![]() | This ![]() It is of interest to the following WikiProjects: | |||||||||||||||||||||||||||
|
It seems out of place to have such an extensive listing of objects. Perhaps this table should only include truly 'notable' objects, and have its own page (or just link to a website with a similar table) for the extended version? All Clues Key ( talk) 02:20, 15 September 2012 (UTC)
How is this related, if at all, to photometric reductions? ~jp
This article is quite poorly organised and in some places poorly explained. For a relatively important atronomy article it is a bit disappointing. 86.160.222.250 ( talk) 21:04, 18 March 2013 (UTC)
The explicit relationship between apparent magnitude, m, and power flux in watts per square meter, F, when m and F pertain to the same bandpass, is
m = −2.5 log F − 18.98224
Example. The sun's bolometric apparent magnitude, as seen from Earth, is −26.8167
m = −26.8167
F = 10^[−0.4(m + 18.98224)]
F = 1360.8 watts per square meter
50.110.104.0 ( talk) 12:35, 6 March 2024 (UTC)
While the extensive table has its uses (discussed above), readers have to scroll down many pages to find formulae to calculate magnitude. As the table mainly provides examples, I think it's reasonable to move it to the bottom to detract from the rest of the page. cmɢʟee ୯ ͡° ̮د ͡° ੭ 11:57, 13 August 2013 (UTC)
Since a superbolide, as in a very bright meteor, or a "superbolid meteor", is defined as a bolide of high apparent magnitude (see Wiktionary on "superbolide"), I wonder if anyone has a scholarly source for at what magnitude a bolide is no longer a bolide and becomes a superbolide? Need it be brighter than the Sun? (App. Mag. approx. equal to -26) Or what? N2e ( talk) 04:40, 21 November 2013 (UTC)
I removed a messed up part of a sentence. One part of what I removed said, "and then switched to using tabulated zero points" but I could find nothing using a Google search but pages that quoted this Wikipedia article. No one but a specially trained astronomer knows what a "tabulated zero points" is. Another part of what I removed was an external http reference, that was a dead link, leading to a page with nothing on it. If you have a reference to "tabulated zero points" and can explain what they are, in plain, non-technical, English, please do. I am really curious. Nick Beeson ( talk) 21:25, 24 February 2015 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Apparent magnitude. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{
Sourcecheck}}
).
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 14:23, 16 October 2016 (UTC)
If true, could we note somewhere that 5 magnitudes fainter implies 10 times further away (since it is used in distance modulus) ? - Rod57 ( talk) 19:22, 16 January 2017 (UTC)
The cite seems to say limiting magnitude 31.2 - it would help to have a quote for the 31.5 in the footnote, a search of the paper for the number 31.5 turns up a blank. Is it a typo? Robert Walker ( talk) 10:01, 20 May 2018 (UTC)
There are many problems with this article page that need significant improvements or update. Fixes include:
I have attempted an improvement in the Introduction, but from the fragmentary nature of the article's text is near impossible to repair.
History section
The History section is very confusing and is poorly cited. Various contradictions appear with Magnitude (astronomy)#History
Absolute magnitude section
Most of this should be simplified, summarised and condensed. It should plainly mention that apparent magnitude is independent of distance, while absolute magnitude is based on an arbitrarily set distance of 10 parsec.
Table of examples
Most of this listing is theoretical and difficult to understand. Suggest making a shorter Table with atypical values for bright star and planets. he labels should b changed from "planet Mercury" to Mercury (planet) which would make this more readable. (or even a separate column?)
NOTE: @ Lithopsian: There also needs to be an explanation of usage. Many articles have odd usage, like "magnitude 6.0" or or a " the components are magnitudes 4.0 and 5.1 respectively" [3] If magnitude is the unit measure of brightness, then the value must be followed by the unit measure. e.g, "6th magnitude' or "6.0v magnitude" or a "double star is 4.5v and 5.6v magnitude" must be correct. Using the plural of magnitude is also incorrect usage in this respect. Better usage would be "magnitude of 6.0" I find few examples of the reverse usage in the popular or astronomical literature. The claim "correct usage of magnitude as a unit," must be problematic? RfC??
