Formulas! We should include formulas here and in absolute magnitude.-- AN
The 1st paragraph for this page gets confusing rather quickly. Would it be possible for someone with knowledge of the subject to clarify the definition before jumping into numerical examples?
When amateurs refer to magnitude in astronomy, they probably don't know the difference between apparent magnitude and absolute magnitude. This also creates a problem for the disambigation link repair: I, for example, have no idea whether to pipe magnitude link from (exampple) All Sky Automated Survey article to absolute or apparent. Could sb create the article in the heading explaining the basic magnitude idea in astronomy and comparing the specific types, so the current two articles would become subarticles? Note that currently it is a redirect to magnitude disambig - far from a pefect solution.-- Piotr Konieczny aka Prokonsul Piotrus Talk 17:47, 9 January 2006 (UTC)
Maybe I missed it, but I cannot find the modern reference point from which all other magnitudes are determined. I see that Vega used to be defined as zero, but not what the new standard is.
- me neither. Article doesn't explain either the Zero or any reason for the step size. I assume there is one?
I miss information on how the apparent magnitude of dim objects (galaxies, nebulae) is calculated, and how that is related to their visibility. Is the Triangulum Galaxy equally visible on the night sky as a star with the same magnitude? Apus 09:00, 25 October 2006 (UTC)
I see, that some information were lost during editions (for example interwiki). Someone should check the history carefully. 83.14.10.10 15:31, 31 October 2006 (UTC)
In Talk:Andromeda_Galaxy#Apparent_magnitude the suggestion has been made "In general, it is much easier to find B magnitudes than it is to find V magnitudes, so B magnitudes are generally used in the infoboxes. However, the infoboxes are set up with "(V)" hardwired into them. It might be better just to set up the infoboxes so that the wave band may be specified in the inserted text rather than in the template".
However, this article says "The V band was chosen for spectral purposes and gives magnitudes closely corresponding to those seen by the light-adapted human eye, and when an apparent magnitude is given without any further qualification, it is usually the V magnitude that is meant, more or less the same as visual magnitude". Is there a good resolution for this? I have also posted on Template:Infobox Galaxy. Thincat 10:19, 6 June 2007 (UTC)
We know that the V band is usually given to represent the visual magnitude. However the other bands should have a slight effect on this, particularly the B and R bands. Is there a way to quantify this? For example during a deep lunar eclipse the moon has a pronounced red color and simply assigning the V (green) magnitude would underestimate how bright the moon appears to the naked eye. — Preceding unsigned comment added by 137.75.201.73 ( talk) 21:55, 12 October 2015 (UTC)
Nearly one year ago, on October 29, 2006, the table titled Scale of Apparent Magnitude was deleted because the URL of the source could not be found. As of September 15, 2007, the table has been reinserted into the article, this time with a URL to Jim Kaler's THE 151 BRIGHTEST STARS. The fourth paragraph of Kaler's article provides at least some of the information and data shown in the table. I will personally search for additional sources (URLs) dealing with this exact subject and insert them onto the table. However, I perfectly welcome the contributions of other Wikipedia editers to the Scale of Apparent Magnitude data table, because I feel that this table would prove very beneficial to anyone curious about the various orders of magnitude and how they are distinguished from each other. -- Richontaban 16:19, 15 September 2007 (UTC)
In some calculations on this page the value '2.5' is used. Other calculations use '2.512'. Shouldn't they at least be consistent? Dfmclean 18:17, 11 October 2007 (UTC)
The correct value is the (5th root of 100) = 2.511886432. But yes, humans like to round off for simplicity. 2.5^5 is only 97.65625. -- Kheider 20:57, 11 October 2007 (UTC)
-Actually, In Pogson's equation, 2.5 is 2.50000, an exact number from 5/2, not a round off of the number 2.512. The value 2.512 is found for the ratio of brightness between adjacent integer magnitudes. (i.e. It is the fifth root of 100). The 2.5 from Pogson's equation is thus completely different from 2.511886432...
