exactly 100, each magnitude increase implies a decrease in brightness by the factor $$\sqrt[5]{100} \approx 2.512$$ (Pogson's ratio). Inverting the above formula, a magnitude difference $m_{1} − m_{2} = Δm$ implies a brightness factor of $$ \frac{F_2}{F_1} = 100^\frac{\Delta m}{5} = 10^{0.4 \Delta m} \approx 2.512^{\Delta m}.$$

Example: Sun and Moon
What is the ratio in brightness between the Sun and the full Moon?

The apparent magnitude of the Sun is −26.832 (brighter), and the mean magnitude of the full moon is −12.74 (dimmer).

Difference in magnitude: $$ x = m_1 - m_2 = (-12.74) - (-26.832) = 14.09. $$

Brightness factor: $$ v_b = 10^{0.4 x} = 10^{0.4 \times 14.09} \approx 432\,513. $$

The Sun appears to be approximately $m$ times as bright as the full Moon.

Magnitude addition
Sometimes one might wish to add brightness. For example, photometry on closely separated double stars may only be able to produce a measurement of their combined light output. To find the combined magnitude of that double star knowing only the magnitudes of the individual components, this can be done by adding the brightness (in linear units) corresponding to each magnitude. $$ 10^{-m_f \times 0.4} = 10^{-m_1 \times 0.4} + 10^{-m_2 \times 0.4}. $$

Solving for $$m_f$$ yields $$ m_f = -2.5\log_{10} \left(10^{-m_1 \times 0.4} + 10^{-m_2 \times 0.4} \right), $$ where $m$ is the resulting magnitude after adding the brightnesses referred to by $m_{1}$ and $m_{2}$.

Apparent bolometric magnitude
While magnitude generally refers to a measurement in a particular filter band corresponding to some range of wavelengths, the apparent or absolute bolometric magnitude (mbol) is a measure of an object's apparent or absolute brightness integrated over all wavelengths of the electromagnetic spectrum (also known as the object's irradiance or power, respectively). The zero point of the apparent bolometric magnitude scale is based on the definition that an apparent bolometric magnitude of 0 mag is equivalent to a received irradiance of 2.518×10−8 watts per square metre (W·m−2).

Absolute magnitude
While apparent magnitude is a measure of the brightness of an object as seen by a particular observer, absolute magnitude is a measure of the intrinsic brightness of an object. Flux decreases with distance according to an inverse-square law, so the apparent magnitude of a star depends on both its absolute brightness and its distance (and any extinction). For example, a star at one distance will have the same apparent magnitude as a star four times as bright at twice that distance. In contrast, the intrinsic brightness of an astronomical object, does not depend on the distance of the observer or any extinction.

The absolute magnitude $m$, of a star or astronomical object is defined as the apparent magnitude it would have as seen from a distance of 10 pc. The absolute magnitude of the Sun is 4.83 in the V band (visual), 4.68 in the Gaia satellite's G band (green) and 5.48 in the B band (blue).

In the case of a planet or asteroid, the absolute magnitude $m$ rather means the apparent magnitude it would have if it were 1 AU from both the observer and the Sun, and fully illuminated at maximum opposition (a configuration that is only theoretically achievable, with the observer situated on the surface of the Sun).

Standard reference values
The magnitude scale is a reverse logarithmic scale. A common misconception is that the logarithmic nature of the scale is because the human eye itself has a logarithmic response. In Pogson's time this was thought to be true (see Weber–Fechner law), but it is now believed that the response is a power law.

Magnitude is complicated by the fact that light is not monochromatic. The sensitivity of a light detector varies according to the wavelength of the light, and the way it varies depends on the type of light detector. For this reason, it is necessary to specify how the magnitude is measured for the value to be meaningful. For this purpose the UBV system is widely used, in which the magnitude is measured in three different wavelength bands: U (centred at about 350 nm, in the near ultraviolet), B (about 435 nm, in the blue region) and V (about 555 nm, in the middle of the human visual range in daylight). The V band was chosen for spectral purposes and gives magnitudes closely corresponding to those seen by the human eye. When an apparent magnitude is discussed without further qualification, the V magnitude is generally understood.

