Questions tagged [brightness]
The brightness tag has no usage guidance.
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Where can i get epoch j2010.0 values for stars? [closed]
I just want to know that where can i find the epoch j2010.0 values for stars, their ra and dec values. is there any resource? any pdf or software library that gives these values?
Thanks ^^
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How to calculate apparent brightness in relation to the sun
I know that we can determine the apparent brightness of an object in our solar system using the following formula:
$$B=\frac{A\cdot L_S\cdot R^2}{D^2\cdot d^2}$$
$B$ = Brightness of observed object in ...
0
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1answer
96 views
How can the author of this article conclude that earth-shine on the moon is 100 times brighter than moon-shine on earth? [duplicate]
I don't understand the reasoning of the author of this article, on page 26. How can he conclude that full earth-shine on the moon is 100 times brighter than full moon-shine on earth?
15
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1answer
928 views
Exoplanet dip in transit light curve when the planet passes behind the star
In the animation below, I don't understand why the brightness slightly decreases when the planet is behind the star.
Where does this effect come from?
3
votes
1answer
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Why is T-Tauri So Dim?
I'm looking at stellar objects and doing some math here and...
Now, I can't find these values directly listed, but from it's relative magnitude and distance, (10.27, 471ly,) I calculate T-Tauri to ...
7
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3answers
557 views
Can we visually perceive exoplanet transits with amateur telescopes?
Is it possible for an amateur astronomer to visually perceive an exoplanet transit by the change of brightness of the star via observations spaced over time, or is the variation of the brightness too ...
2
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0answers
28 views
What is the average luminance of the star background?
What is the luminance of the star background, i.e. of all the objects outside of the Solar system? E.g. if we measured average luminance of the sky from the far side of the Moon (so that solar and ...
2
votes
1answer
51 views
Why do brighter stars/planets appear physically larger?
Look at Sirius and then some 2nd magnitude star. Sirius appears physically larger despite both stars subtending approximately the same angular diameter.
Callisto is far enough from Jupiter at its ...
2
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1answer
66 views
When does a solar eclipse become noticeable?
For a human viewer located on Earth, is there an approximate apparent magnitude at which a solar eclipse becomes apparent in the form of a noticeable change in ambient brightness?
Assume normal ...
4
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67 views
In terms of power delivered to Earth, what is the brightest object in the sky?
I was reading about TXS 0506+056, a distant blazar. The Wikipedia article mentions it is one of the brightest objects in the sky at both gamma and radio frequencies. This got me wondering — if we ...
4
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1answer
132 views
Can a telescope ever increase the apparent luminance of an extended object?
From what I know about common telescope designs, telescopes don't increase the apparent luminance of extended objects compared to the luminance seen with the naked eye. In this sense extended objects ...
2
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1answer
52 views
Strip Brightness in a Spherical System
My question concerns the following problem, published in Galactic Dynamics by Binney and Tremaine and based on a work by Schwarzschild.
Specifically, I am having difficulties in deriving the given ...
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1answer
37 views
How imperceptible will the 4-July-2020 penumbral lunar eclipse be?
Wikipedia's July 2020 lunar eclipse; Visibility says:
It will be visible from some parts of North America during moonrise, South and North America, the extreme part of Namaqua Land in South Africa ...
1
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1answer
95 views
Is it possible to calculate how much a star's brightness dims when a planet transits in front of it from a viewer's perspective?
Last night I got to thinking about what would happen if Jupiter and Venus suddenly switched places.
Since Venus comes the closest to Earth than any other planet and Jupiter is much larger, does that ...
4
votes
1answer
439 views
How do we measure the brightness of the stars?
How do scientists measure the brightness of so distant stars?
