Questions tagged [apparent-magnitude]
Questions regarding how bright an object appears to be.
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Adhara ultraviolet magnitude
I see Adhara is cited in many places (for example, here) as being the brightest source of ultraviolet light in the sky. The particular source uses the modifier "extreme", but most other ...
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Which value of the apparent magnitude do I use from a Supernova light curve
I am trying to get the distance modulus from a light curve of a supernova and obviously the apparent magnitude changes with time. Not only that but there are so many filters with different mags.
So my ...
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Star cluster absolute magnitude and color index
I'm given a question where I need to calculate the absolute magnitude (Mv) and color index (B-V) of a star cluster consisting of 40 Vega type stars and 4000 stars, which have an Mv of +5 and B-V of 1.
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calculate the absolute and apparent magnitude for a binary star system
I'm used to use this formula to find the apparent magnitude of a star
$$m_1 - m_2 = -2.5 log(\frac{f_1}{f_2})$$
If both star are at the same distance from us and their luminosity is the same, does it ...
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What stars are brighter then any star nearer to the south celestial pole [closed]
What stars are brighter (apparent magnitude) then any star nearer to the south celestial pole?
I know that there’s no bright star within a few degrees of the south celestial pole.
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A what distance could we see the Sun?
How far away can we see the Sun with the naked eye?
How far with an amateur telescope? And with the James Webb telescope?
In my own calculations the Sun would appear magnitude 6 at 56 ly, magnitude 8 (...
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Surface Brightness Definition
I know the surface brightness is calculated by taking the apparent magnitude of an object and then divide by the size of the thing. But this is more of "observed" surface brightness, how do ...
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Is Uranus the farthest object in Solar System that you can see with naked eyes?
The following text is from this article:
The fact is, even at its brightest, Uranus is still quite faint. It’s barely perceptible as a dim speck of light to the unaided eye, even under dark skies. At ...
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How bright will Alpha Centauri A be from Earth when it becomes a red giant?
As of right now, both stars from Alpha Centauri are in their main sequence stages, but eventually Alpha Centauri A is going to quickly expand in a matter of time, and I’m pretty sure its luminosity is ...
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How bright does Venus appear from the moon if it replaced Earth?
If you were standing on the moon, Earth will appear mostly around -17.7 at maximum brightness. However, since Venus has a higher albedo than Earth, Venus would be brighter. What would be Venus's ...
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What is the brightness and size of Jupiter from the Galilean moons, the closest moon, and the farthest moon?
From the Moon, Earth would appear 4 times larger than the Moon seen from Earth, and the magnitude of a "full earth" is around -17.
However, Jupiter from the Galilean moons appear much larger ...
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Are apparent magnitudes corrected for extinction at zenith?
For example, according to Google, the apparent magnitude of the sun is $-26.74^m$.
Is this the apparent magnitude viewed through Earth's atmosphere when the object is at zenith?
(Assuming most ...
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absolute magnitude of an asteroid
I've done some research and found that one could derive the absolute magnitude $H$ of an asteroid in the following way. $H$ is the brightness of the asteroid, observed on Earth, if the asteroid were ...
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How to calculate absolute magnitude of planets?
Knowing:
Star's radius $r_s$ , luminosity $L_s$, and absolute magnitude $V$
Planet's radius $r_p$ , albedo $a$ , and distance $d_s$
How can you calculate the absolute magnitude of a planet in a ...
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How do stellar magnitude and integrated magnitudes compare, perceptually?
(P.S. this is naked eyed)
Magnitudes are easily defined for point-like objects i.e. stars. However, for extended objects, the "magnitudes" quoted are actually integrated magnitudes.
For ...
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Calculating absolute error in apparent magnitude of a star [duplicate]
I know that the apparent magnitude $m$ of a star is related to its intensity by Pogson's law:
$m = −2.5 log_{10} I$.
And I also know that the absolute error is defined as follows:
Let $\hat{𝑥}$ be an ...
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Computation of magnitude of the secondary
How to approximately compute the magnitude of the secondary in a binary when I know the magnitude of the primary, masses, radii, and approximate luminosities for both of them, please? Thank you very ...