Because cooler stars, such as red giants and red dwarfs, emit little energy in the blue and UV regions of the spectrum, their power is often under-represented by the UBV scale. Indeed, some L and T class stars have an estimated magnitude of well over 100, because they emit extremely little visible light, but are strongest in infrared.

Measures of magnitude need cautious treatment and it is extremely important to measure like with like. On early 20th century and older orthochromatic (blue-sensitive) photographic film, the relative brightnesses of the blue supergiant Rigel and the red supergiant Betelgeuse irregular variable star (at maximum) are reversed compared to what human eyes perceive, because this archaic film is more sensitive to blue light than it is to red light. Magnitudes obtained from this method are known as photographic magnitudes, and are now considered obsolete.

For objects within the Milky Way with a given absolute magnitude, 5 is added to the apparent magnitude for every tenfold increase in the distance to the object. For objects at very great distances (far beyond the Milky Way), this relationship must be adjusted for redshifts and for non-Euclidean distance measures due to general relativity.

For planets and other Solar System bodies, the apparent magnitude is derived from its phase curve and the distances to the Sun and observer.

List of apparent magnitudes
Some of the listed magnitudes are approximate. Telescope sensitivity depends on observing time, optical bandpass, and interfering light from scattering and airglow.

title: Apparent magnitude


text:
Absolute magnitude

In astronomy, absolute magnitude ($M$) is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it were viewed from a distance of exactly 10 pc, without extinction (or dimming) of its light due to absorption by interstellar matter and cosmic dust. By hypothetically placing all objects at a standard reference distance from the observer, their luminosities can be directly compared among each other on a magnitude scale. For Solar System bodies that shine in reflected light, a different definition of absolute magnitude (H) is used, based on a standard reference distance of one astronomical unit.

Absolute magnitudes of stars generally range from approximately −10 to +20. The absolute magnitudes of galaxies can be much lower (brighter).

The more luminous an object, the smaller the numerical value of its absolute magnitude. A difference of 5 magnitudes between the absolute magnitudes of two objects corresponds to a ratio of 100 in their luminosities, and a difference of n magnitudes in absolute magnitude corresponds to a luminosity ratio of 100n/5. For example, a star of absolute magnitude MV = 3.0 would be 100 times as luminous as a star of absolute magnitude MV = 8.0 as measured in the V filter band. The Sun has absolute magnitude MV = +4.83. Highly luminous objects can have negative absolute magnitudes: for example, the Milky Way galaxy has an absolute B magnitude of about −20.8.

As with all astronomical magnitudes, the absolute magnitude can be specified for different wavelength ranges corresponding to specified filter bands or passbands; for stars a commonly quoted absolute magnitude is the absolute visual magnitude, which uses the visual (V) band of the spectrum (in the UBV photometric system). Absolute magnitudes are denoted by a capital M, with a subscript representing the filter band used for measurement, such as MV for absolute magnitude in the V band.

An object's absolute bolometric magnitude (Mbol) represents its total luminosity over all wavelengths, rather than in a single filter band, as expressed on a logarithmic magnitude scale. To convert from an absolute magnitude in a specific filter band to absolute bolometric magnitude, a bolometric correction (BC) is applied.

Stars and galaxies
In stellar and galactic astronomy, the standard distance is 10 parsecs (about 32.616 light-years, 308.57 petameters or 308.57 trillion kilometres). A star at 10 parsecs has a parallax of 0.1″ (100 milliarcseconds). Galaxies (and other extended objects) are much larger than 10 parsecs, their light is radiated over an extended patch of sky, and their overall brightness cannot be directly observed from relatively short distances, but the same convention is used. A galaxy's magnitude is defined by measuring all the light radiated over the entire object, treating that integrated brightness as the brightness of a single point-like or star-like source, and computing the magnitude of that point-like source as it would appear if observed at the standard 10 parsecs distance. Consequently, the absolute magnitude of any object equals the apparent magnitude it would have if it were 10 parsecs away.