Arianewiki1 ( talk) 08:27, 19 May 2019 (UTC)
The one thing that the Standard reference values section doesn't seem to discuss is standard reference values, although there is a table of standard fluxes in various passbands. The text of the section is just general chit-chat, very poorly-referenced. I can't think of a name for it. Should it just be dumped and written from scratch? Chopped up and farmed out to other places like the history section? Lithopsian ( talk) 19:26, 7 June 2019 (UTC)
The article mentions that magnitude determination was crude and subjective before the invention of photodetectors, but I do wonder if there would be a way of classifying things in a repeatable fashion to a certain arbitrary level of precision - say, 0.1 on a log2 scale? (Which would give us less than 100 steps from "too faint to see" up to "brightest known object other than the sun and moon", and it's entirely possible to rank printed or on-screen greyscales more finely than that, by eye, so long as you can compare between them, and the dynamic brightness of a VDU or piece of paper is far less than that of natural light)
There are various methods I could think of... for example, the earliest hour that a star becomes visible after sunset, especially if you make repeat measurements at the summer and/or winter solstice and equinoxes, using some way of excluding visual pollution from the horizon or nearby dwellings (e.g. the classic lensless paper tube "telescope", or the makeshift observatory of a building missing its roof - the latter of which, along with a parabolic support made of bricks, was something actually used by pre-optical-glass astronomers, especially in Arabia). Date and time was something much more easily measured even in antiquity, and the motion of the stars and planets themselves was used to measure such. Your determination could then be checked by seeing whether certain well known benchmark stars were or were not yet visible, and a ranked list drawn up and refined over time. Once you had sufficient entries, it would be enough to simply wait for the first moment the star / planet of interest became visible, and quickly check to see which other stars off the list in the general predicted neighbourhood were already visible, in order to add the as-yet unranked one into the catalogue in the right place...
Maybe it wouldn't be absolutely accurate, or mathematically precise other than in terms of direct comparison, but for the type of astronomy that was even possible (and thought relating to it) in the pre-telescopic age, it would likely have been more than sufficient, and still fairly scientifically valid. Astronomers of old weren't entirely stupid, after all, just limited in the equipment they had available. It's not beyond the realm of imagination to consider they might have come up with some clever scheme to repeatably determine the objective brightness of a star (after all, I just pulled one out of my ass, and I haven't had a lifetime of pondering on the meaning of the universe in an age long before multichannel TV and the internet); the brightening and darkening of the sky, on clear nights, in an age before any meaningful atmospheric or indeed much light pollution, would have been like the apocryphal clockwork, and something you could set your biological photometer by. 146.199.60.87 ( talk) 19:41, 11 August 2019 (UTC)
@ Lithopsian: Your last edit was a valiant attempt, but now you have "The magnitude scale is logarithmic..." while the next sentence begins "The magnitude scale is reverse logarithmic...". Your comment "not entirely convinced it is better" is well said :) Definitely a tough topic to introduce without confusing people. Might've been better to just revert the unregistered user's edit; what was there before was much clearer, in my opinion. Assambrew ( talk) 08:19, 16 October 2020 (UTC)
Just noticed that "apparent brightness," though redirecting here, isn't talked about at all, although the article seems to use it to mean something specific. Perhaps it could be brought up (or removed)? – LogStar100 ( talk) 19:24, 3 February 2021 (UTC)
The table "Standard apparent magnitudes and fluxes for typical bands" lists various bands. Jy column at first appears to follow the spectral black body curve, as would be expected, since the units are per Hz, and agnostic of the band width, however the Jy values for bands g,r,i,z are inconsistent with the above bands and appear to be in error.