Officially, yes, it is actually exactly 2.5. It is no longer the 5th root of 100, but was adjusted for ease of computation. Having irrational numbers in there just gets to be a pain... So 5 magnitudes is no longer exactly 100 times brighter (or dimmer). AstroDave ( talk) 02:41, 19 November 2008 (UTC)
Apparently, there is no universal agreement. According to Sky and Telescope magazine ( [1]): "One magnitude thus corresponds to a brightness difference of exactly the fifth root of 100, or very close to 2.512 — a value known as the Pogson ratio." --- Glenn L ( talk) 04:26, 30 October 2009 (UTC)
Hypothetically speaking, if the Sun was to suddenly wink out at this instant in time, the total isotropic radiation flux falling on the Earth's surface from the surrounding cosmic night sky would amount to -6.5 magnitudes. This quantity was first determined by Abdul Ahad (b. 1968-) and is generally known as Ahad's Constant [2]. 90.193.170.221 ( talk) 14:35, 8 March 2008 (UTC)
The Table has an entry : "−3.7 Minimum brightness of Venus". Since Venus can transit the Sun, I would expect the minimum brightness to be substantially positive. It will then only be lit by the Earth and Moon and about half of the stars. -- 82.163.24.100
To be rigorous and future-proof, the magnitudes given should be qualified by a mention of the observer's position. To Messenger, Sol must be nearer Mag 29. 82.163.24.100 ( talk) 21:11, 9 October 2008 (UTC)
Venus is at its dimmest when it's transiting the Sun. But its brightness at that time is completely unmeasurable. So its minimum brightness would have to be calculated as the limit of measured brightnesses as it approaches the Sun. But what would that achieve? The minimum brightness of Venus is something that can never be observed. I suggest that this line is removed. Occultations ( talk) 15:35, 28 February 2009 (UTC)
Is this table really necessary? It appears just to show the reader how to round to the nearest integer. Even assuming that the reader doesn't know how to do this, none of the magnitudes reported in the article are actually reported rounded to the nearest integer, which would seem to make the table irrelevant to the article. Is there some reason for the inclusion of this that I am missing? — Jeremy ( talk) 22:59, 25 November 2008 (UTC)
I removed Ahad's constant from the table, since:
The reference, which was given to justify Ahad's constant, links to a commercial web site also promoting and selling the works of fiction by Ahad. -- Crowsnest ( talk) 01:11, 23 February 2009 (UTC)
It is very rare for scientific phonomna to be named after a
SF author. The only case I can think of is Clarke orbit, which is rarely refered to as such, and normally refered to as geo-stationary (or similar). It seems to me that much of Ahad's constant (and other values) are self promotion, rather than notable science, and should not be included. I would guess that his concepts have previously been covered by authors, but not self promotoed in this way.
On a second note, Ahad's constant is an average value of light in the middle of interstellar space, all the other values are for objects as seen from the Earth, and as such Ahad's constant does not fit in with the list.