Some stars visible to the naked eye have such a low absolute magnitude that they would appear bright enough to outshine the planets and cast shadows if they were at 10 parsecs from the Earth. Examples include Rigel (−7.8), Deneb (−8.4), Naos (−6.2), and Betelgeuse (−5.8). For comparison, Sirius has an absolute magnitude of only 1.4, which is still brighter than the Sun, whose absolute visual magnitude is 4.83. The Sun's absolute bolometric magnitude is set arbitrarily, usually at 4.75. Absolute magnitudes of stars generally range from approximately −10 to +20. The absolute magnitudes of galaxies can be much lower (brighter). For example, the giant elliptical galaxy M87 has an absolute magnitude of −22 (i.e. as bright as about 60,000 stars of magnitude −10). Some active galactic nuclei (quasars like CTA-102) can reach absolute magnitudes in excess of −32, making them the most luminous persistent objects in the observable universe, although these objects can vary in brightness over astronomically short timescales. At the extreme end, the optical afterglow of the gamma ray burst GRB 080319B reached, according to one paper, an absolute r magnitude brighter than −38 for a few tens of seconds.

Apparent magnitude
The Greek astronomer Hipparchus established a numerical scale to describe the brightness of each star appearing in the sky. The brightest stars in the sky were assigned an apparent magnitude $m = 1$, and the dimmest stars visible to the naked eye are assigned $m = 6$. The difference between them corresponds to a factor of 100 in brightness. For objects within the immediate neighborhood of the Sun, the absolute magnitude $M$ and apparent magnitude $m$ from any distance $d$ (in parsecs, with 1 pc = 3.2616 light-years) are related by $$ 100^{\frac{m-M}{5}}=\frac{F_{10}}{F} = \left(\frac{d}{10\;\mathrm{pc}}\right)^{2}, $$ where $F$ is the radiant flux measured at distance $d$ (in parsecs), $F_{10}$ the radiant flux measured at distance $10 pc$. Using the common logarithm, the equation can be written as $$ M = m - 5 \log_{10}(d_\text{pc})+5 = m - 5 \left(\log_{10}d_\text{pc}-1\right),$$ where it is assumed that extinction from gas and dust is negligible. Typical extinction rates within the Milky Way galaxy are 1 to 2 magnitudes per kiloparsec, when dark clouds are taken into account.

For objects at very large distances (outside the Milky Way) the luminosity distance $d_{L}$ (distance defined using luminosity measurements) must be used instead of $d$, because the Euclidean approximation is invalid for distant objects. Instead, general relativity must be taken into account. Moreover, the cosmological redshift complicates the relationship between absolute and apparent magnitude, because the radiation observed was shifted into the red range of the spectrum. To compare the magnitudes of very distant objects with those of local objects, a K correction might have to be applied to the magnitudes of the distant objects.

The absolute magnitude $M$ can also be written in terms of the apparent magnitude $m$ and stellar parallax $p$: $$ M = m + 5 \left(\log_{10}p+1\right),$$ or using apparent magnitude $m$ and distance modulus $μ$: $$ M = m - \mu.$$

Examples
Rigel has a visual magnitude $m_{V}$ of 0.12 and distance of about 860 light-years: $$M_\mathrm{V} = 0.12 - 5 \left(\log_{10} \frac{860}{3.2616} - 1 \right) = -7.0.$$

Vega has a parallax $p$ of 0.129″, and an apparent magnitude $m_{V}$ of 0.03: $$M_\mathrm{V} = 0.03 + 5 \left(\log_{10}{0.129} + 1\right) = +0.6.$$

The Black Eye Galaxy has a visual magnitude $m_{V}$ of 9.36 and a distance modulus $μ$ of 31.06: $$M_\mathrm{V} = 9.36 - 31.06 = -21.7.$$

Bolometric magnitude
The absolute bolometric magnitude ($M_{bol}$) takes into account electromagnetic radiation at all wavelengths. It includes those unobserved due to instrumental passband, the Earth's atmospheric absorption, and extinction by interstellar dust. It is defined based on the luminosity of the stars. In the case of stars with few observations, it must be computed assuming an effective temperature.