This seems to me a little bit academic, because when Mercury is at superior conjunction, you can't see it. The same thing goes for the minimum brightness of Mercury (around inferior conjunction). Realistically, the most useful apparent magnitude of Mercury is going to be that around maximum elongation, right? Double sharp ( talk) 09:13, 2 October 2021 (UTC)
The table listing "Number of stars (other than the Sun) brighter than apparent magnitude in the night sky" seems not correct. If the number 9100 is correct, the numbers at the top should also include the magnitude on the respective rows and the stars on rows above, as the number 9100 from Bright Star Catalogue implies. That is, the second row in that column should say 5 rather than 4. (Maybe other lines should also be changed.) Fomalhaut76 ( talk) 15:25, 20 March 2023 (UTC)
It is stated that the magnitude scale can be related to the decibel scale, as one magnitude step equals exactly 4 dB. I can see that this is mathematically correct, but is there anyone actually using decibel in this way? If no source to actual use of decibel related to apparent magnitude, then the statement should be deleted, as it does not convey any useful information. JakobT ( talk) 08:13, 9 August 2023 (UTC)
It would be great if someone could add into the list the apparent magnitudes of Jupiter when seen from certain moons, a "full Jupiter" e.g. from Metis, the Galilean moons or Himalia. 2001:4BC9:1F98:112C:B897:9213:2412:1F13 ( talk) 17:07, 8 October 2023 (UTC)
Hi! Both this page and Magnitude (astronomy) claim that Pogson defined magnitude zero to be based on Polaris = 2.0, and then astronomers switched to Vega = magnitude 0.0. I was curious about the history of magnitude, and fell down a rabbit hole of research, and then an wrote an article called The Cursed History of Star Brightness [5] about my findings: I tracked down Pogson's original paper, and it actually defined magnitude 6.0. In fact, this page's history of magnitude section contains some errors in the large citation-free paragraphs.
Magnitude (astronomy) makes the same claim that astronomers defined magnitudes using Vega = 0.0, but cites page 182 of a book. That book, as seen on https://books.google.com/books?id=Ps_6zjUCR3wC&q=182#v=snippet&q=182&f=false here, does mention Vega's variability several pages after page 182, but it describes a model for the spectrum of Vega from 1991, far after Johnson's system was invented, and doesn't say that the model is used to calibrate magnitude zero.
This page also claimed that "Therefore, the magnitude scale was extrapolated to all wavelengths on the basis of the black-body radiation curve for an ideal stellar surface at 11000 K uncontaminated by circumstellar radiation". It cites https://archive.today/20121204144725/http://www.astro.utoronto.ca/~patton/astro/mags.html, but that website doesn't mention anything about a black body spectrum. I've removed it in my edit, but if anyone does have a source for that claim I'd love to see it.
Since I found many primary sources while doing research for my article, I've edited this page to reflect what I understand is the correct history. If any of you Wikipedia editors have any comments, suggestions on how to rewrite it, or sources about the history of magnitude, please let me know! Explanaria ( talk) 20:28, 23 May 2024 (UTC)
![]() | This ![]() It is of interest to the following WikiProjects: | |||||||||||||||||||||||||||
|
It seems out of place to have such an extensive listing of objects. Perhaps this table should only include truly 'notable' objects, and have its own page (or just link to a website with a similar table) for the extended version? All Clues Key ( talk) 02:20, 15 September 2012 (UTC)
How is this related, if at all, to photometric reductions? ~jp
This article is quite poorly organised and in some places poorly explained. For a relatively important atronomy article it is a bit disappointing. 86.160.222.250 ( talk) 21:04, 18 March 2013 (UTC)
The explicit relationship between apparent magnitude, m, and power flux in watts per square meter, F, when m and F pertain to the same bandpass, is
m = −2.5 log F − 18.98224
Example. The sun's bolometric apparent magnitude, as seen from Earth, is −26.8167
m = −26.8167
F = 10^[−0.4(m + 18.98224)]
F = 1360.8 watts per square meter
50.110.104.0 ( talk) 12:35, 6 March 2024 (UTC)
While the extensive table has its uses (discussed above), readers have to scroll down many pages to find formulae to calculate magnitude. As the table mainly provides examples, I think it's reasonable to move it to the bottom to detract from the rest of the page. cmɢʟee ୯ ͡° ̮د ͡° ੭ 11:57, 13 August 2013 (UTC)
Since a superbolide, as in a very bright meteor, or a "superbolid meteor", is defined as a bolide of high apparent magnitude (see Wiktionary on "superbolide"), I wonder if anyone has a scholarly source for at what magnitude a bolide is no longer a bolide and becomes a superbolide? Need it be brighter than the Sun? (App. Mag. approx. equal to -26) Or what? N2e ( talk) 04:40, 21 November 2013 (UTC)
I removed a messed up part of a sentence. One part of what I removed said, "and then switched to using tabulated zero points" but I could find nothing using a Google search but pages that quoted this Wikipedia article. No one but a specially trained astronomer knows what a "tabulated zero points" is. Another part of what I removed was an external http reference, that was a dead link, leading to a page with nothing on it. If you have a reference to "tabulated zero points" and can explain what they are, in plain, non-technical, English, please do. I am really curious. Nick Beeson ( talk) 21:25, 24 February 2015 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Apparent magnitude. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{
Sourcecheck}}
).
