Questions tagged [brightness]
The brightness tag has no usage guidance.
15
questions
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1answer
74 views
What would shadows look like on a planet with two suns?
On planet Tatooine which has two (main-sequence I guess) suns people still have one shadow only. Tatooine's suns seem quite close to each other, so it may actually be the case that the two shadows are ...
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0answers
37 views
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
votes
1answer
97 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?
17
votes
1answer
964 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
83 views
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
votes
3answers
561 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
votes
0answers
31 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
53 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
92 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
votes
0answers
69 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
votes
1answer
140 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
votes
1answer
72 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 ...
1
vote
1answer
38 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
vote
1answer
115 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
661 views
How do we measure the brightness of the stars?
How do scientists measure the brightness of so distant stars?