Classically, the difference in bolometric magnitude is related to the luminosity ratio according to: $$M_\mathrm{bol,\star} - M_\mathrm{bol,\odot} = -2.5 \log_{10} \left(\frac{L_\star}{L_\odot}\right)$$ which makes by inversion: $$\frac{L_\star}{L_\odot} = 10^{0.4\left(M_\mathrm{bol,\odot} - M_\mathrm{bol,\star}\right)}$$ where
 * $L_{⊙}$ is the Sun's luminosity (bolometric luminosity)
 * $L_{★}$ is the star's luminosity (bolometric luminosity)
 * $M_{bol,⊙}$ is the bolometric magnitude of the Sun
 * $M_{bol,★}$ is the bolometric magnitude of the star.

In August 2015, the International Astronomical Union passed Resolution B2 defining the zero points of the absolute and apparent bolometric magnitude scales in SI units for power (watts) and irradiance (W/m2), respectively. Although bolometric magnitudes had been used by astronomers for many decades, there had been systematic differences in the absolute magnitude-luminosity scales presented in various astronomical references, and no international standardization. This led to systematic differences in bolometric corrections scales. Combined with incorrect assumed absolute bolometric magnitudes for the Sun, this could lead to systematic errors in estimated stellar luminosities (and other stellar properties, such as radii or ages, which rely on stellar luminosity to be calculated).

Resolution B2 defines an absolute bolometric magnitude scale where $M_{bol} = 0$ corresponds to luminosity $L_{0} = 3.013 W$, with the zero point luminosity $L_{0}$ set such that the Sun (with nominal luminosity $3.828 W$) corresponds to absolute bolometric magnitude $M_{bol,⊙} = 4.74$. Placing a radiation source (e.g. star) at the standard distance of 10 parsecs, it follows that the zero point of the apparent bolometric magnitude scale $m_{bol} = 0$ corresponds to irradiance $f_{0} = 2.518 W/m^{2}$. Using the IAU 2015 scale, the nominal total solar irradiance ("solar constant") measured at 1 astronomical unit ($1,361 W/m^{2}$) corresponds to an apparent bolometric magnitude of the Sun of $m_{bol,⊙} = −26.832$.

Following Resolution B2, the relation between a star's absolute bolometric magnitude and its luminosity is no longer directly tied to the Sun's (variable) luminosity: $$M_\mathrm{bol} = -2.5 \log_{10} \frac{L_\star}{L_0} \approx -2.5 \log_{10} L_\star + 71.197425$$ where
 * $L_{★}$ is the star's luminosity (bolometric luminosity) in watts
 * $L_{0}$ is the zero point luminosity $3.013 W$
 * $M_{bol}$ is the bolometric magnitude of the star

The new IAU absolute magnitude scale permanently disconnects the scale from the variable Sun. However, on this SI power scale, the nominal solar luminosity corresponds closely to $M_{bol} = 4.74$, a value that was commonly adopted by astronomers before the 2015 IAU resolution.

The luminosity of the star in watts can be calculated as a function of its absolute bolometric magnitude $M_{bol}$ as: $$L_\star = L_0 10^{-0.4 M_\mathrm{bol}}$$ using the variables as defined previously.

Solar System bodies ($H$)
For planets and asteroids, a definition of absolute magnitude that is more meaningful for non-stellar objects is used. The absolute magnitude, commonly called $$H$$, is defined as the apparent magnitude that the object would have if it were one astronomical unit (AU) from both the Sun and the observer, and in conditions of ideal solar opposition (an arrangement that is impossible in practice). Because Solar System bodies are illuminated by the Sun, their brightness varies as a function of illumination conditions, described by the phase angle. This relationship is referred to as the phase curve. The absolute magnitude is the brightness at phase angle zero, an arrangement known as opposition, from a distance of one AU.