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 5 June 2024).
Cheers.— InternetArchiveBot ( Report bug) 14:23, 16 October 2016 (UTC)
If true, could we note somewhere that 5 magnitudes fainter implies 10 times further away (since it is used in distance modulus) ? - Rod57 ( talk) 19:22, 16 January 2017 (UTC)
The cite seems to say limiting magnitude 31.2 - it would help to have a quote for the 31.5 in the footnote, a search of the paper for the number 31.5 turns up a blank. Is it a typo? Robert Walker ( talk) 10:01, 20 May 2018 (UTC)
There are many problems with this article page that need significant improvements or update. Fixes include:
I have attempted an improvement in the Introduction, but from the fragmentary nature of the article's text is near impossible to repair.
History section
The History section is very confusing and is poorly cited. Various contradictions appear with Magnitude (astronomy)#History
Absolute magnitude section
Most of this should be simplified, summarised and condensed. It should plainly mention that apparent magnitude is independent of distance, while absolute magnitude is based on an arbitrarily set distance of 10 parsec.
Table of examples
Most of this listing is theoretical and difficult to understand. Suggest making a shorter Table with atypical values for bright star and planets. he labels should b changed from "planet Mercury" to Mercury (planet) which would make this more readable. (or even a separate column?)
NOTE: @ Lithopsian: There also needs to be an explanation of usage. Many articles have odd usage, like "magnitude 6.0" or or a " the components are magnitudes 4.0 and 5.1 respectively" [3] If magnitude is the unit measure of brightness, then the value must be followed by the unit measure. e.g, "6th magnitude' or "6.0v magnitude" or a "double star is 4.5v and 5.6v magnitude" must be correct. Using the plural of magnitude is also incorrect usage in this respect. Better usage would be "magnitude of 6.0" I find few examples of the reverse usage in the popular or astronomical literature. The claim "correct usage of magnitude as a unit," must be problematic? RfC??
Arianewiki1 ( talk) 08:27, 19 May 2019 (UTC)
The one thing that the Standard reference values section doesn't seem to discuss is standard reference values, although there is a table of standard fluxes in various passbands. The text of the section is just general chit-chat, very poorly-referenced. I can't think of a name for it. Should it just be dumped and written from scratch? Chopped up and farmed out to other places like the history section? Lithopsian ( talk) 19:26, 7 June 2019 (UTC)
The article mentions that magnitude determination was crude and subjective before the invention of photodetectors, but I do wonder if there would be a way of classifying things in a repeatable fashion to a certain arbitrary level of precision - say, 0.1 on a log2 scale? (Which would give us less than 100 steps from "too faint to see" up to "brightest known object other than the sun and moon", and it's entirely possible to rank printed or on-screen greyscales more finely than that, by eye, so long as you can compare between them, and the dynamic brightness of a VDU or piece of paper is far less than that of natural light)
There are various methods I could think of... for example, the earliest hour that a star becomes visible after sunset, especially if you make repeat measurements at the summer and/or winter solstice and equinoxes, using some way of excluding visual pollution from the horizon or nearby dwellings (e.g. the classic lensless paper tube "telescope", or the makeshift observatory of a building missing its roof - the latter of which, along with a parabolic support made of bricks, was something actually used by pre-optical-glass astronomers, especially in Arabia). Date and time was something much more easily measured even in antiquity, and the motion of the stars and planets themselves was used to measure such. Your determination could then be checked by seeing whether certain well known benchmark stars were or were not yet visible, and a ranked list drawn up and refined over time. Once you had sufficient entries, it would be enough to simply wait for the first moment the star / planet of interest became visible, and quickly check to see which other stars off the list in the general predicted neighbourhood were already visible, in order to add the as-yet unranked one into the catalogue in the right place...