Martin451 (
talk) 14:08, 23 February 2009 (UTC)
This seems like a pretty obvious not-include unless it's a much more common term than the current choice of sources would suggest. -- BenRG ( talk) 15:35, 23 February 2009 (UTC)
In the calculation for how much fainter Pluto is than naked-eye visibility, the value 6.0 is used, as in 2.512(13.65 - 6.0) = 1148. The actual value for the "faintest stars observable with naked eye under perfect conditions" is given earlier as 6.5, which would make Pluto 2.512(13.65 - 6.5) = 725 times fainter. So, is it 6.0 or 6.5? Zaardvark ( talk) 16:18, 30 June 2009 (UTC)
Here for the normal experience limiting magnitudes during various conditions. Practically available best conditions allow a normal vision normal experience viewer about 5.75 to 6.0, which fits better with my personal experience. ... said: Rursus ( mbork³) 21:41, 16 November 2009 (UTC)
I was bold. I reverted limiting mag to 6.0, but then added a "trained naked eye amateur astronomer" at 7.0. ... said: Rursus ( mbork³) 08:20, 17 November 2009 (UTC)
I'm new here, but I'd like to suggest that a 6.0 is visible even at less than average dark sites, and is an indication of either eye defects or less than average conditions at a true dark site. As an astronomer, in my experience, observations in the high 7s require a lot of experience and perfect eyesight. However high 6 and low 7 observations at good sites do not require much beyond the cooperation of weather. M81, a galaxy of reported magnitude 6.9(and thus more difficult than the equivalent stellar magnitude), has been seen by people with the unaided eye, and while not easy, is not considered a gargantuan feat. A limiting magnitude of 6 suggests defective eyesight or light polluted skies. Unfortunatey the experience of most people is of spoiled, light polluted skies. If the intent of the list was to convey a liting magnitude of 6.0 for 'mean'people under moderately light polluted skies, then it would be justified. As I read it, however, I got the impression that beyond 6.0 is unfeasable for people except if they have superhuman eyesight and live on a mountain, and that's simply not true. —Preceding unsigned comment added by 80.235.35.162 ( talk) 15:37, 27 November 2009 (UTC)
The wiki article lists M81 at mag 7.89 and other sites list at as 6.9 as you mention. Do you have any idea why the difference? Is the extragalactic database listing the visual magnitude? -- Kheider ( talk) 21:52, 27 November 2009 (UTC)
How can both of Hydra and Nix be Pluto's smallest moon (as in the list)? -- 87.93.30.46 ( talk) 23:21, 6 June 2010 (UTC)
Unless this can be sourced, it's original research. - Mike Rosoft ( talk) 11:13, 8 June 2010 (UTC)
Throughout the article -12.6 was the value used for the brightness of the full moon. But the table gives -12.92, which changes the difference with the Sun from 400,000 time brighter to 340,000 times. I used the latter number throughout but I do not know which is correct. Please if you know which is correct edit the article to reflect that. -- Nick Beeson ( talk) 19:19, 2 July 2010 (UTC)
There is -2.50 as 'Minimum brightness of Moon when near the sun (New Moon)' in the table. But Sirius' brightness is about -1.5 so new Moon should be 2.5 times brighter than Sirius.
WTF? Isn't this the apparent visual magnitude? And visual means what I see with my eyes. And I certainly can't see new Moon, but I do see Sirius. Something is wrong there or I just don't get it.
85.217.34.189 (
talk) 01:28, 9 March 2011 (UTC)
And, Sun is about 400 000 times brighter than mean Full Moon, but mean Full Moon only about 12 500 times brighter than minimum New Moon? This may be original research, but it cannot be so. And, as pointed above, there is no source for the -2.5 figure, so that is as much original research until cited. 82.141.127.5 ( talk) 18:38, 14 May 2011 (UTC)
From my research and calculations the full moon (at perigee) is -12.86 magnitude due to being about 6% closer, compared with the magnitude at mean distance of -12.74. Also with perihelion added the sun is about 1.6% closer. The total brightness then increases to -12.90. For the new moon, it can be calculated that the magnitude is -2.5 with no crescent showing, just the Earth shine. — Preceding unsigned comment added by 174.16.248.236 ( talk) 20:06, 8 September 2015 (UTC)
Maximum brightness of Jupiter -2.95 2485-Oct-16 http://ssd.jpl.nasa.gov/horizons.cgi#results —Preceding unsigned comment added by Hevron1998 ( talk • contribs) 13:06, 26 September 2010 (UTC)
This is a frivolous entry for several reasons: firstly, there is no standard "naked eye"; secondly the source is a first person account in an email on a newsgroup; and thirdly the actual quote from the source is "On occasion I also seemed to pick up another star, HD 85828" - it's rather fanciful to interpret this as "the faintest star known to be observed with the naked eye".
Any suggestions on how this could be improved? I suggest this text (first couple of pages) as a relevant source. There appears to be a significant difference between the limits of visibility in the open sky (around 6.5 to 7) and the limits of visibility when some apparatus or aperture is used to restrict the vision to a small region of sky (up to 8.1 to 8.5). — Preceding unsigned comment added by Bobathon71 ( talk • contribs) 18:00, 10 July 2011 (UTC)
Formulas! We should include formulas here and in absolute magnitude.-- AN
The 1st paragraph for this page gets confusing rather quickly. Would it be possible for someone with knowledge of the subject to clarify the definition before jumping into numerical examples?