Apparent magnitude
The absolute magnitude $$H$$ can be used to calculate the apparent magnitude $$m$$ of a body. For an object reflecting sunlight, $$H$$ and $$m$$ are connected by the relation $$m = H + 5 \log_{10}{\left(\frac{d_{BS} d_{BO}}{d_0^2}\right)} - 2.5 \log_{10}{q(\alpha)},$$ where $$\alpha$$ is the phase angle, the angle between the body-Sun and body–observer lines. $$q(\alpha)$$ is the phase integral (the integration of reflected light; a number in the 0 to 1 range).

By the law of cosines, we have: $$\cos{\alpha} = \frac{ d_\mathrm{BO}^2 + d_\mathrm{BS}^2 - d_\mathrm{OS}^2 } {2 d_\mathrm{BO} d_\mathrm{BS}}.$$

Distances:
 * $d_{BO}$ is the distance between the body and the observer
 * $d_{BS}$ is the distance between the body and the Sun
 * $d_{OS}$ is the distance between the observer and the Sun
 * $d_{0}$, a unit conversion factor, is the constant 1 AU, the average distance between the Earth and the Sun

Approximations for phase integral
The value of $$q(\alpha)$$ depends on the properties of the reflecting surface, in particular on its roughness. In practice, different approximations are used based on the known or assumed properties of the surface. The surfaces of terrestrial planets are generally more difficult to model than those of gaseous planets, the latter of which have smoother visible surfaces.

Planets as diffuse spheres
Planetary bodies can be approximated reasonably well as ideal diffuse reflecting spheres. Let $$\alpha$$ be the phase angle in degrees, then $$q(\alpha) = \frac23 \left(\left(1-\frac{\alpha}{180^{\circ}}\right)\cos{\alpha}+\frac{1}{\pi}\sin{\alpha}\right).$$ A full-phase diffuse sphere reflects two-thirds as much light as a diffuse flat disk of the same diameter. A quarter phase ($$\alpha = 90^{\circ}$$) has $\frac{1}{\pi}$ as much light as full phase ($$\alpha = 0^{\circ}$$).

By contrast, a diffuse disk reflector model is simply $$q(\alpha) = \cos{\alpha}$$, which isn't realistic, but it does represent the opposition surge for rough surfaces that reflect more uniform light back at low phase angles.

The definition of the geometric albedo $$p$$, a measure for the reflectivity of planetary surfaces, is based on the diffuse disk reflector model. The absolute magnitude $$H$$, diameter $$D$$ (in kilometers) and geometric albedo $$p$$ of a body are related by $$D = \frac{1329}{\sqrt{p}} \times 10^{-0.2H} \mathrm{km},$$ or equivalently, $$H = 5\log_{10}{\frac{1329}{D\sqrt{p}}}.$$

Example: The Moon's absolute magnitude $$H$$ can be calculated from its diameter $$D=3474\text{ km}$$ and geometric albedo $$p = 0.113$$: $$H = 5\log_{10}{\frac{1329}{3474\sqrt{0.113}}} = +0.28.$$ We have $$d_{BS}=1\text{ AU}$$, $$d_{BO}=384400\text{ km}=0.00257\text{ AU}.$$ At quarter phase, $q(\alpha)\approx \frac{2}{3\pi}$ (according to the diffuse reflector model), this yields an apparent magnitude of $$m = +0.28+5\log_{10}{\left(1\cdot0.00257\right)} - 2.5\log_{10}{\left(\frac{2}{3\pi}\right)} = -10.99.$$ The actual value is somewhat lower than that, $$m=-10.0.$$ This is not a good approximation, because the phase curve of the Moon is too complicated for the diffuse reflector model. A more accurate formula is given in the following section.