Maybe it wouldn't be absolutely accurate, or mathematically precise other than in terms of direct comparison, but for the type of astronomy that was even possible (and thought relating to it) in the pre-telescopic age, it would likely have been more than sufficient, and still fairly scientifically valid. Astronomers of old weren't entirely stupid, after all, just limited in the equipment they had available. It's not beyond the realm of imagination to consider they might have come up with some clever scheme to repeatably determine the objective brightness of a star (after all, I just pulled one out of my ass, and I haven't had a lifetime of pondering on the meaning of the universe in an age long before multichannel TV and the internet); the brightening and darkening of the sky, on clear nights, in an age before any meaningful atmospheric or indeed much light pollution, would have been like the apocryphal clockwork, and something you could set your biological photometer by. 146.199.60.87 ( talk) 19:41, 11 August 2019 (UTC)
@ Lithopsian: Your last edit was a valiant attempt, but now you have "The magnitude scale is logarithmic..." while the next sentence begins "The magnitude scale is reverse logarithmic...". Your comment "not entirely convinced it is better" is well said :) Definitely a tough topic to introduce without confusing people. Might've been better to just revert the unregistered user's edit; what was there before was much clearer, in my opinion. Assambrew ( talk) 08:19, 16 October 2020 (UTC)
Just noticed that "apparent brightness," though redirecting here, isn't talked about at all, although the article seems to use it to mean something specific. Perhaps it could be brought up (or removed)? – LogStar100 ( talk) 19:24, 3 February 2021 (UTC)
The table "Standard apparent magnitudes and fluxes for typical bands" lists various bands. Jy column at first appears to follow the spectral black body curve, as would be expected, since the units are per Hz, and agnostic of the band width, however the Jy values for bands g,r,i,z are inconsistent with the above bands and appear to be in error.
This seems to me a little bit academic, because when Mercury is at superior conjunction, you can't see it. The same thing goes for the minimum brightness of Mercury (around inferior conjunction). Realistically, the most useful apparent magnitude of Mercury is going to be that around maximum elongation, right? Double sharp ( talk) 09:13, 2 October 2021 (UTC)
The table listing "Number of stars (other than the Sun) brighter than apparent magnitude in the night sky" seems not correct. If the number 9100 is correct, the numbers at the top should also include the magnitude on the respective rows and the stars on rows above, as the number 9100 from Bright Star Catalogue implies. That is, the second row in that column should say 5 rather than 4. (Maybe other lines should also be changed.) Fomalhaut76 ( talk) 15:25, 20 March 2023 (UTC)
It is stated that the magnitude scale can be related to the decibel scale, as one magnitude step equals exactly 4 dB. I can see that this is mathematically correct, but is there anyone actually using decibel in this way? If no source to actual use of decibel related to apparent magnitude, then the statement should be deleted, as it does not convey any useful information. JakobT ( talk) 08:13, 9 August 2023 (UTC)
It would be great if someone could add into the list the apparent magnitudes of Jupiter when seen from certain moons, a "full Jupiter" e.g. from Metis, the Galilean moons or Himalia. 2001:4BC9:1F98:112C:B897:9213:2412:1F13 ( talk) 17:07, 8 October 2023 (UTC)
Hi! Both this page and Magnitude (astronomy) claim that Pogson defined magnitude zero to be based on Polaris = 2.0, and then astronomers switched to Vega = magnitude 0.0. I was curious about the history of magnitude, and fell down a rabbit hole of research, and then an wrote an article called The Cursed History of Star Brightness [5] about my findings: I tracked down Pogson's original paper, and it actually defined magnitude 6.0. In fact, this page's history of magnitude section contains some errors in the large citation-free paragraphs.
Magnitude (astronomy) makes the same claim that astronomers defined magnitudes using Vega = 0.0, but cites page 182 of a book. That book, as seen on https://books.google.com/books?id=Ps_6zjUCR3wC&q=182#v=snippet&q=182&f=false here, does mention Vega's variability several pages after page 182, but it describes a model for the spectrum of Vega from 1991, far after Johnson's system was invented, and doesn't say that the model is used to calibrate magnitude zero.
This page also claimed that "Therefore, the magnitude scale was extrapolated to all wavelengths on the basis of the black-body radiation curve for an ideal stellar surface at 11000 K uncontaminated by circumstellar radiation". It cites https://archive.today/20121204144725/http://www.astro.utoronto.ca/~patton/astro/mags.html, but that website doesn't mention anything about a black body spectrum. I've removed it in my edit, but if anyone does have a source for that claim I'd love to see it.
Since I found many primary sources while doing research for my article, I've edited this page to reflect what I understand is the correct history. If any of you Wikipedia editors have any comments, suggestions on how to rewrite it, or sources about the history of magnitude, please let me know! Explanaria ( talk) 20:28, 23 May 2024 (UTC)