When amateurs refer to magnitude in astronomy, they probably don't know the difference between apparent magnitude and absolute magnitude. This also creates a problem for the disambigation link repair: I, for example, have no idea whether to pipe magnitude link from (exampple) All Sky Automated Survey article to absolute or apparent. Could sb create the article in the heading explaining the basic magnitude idea in astronomy and comparing the specific types, so the current two articles would become subarticles? Note that currently it is a redirect to magnitude disambig - far from a pefect solution.-- Piotr Konieczny aka Prokonsul Piotrus Talk 17:47, 9 January 2006 (UTC)
Maybe I missed it, but I cannot find the modern reference point from which all other magnitudes are determined. I see that Vega used to be defined as zero, but not what the new standard is.
- me neither. Article doesn't explain either the Zero or any reason for the step size. I assume there is one?
I miss information on how the apparent magnitude of dim objects (galaxies, nebulae) is calculated, and how that is related to their visibility. Is the Triangulum Galaxy equally visible on the night sky as a star with the same magnitude? Apus 09:00, 25 October 2006 (UTC)
I see, that some information were lost during editions (for example interwiki). Someone should check the history carefully. 83.14.10.10 15:31, 31 October 2006 (UTC)
In Talk:Andromeda_Galaxy#Apparent_magnitude the suggestion has been made "In general, it is much easier to find B magnitudes than it is to find V magnitudes, so B magnitudes are generally used in the infoboxes. However, the infoboxes are set up with "(V)" hardwired into them. It might be better just to set up the infoboxes so that the wave band may be specified in the inserted text rather than in the template".
However, this article says "The V band was chosen for spectral purposes and gives magnitudes closely corresponding to those seen by the light-adapted human eye, and when an apparent magnitude is given without any further qualification, it is usually the V magnitude that is meant, more or less the same as visual magnitude". Is there a good resolution for this? I have also posted on Template:Infobox Galaxy. Thincat 10:19, 6 June 2007 (UTC)
We know that the V band is usually given to represent the visual magnitude. However the other bands should have a slight effect on this, particularly the B and R bands. Is there a way to quantify this? For example during a deep lunar eclipse the moon has a pronounced red color and simply assigning the V (green) magnitude would underestimate how bright the moon appears to the naked eye. — Preceding unsigned comment added by 137.75.201.73 ( talk) 21:55, 12 October 2015 (UTC)
Nearly one year ago, on October 29, 2006, the table titled Scale of Apparent Magnitude was deleted because the URL of the source could not be found. As of September 15, 2007, the table has been reinserted into the article, this time with a URL to Jim Kaler's THE 151 BRIGHTEST STARS. The fourth paragraph of Kaler's article provides at least some of the information and data shown in the table. I will personally search for additional sources (URLs) dealing with this exact subject and insert them onto the table. However, I perfectly welcome the contributions of other Wikipedia editers to the Scale of Apparent Magnitude data table, because I feel that this table would prove very beneficial to anyone curious about the various orders of magnitude and how they are distinguished from each other. -- Richontaban 16:19, 15 September 2007 (UTC)
In some calculations on this page the value '2.5' is used. Other calculations use '2.512'. Shouldn't they at least be consistent? Dfmclean 18:17, 11 October 2007 (UTC)
The correct value is the (5th root of 100) = 2.511886432. But yes, humans like to round off for simplicity. 2.5^5 is only 97.65625. -- Kheider 20:57, 11 October 2007 (UTC)
-Actually, In Pogson's equation, 2.5 is 2.50000, an exact number from 5/2, not a round off of the number 2.512. The value 2.512 is found for the ratio of brightness between adjacent integer magnitudes. (i.e. It is the fifth root of 100). The 2.5 from Pogson's equation is thus completely different from 2.511886432...