More advanced models
Because Solar System bodies are never perfect diffuse reflectors, astronomers use different models to predict apparent magnitudes based on known or assumed properties of the body. For planets, approximations for the correction term $$-2.5\log_{10}{q(\alpha)}$$ in the formula for $m$ have been derived empirically, to match observations at different phase angles. The approximations recommended by the Astronomical Almanac are (with $$\alpha$$ in degrees):

Here $$\beta$$ is the effective inclination of Saturn's rings (their tilt relative to the observer), which as seen from Earth varies between 0° and 27° over the course of one Saturn orbit, and $$\phi'$$ is a small correction term depending on Uranus' sub-Earth and sub-solar latitudes. $$t$$ is the Common Era year. Neptune's absolute magnitude is changing slowly due to seasonal effects as the planet moves along its 165-year orbit around the Sun, and the approximation above is only valid after the year 2000. For some circumstances, like $$\alpha \ge 179^{\circ}$$ for Venus, no observations are available, and the phase curve is unknown in those cases. The formula for the Moon is only applicable to the near side of the Moon, the portion that is visible from the Earth.

Example 1: On 1 January 2019, Venus was $$d_{BS}=0.719\text{ AU}$$ from the Sun, and $$d_{BO} = 0.645\text{ AU}$$ from Earth, at a phase angle of $$\alpha=93.0^{\circ}$$ (near quarter phase). Under full-phase conditions, Venus would have been visible at $$m=-4.384+5\log_{10}{\left(0.719 \cdot 0.645\right)}=-6.09.$$ Accounting for the high phase angle, the correction term above yields an actual apparent magnitude of $$m = -6.09 + \left(-1.044 \times 10^{-3} \cdot 93.0 + 3.687\times10^{-4} \cdot 93.0^{2} - 2.814 \times 10^{-6} \cdot 93.0^{3} + 8.938 \times 10^{-9} \cdot 93.0^{4}\right) = -4.59.$$ This is close to the value of $$m=-4.62$$ predicted by the Jet Propulsion Laboratory.

Example 2: At first quarter phase, the approximation for the Moon gives $-2.5\log_{10}{q(90^{\circ})}=2.71.$ With that, the apparent magnitude of the Moon is $m = +0.28+5\log_{10}{\left(1\cdot0.00257\right)}+2.71= -9.96,$  close to the expected value of about $$-10.0$$. At last quarter, the Moon is about 0.06 mag fainter than at first quarter, because that part of its surface has a lower albedo.

Earth's albedo varies by a factor of 6, from 0.12 in the cloud-free case to 0.76 in the case of altostratus cloud. The absolute magnitude in the table corresponds to an albedo of 0.434. Due to the variability of the weather, Earth's apparent magnitude cannot be predicted as accurately as that of most other planets.

Asteroids
If an object has an atmosphere, it reflects light more or less isotropically in all directions, and its brightness can be modelled as a diffuse reflector. Bodies with no atmosphere, like asteroids or moons, tend to reflect light more strongly to the direction of the incident light, and their brightness increases rapidly as the phase angle approaches $$0^{\circ}$$. This rapid brightening near opposition is called the opposition effect. Its strength depends on the physical properties of the body's surface, and hence it differs from asteroid to asteroid.

In 1985, the IAU adopted the semi-empirical $$HG$$-system, based on two parameters $$H$$ and $$G$$ called absolute magnitude and slope, to model the opposition effect for the ephemerides published by the Minor Planet Center. $$m = H + 5\log_{10}{\left(\frac{d_{BS}d_{BO}}{d_{0}^{2}}\right)}-2.5\log_{10}{q(\alpha)},$$

where
 * the phase integral is $$q(\alpha)=\left(1-G\right)\phi_{1}\left(\alpha\right)+G\phi_{2}\left(\alpha\right)$$ and
 * $\phi_{i}\left(\alpha\right) = \exp{\left(-A_i \left(\tan{\frac{\alpha}{2}}\right)^{B_i}\right)}$ for $$i = 1$$ or $$2$$, $$A_{1}=3.332$$, $$A_{2}=1.862$$, $$B_{1}=0.631$$ and $$B_2 = 1.218$$.

This relation is valid for phase angles $$\alpha < 120^{\circ}$$, and works best when $$\alpha < 20^{\circ}$$.