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V magnitude of binary components
Which catalog provides visible magnitudes of binary components, please? How to find it, for instance, in VizieR, please? I have a list of binaries.
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What would be the highest possible naked-eye apparent magnitude?
What would be the highest possible magnitude $m$ of some star that could be viewed with a naked-eye? I am acquainted with this question, but mine is about the ideal conditions.
In order to achieve ...
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What is the smallest (brightest) magnitude that the JWST can safely observe?
Similar to Can JWST be damaged by looking at a bright star?. I'd like to know the brightest magnitude that the James Webb Space Telescope can safely observe without damaging any of its instruments.
...
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Can JWST be damaged by looking at a bright star?
Can JWST be damaged by looking at a bright star?
The Sun as well as particularily bright solar-system objects like Jupiter, Venus or the Moon not meant with this question.
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What is the apparent magnitude of the Milky Way from the viewpoint of the Large Magellanic Cloud?
Wikipedia contains the essentially unsourced claim that
From a viewpoint in the LMC, the Milky Way's total apparent magnitude would be −2.0—over 14 times brighter than the LMC appears to us on Earth—...
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Brown Dwarf Sun: How dim can a star be in the visible spectrum and still provide enough heat for a planet to be habitable?
After reading this question on wordbuilding. I saw that a brown dwarf emits most of its energy in the infrared which made me wonder: How bright would such a star appear from it's exoplanet in the ...
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Finding stellar radii
Is apparent magnitude of star, distance(in pc) and effective temperature enough to calculate its stellar radii or we need some extra information?
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How to compute a Flux through a filter using SYNPHOT in Python
I am in the process of building an exposure time calculator to help nail down the exposure times I need for different targets in my observatory.
In amateur astronomy imaging, we use a filter called ...
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What is going on with comet C/2021 A1 Leonard? Is it going to be bright this weekend or not?
I have to plan an excursion to try to find clear evening skies to try to see if we can spot comet C/2021 A1 Leonard about 10 to 15° above the ocean in the Southwest after sunset this weekend.
I'm ...
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What is Jupiter's apparent magnitude as watched from Uranus?
Saturn's apparent magnitude from Uranus is +3.228. Jupiter orbits closer to the sun than Saturn. Can we therefore expect Jupiter’s apparent magnitude from Uranus to be dimmer than Saturn's, or is it ...
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How to find magnitude of one galaxy being a hypothetical observer in the other?
The given apparent magnitude of M31 galaxy is 3.4$^m$, M33 - 5.7$^m$. I wonder how can I calculate the apparent magnitude of one of them (ex. M33) if I imagine myself being in the other (ex. M31)?
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What is Saturn’s apparent magnitude at its brightest when viewed from Uranus?
Considering that the apparent magnitude scale is an inverted scale; what is the lowest apparent magnitude of Saturn that can be seen from Uranus. We are of course talking about when Saturn is viewed ...
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What is 5 in 5log10 the value of?
I know what 2.5 stand for in $2.5 \log_{10}$, but what does the number 5 in $5\log_{10}$ stand for and what application does it have.
Thus, why is the number a five and not a four, or a three, or ...
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Is subtracting one apparent magnitude from another ever practical?
Does a circumstance exist for subtracting one apparent magnitude from another to reach a solution to a problem? Is it ever suitable to do so?
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Why does apparent magnitudes get increased fourfold when distances get halved, instead of simply getting doubled?
This website explains:
The apparent brightness of a star is proportional to 1 divided by its distance squared. That is, if you took a star and moved it twice as far away, it would appear 1/4 as ...
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Could Neptune be viewed with the naked eye from Uranus?
Which star or planet in our night sky can match what Neptune would look like when viewed from Uranus, or one of its moons?
The answer would be for the most favourable condition, which is when Neptune ...
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E(B-V) , the color excess between B and V bands, for galaxy at redshift 0
Following Mo et al. 2010 (page 479), the quantity $E(B-V)$, called the color excess between B and V bands, is equal to:
$$E(B-V) = A_B - A_V = (B - V) - (B - V)_0 = (m_B - m_V) - (M_B- M_V)$$
where $...