Officially, yes, it is actually exactly 2.5. It is no longer the 5th root of 100, but was adjusted for ease of computation. Having irrational numbers in there just gets to be a pain... So 5 magnitudes is no longer exactly 100 times brighter (or dimmer). AstroDave ( talk) 02:41, 19 November 2008 (UTC)
Apparently, there is no universal agreement. According to Sky and Telescope magazine ( [1]): "One magnitude thus corresponds to a brightness difference of exactly the fifth root of 100, or very close to 2.512 — a value known as the Pogson ratio." --- Glenn L ( talk) 04:26, 30 October 2009 (UTC)
Hypothetically speaking, if the Sun was to suddenly wink out at this instant in time, the total isotropic radiation flux falling on the Earth's surface from the surrounding cosmic night sky would amount to -6.5 magnitudes. This quantity was first determined by Abdul Ahad (b. 1968-) and is generally known as Ahad's Constant [2]. 90.193.170.221 ( talk) 14:35, 8 March 2008 (UTC)
The Table has an entry : "−3.7 Minimum brightness of Venus". Since Venus can transit the Sun, I would expect the minimum brightness to be substantially positive. It will then only be lit by the Earth and Moon and about half of the stars. -- 82.163.24.100
To be rigorous and future-proof, the magnitudes given should be qualified by a mention of the observer's position. To Messenger, Sol must be nearer Mag 29. 82.163.24.100 ( talk) 21:11, 9 October 2008 (UTC)
Venus is at its dimmest when it's transiting the Sun. But its brightness at that time is completely unmeasurable. So its minimum brightness would have to be calculated as the limit of measured brightnesses as it approaches the Sun. But what would that achieve? The minimum brightness of Venus is something that can never be observed. I suggest that this line is removed. Occultations ( talk) 15:35, 28 February 2009 (UTC)
Is this table really necessary? It appears just to show the reader how to round to the nearest integer. Even assuming that the reader doesn't know how to do this, none of the magnitudes reported in the article are actually reported rounded to the nearest integer, which would seem to make the table irrelevant to the article. Is there some reason for the inclusion of this that I am missing? — Jeremy ( talk) 22:59, 25 November 2008 (UTC)
I removed Ahad's constant from the table, since:
The reference, which was given to justify Ahad's constant, links to a commercial web site also promoting and selling the works of fiction by Ahad. -- Crowsnest ( talk) 01:11, 23 February 2009 (UTC)
It is very rare for scientific phonomna to be named after a
SF author. The only case I can think of is Clarke orbit, which is rarely refered to as such, and normally refered to as geo-stationary (or similar). It seems to me that much of Ahad's constant (and other values) are self promotion, rather than notable science, and should not be included. I would guess that his concepts have previously been covered by authors, but not self promotoed in this way.
On a second note, Ahad's constant is an average value of light in the middle of interstellar space, all the other values are for objects as seen from the Earth, and as such Ahad's constant does not fit in with the list.