The slope parameter $$G$$ relates to the surge in brightness, typically $0.3 mag$, when the object is near opposition. It is known accurately only for a small number of asteroids, hence for most asteroids a value of $$G=0.15$$ is assumed. In rare cases, $$G$$ can be negative. An example is 101955 Bennu, with $$G=-0.08$$.

In 2012, the $$HG$$-system was officially replaced by an improved system with three parameters $$H$$, $$G_1$$ and $$G_2$$, which produces more satisfactory results if the opposition effect is very small or restricted to very small phase angles. However, as of 2022, this $$H G_1 G_2$$-system has not been adopted by either the Minor Planet Center nor Jet Propulsion Laboratory.

The apparent magnitude of asteroids varies as they rotate, on time scales of seconds to weeks depending on their rotation period, by up to $$2\text{ mag}$$ or more. In addition, their absolute magnitude can vary with the viewing direction, depending on their axial tilt. In many cases, neither the rotation period nor the axial tilt are known, limiting the predictability. The models presented here do not capture those effects.

Cometary magnitudes
The brightness of comets is given separately as total magnitude ($$m_{1}$$, the brightness integrated over the entire visible extend of the coma) and nuclear magnitude ($$m_{2}$$, the brightness of the core region alone). Both are different scales than the magnitude scale used for planets and asteroids, and can not be used for a size comparison with an asteroid's absolute magnitude $H$.

The activity of comets varies with their distance from the Sun. Their brightness can be approximated as $$m_{1} = M_{1} + 2.5\cdot K_{1}\log_{10}{\left(\frac{d_{BS}}{d_0}\right)} + 5\log_{10}{\left(\frac{d_{BO}}{d_0}\right)}$$ $$m_{2} = M_{2} + 2.5\cdot K_{2}\log_{10}{\left(\frac{d_{BS}}{d_0}\right)} + 5\log_{10}{\left(\frac{d_{BO}}{d_0}\right)},$$ where $$m_{1,2}$$ are the total and nuclear apparent magnitudes of the comet, respectively, $$M_{1,2}$$ are its "absolute" total and nuclear magnitudes, $$d_{BS}$$ and $$d_{BO}$$ are the body-sun and body-observer distances, $$d_{0}$$ is the Astronomical Unit, and $$K_{1,2}$$ are the slope parameters characterising the comet's activity. For $$K=2$$, this reduces to the formula for a purely reflecting body (showing no cometary activity).

For example, the lightcurve of comet C/2011 L4 (PANSTARRS) can be approximated by $$M_{1}=5.41\text{, }K_{1}=3.69.$$ On the day of its perihelion passage, 10 March 2013, comet PANSTARRS was $$0.302\text{ AU}$$ from the Sun and $$1.109\text{ AU}$$ from Earth. The total apparent magnitude $$m_{1}$$ is predicted to have been $$m_1 = 5.41 + 2.5\cdot3.69\cdot\log_{10}{\left(0.302\right)}+5\log_{10}{\left(1.109\right)} = +0.8$$ at that time. The Minor Planet Center gives a value close to that, $$m_{1} = +0.5$$.

The absolute magnitude of any given comet can vary dramatically. It can change as the comet becomes more or less active over time or if it undergoes an outburst. This makes it difficult to use the absolute magnitude for a size estimate. When comet 289P/Blanpain was discovered in 1819, its absolute magnitude was estimated as $$M_{1} = 8.5$$. It was subsequently lost and was only rediscovered in 2003. At that time, its absolute magnitude had decreased to $$M_{1} = 22.9$$, and it was realised that the 1819 apparition coincided with an outburst. 289P/Blanpain reached naked eye brightness (5–8 mag) in 1819, even though it is the comet with the smallest nucleus that has ever been physically characterised, and usually doesn't become brighter than 18 mag.

For some comets that have been observed at heliocentric distances large enough to distinguish between light reflected from the coma, and light from the nucleus itself, an absolute magnitude analogous to that used for asteroids has been calculated, allowing to estimate the sizes of their nuclei.

Meteors
For a meteor, the standard distance for measurement of magnitudes is at an altitude of 100 km at the observer's zenith.

title: Absolute magnitude