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Brightest Stars (by its Apparent Magnitude) List beyond 300
I've been observing the stars and I have found some lists on internet that sort them by its apparent magnitude (m), so you end up with lists of brightest-stars like this one: https://www.star-facts....
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Estimate the shape of an object based on flux curve
Is there an aproximation to know the shape of a dust cloud,etc based on the magnitude/flux curves of stars they transit? Example, can I know if the shape is (at least in 2 dimensions) elliptical, ...
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Apparent Magnitude of First quarter Moon [closed]
Given
Apparent magnitude of moon is -12.5.
Distance of moon and earth is 384400 km.
Diameter of Moon is 31 arcmin.
Phase of moon is 0.5.
Find the apparent magnitude of first quarter moon.
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Why must all magnitude systems have a reference point?
Let $f_*$ and $f_0$ be the observed flux of a star and a reference flux in a particular spectral band, and let $m_*$ and $m_0$ be their respective apparent magnitudes. Then the star's magnitude is ...
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Has lunar opposition surge ever been observed from Earth? From Earth orbit?
This thorough answer to How long does lunar opposition surge last? Are there measurements of the full Moon getting suddenly brighter? details observations of lunar opposition surge by the Clementine ...
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When calculating absolute magnitudes of distant objects, do you use the light-travel distance or the comoving distance?
I want to calculate the absolute magnitude of GN-z11. Its light-travel distance is 13.4 billion ly (4.1 Gpc), its comoving distance is 32 billion ly (9.8 Gpc), and its apparent magnitude is $25.8$. ...
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How long does lunar opposition surge last? Are there measurements of the full Moon getting suddenly brighter?
Wikipedia's opposition surge is a short article and forwards shadow hiding and coherent backscattering as proposed mechanisms, but it doesn't really explain how much the brightness of the Moon ...
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Limiting magnitudes for different telescopes
I live in an extremely light polluted place. On a new moon night, magnitude 3.5 stars are at the limit of naked eye visiblity on clear nights, and the Orion nebula is visible as a smudge through my ...
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How to compute for Distance Modulus' uncertainty/ies?
This is rather a short question. As we know of;
Distance Modulus (DM) $\mu = 5 \log d - 5$
If $d = 168_{-14.9}^{+27.5}$ pc ($3\sigma$ value), how can I possibly compute for $\mu$'s uncertainty?
P.S. ...
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If Planet Nine indeed exists, how large a impact event there should be to be seen from Earth?
Recently I've found this news article, A meteorite crashed into the Moon during total lunar eclipse in January, about a collision into the moon that happened while a lunar eclipse was under way. ...
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How was Mars' very noticeable change in apparent magnitude explained by the Geocentric Model?
In the geocentric model, the Sun, the Moon, and the 5 naked-eye planets (Mercury, Venus, Mars, Jupiter, Saturn) all orbited Earth.
Today we know that the planets orbit the Sun, and thus they come ...
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How much dimmer is a partial solar eclipse that goes from -26.71 to -25.89?
Based on what I found in Stellarium, for Vlissingen, Netherlands, on July 2, 1666 there was a partial eclipse with a change of apparent brightness -26.71 to -25.89.
Is it valid to say based on the ...
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How to convert between AB and Vega magnitudes?
This might be a bit silly, but I'm really struggling with a conversion.
I have apparent AB magnitudes: $$m_{AB} = -2.5 \log_{10}(f_\nu [\mu Jy]) + 25$$ that I would like to convert to Vega magnitudes, ...
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Formula to calculate the apparent magnitude of Earth from arbitrary distances
I would like to calculate the apparent magnitude of Earth from various distances, say from the Voyager probe at this moment or from various stars in the sky. I know there must be a formula that I can ...
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How many photons does it take to determine the existence of a distant object?
This applies to any object, but I see the recent discovery of the oldest, most distant galaxy and it started me wondering what the limits are. Presumably you can do better with a bigger telescope and ...
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Approximate spectral type and luminosity given apparent magnitude and distance
I am looking at the data acquired from the Gaia DR2 survey. I found that most of the stars had their distance and apparent magnitude catalogued, but not their spectral type and luminosity class. Is ...
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