Martin451 (
talk) 14:08, 23 February 2009 (UTC)
This seems like a pretty obvious not-include unless it's a much more common term than the current choice of sources would suggest. -- BenRG ( talk) 15:35, 23 February 2009 (UTC)
In the calculation for how much fainter Pluto is than naked-eye visibility, the value 6.0 is used, as in 2.512(13.65 - 6.0) = 1148. The actual value for the "faintest stars observable with naked eye under perfect conditions" is given earlier as 6.5, which would make Pluto 2.512(13.65 - 6.5) = 725 times fainter. So, is it 6.0 or 6.5? Zaardvark ( talk) 16:18, 30 June 2009 (UTC)
Here for the normal experience limiting magnitudes during various conditions. Practically available best conditions allow a normal vision normal experience viewer about 5.75 to 6.0, which fits better with my personal experience. ... said: Rursus ( mbork³) 21:41, 16 November 2009 (UTC)
I was bold. I reverted limiting mag to 6.0, but then added a "trained naked eye amateur astronomer" at 7.0. ... said: Rursus ( mbork³) 08:20, 17 November 2009 (UTC)
I'm new here, but I'd like to suggest that a 6.0 is visible even at less than average dark sites, and is an indication of either eye defects or less than average conditions at a true dark site. As an astronomer, in my experience, observations in the high 7s require a lot of experience and perfect eyesight. However high 6 and low 7 observations at good sites do not require much beyond the cooperation of weather. M81, a galaxy of reported magnitude 6.9(and thus more difficult than the equivalent stellar magnitude), has been seen by people with the unaided eye, and while not easy, is not considered a gargantuan feat. A limiting magnitude of 6 suggests defective eyesight or light polluted skies. Unfortunatey the experience of most people is of spoiled, light polluted skies. If the intent of the list was to convey a liting magnitude of 6.0 for 'mean'people under moderately light polluted skies, then it would be justified. As I read it, however, I got the impression that beyond 6.0 is unfeasable for people except if they have superhuman eyesight and live on a mountain, and that's simply not true. —Preceding unsigned comment added by 80.235.35.162 ( talk) 15:37, 27 November 2009 (UTC)
The wiki article lists M81 at mag 7.89 and other sites list at as 6.9 as you mention. Do you have any idea why the difference? Is the extragalactic database listing the visual magnitude? -- Kheider ( talk) 21:52, 27 November 2009 (UTC)
How can both of Hydra and Nix be Pluto's smallest moon (as in the list)? -- 87.93.30.46 ( talk) 23:21, 6 June 2010 (UTC)
Unless this can be sourced, it's original research. - Mike Rosoft ( talk) 11:13, 8 June 2010 (UTC)
Throughout the article -12.6 was the value used for the brightness of the full moon. But the table gives -12.92, which changes the difference with the Sun from 400,000 time brighter to 340,000 times. I used the latter number throughout but I do not know which is correct. Please if you know which is correct edit the article to reflect that. -- Nick Beeson ( talk) 19:19, 2 July 2010 (UTC)
There is -2.50 as 'Minimum brightness of Moon when near the sun (New Moon)' in the table. But Sirius' brightness is about -1.5 so new Moon should be 2.5 times brighter than Sirius.
WTF? Isn't this the apparent visual magnitude? And visual means what I see with my eyes. And I certainly can't see new Moon, but I do see Sirius. Something is wrong there or I just don't get it.
85.217.34.189 (
talk) 01:28, 9 March 2011 (UTC)
And, Sun is about 400 000 times brighter than mean Full Moon, but mean Full Moon only about 12 500 times brighter than minimum New Moon? This may be original research, but it cannot be so. And, as pointed above, there is no source for the -2.5 figure, so that is as much original research until cited. 82.141.127.5 ( talk) 18:38, 14 May 2011 (UTC)
From my research and calculations the full moon (at perigee) is -12.86 magnitude due to being about 6% closer, compared with the magnitude at mean distance of -12.74. Also with perihelion added the sun is about 1.6% closer. The total brightness then increases to -12.90. For the new moon, it can be calculated that the magnitude is -2.5 with no crescent showing, just the Earth shine. — Preceding unsigned comment added by 174.16.248.236 ( talk) 20:06, 8 September 2015 (UTC)
Maximum brightness of Jupiter -2.95 2485-Oct-16 http://ssd.jpl.nasa.gov/horizons.cgi#results —Preceding unsigned comment added by Hevron1998 ( talk • contribs) 13:06, 26 September 2010 (UTC)
This is a frivolous entry for several reasons: firstly, there is no standard "naked eye"; secondly the source is a first person account in an email on a newsgroup; and thirdly the actual quote from the source is "On occasion I also seemed to pick up another star, HD 85828" - it's rather fanciful to interpret this as "the faintest star known to be observed with the naked eye".
Any suggestions on how this could be improved? I suggest this text (first couple of pages) as a relevant source. There appears to be a significant difference between the limits of visibility in the open sky (around 6.5 to 7) and the limits of visibility when some apparatus or aperture is used to restrict the vision to a small region of sky (up to 8.1 to 8.5). — Preceding unsigned comment added by Bobathon71 ( talk • contribs) 18:00, 10 July 2011 (UTC)