Transparency and Atmospheric Extinction

[Bigzmey]

Here is a nice article on how apparent brightness of a target is affected by observing conditions

https://www.skyandtelescope.com/astrono ... xtinction/

[Don Quixote]

Thank you Andrey.
I have enjoyed this article very much.

Now...how do we explain why, when through a telescope we do not receive all the light either, that is to say that a star is never brighter than what we see naked eye, we are able to see stars that are unavailable, "extincted" to the naked eye view, through that telescope?

Wow...I'm not even sure I understand my own question...!

[Bigzmey]

Thank you Andrey.
I have enjoyed this article very much.

Now...how do we explain why, when through a telescope we do not receive all the light either, that is to say that a star is never brighter than what we see naked eye, we are able to see stars that are unavailable, "extincted" to the naked eye view, through that telescope?

Wow...I'm not even sure I understand my own question...!

Textbook explanation is that telescope takes light over the larger area (lens aperture) and focuses it to smaller area (exit pupil) thus increasing the target brightness.

Alternative explanation is that stars as point sources of light have the same brightness over the range of magnifications, while sky background gets darker at higher powers. This is why even with the same scope you can resolve fainter stars pushing to the higher powers.

[Don Quixote]

Thank you Andrey.

[notFritzArgelander]

Thank you Andrey.
I have enjoyed this article very much.

Now...how do we explain why, when through a telescope we do not receive all the light either, that is to say that a star is never brighter than what we see naked eye, we are able to see stars that are unavailable, "extincted" to the naked eye view, through that telescope?

Wow...I'm not even sure I understand my own question...!

Textbook explanation is that telescope takes light over the larger area (lens aperture) and focuses it to smaller area (exit pupil) thus increasing the target brightness.

Alternative explanation is that stars as point sources of light have the same brightness over the range of magnifications, while sky background gets darker at higher powers. This is why even with the same scope you can resolve fainter stars pushing to the higher powers.

Until you can resolve the Airy disk, then brightness decreases in the usual way.

The "textbook explanation" oversimplifies a bit. The "alternative explanation" simplifies less.

One has to be careful about "brightness". It has a physics definition and also there are physiological factors.

In terms of something like "magnitudes per square arc second on the sky" brightness is always decreased by telescopes. The telescope, used visually, is a contrast enhancer even while brightness is decreased. That's why the "alternative explanation" is less of a falsehood than the oversimplified "textbook explanation".

https://clarkvision.com/visastro/index.html

https://clarkvision.com/visastro/m51-apert/

[Bigzmey]

Thank you Andrey.
I have enjoyed this article very much.

Now...how do we explain why, when through a telescope we do not receive all the light either, that is to say that a star is never brighter than what we see naked eye, we are able to see stars that are unavailable, "extincted" to the naked eye view, through that telescope?

Wow...I'm not even sure I understand my own question...!

Textbook explanation is that telescope takes light over the larger area (lens aperture) and focuses it to smaller area (exit pupil) thus increasing the target brightness.

Alternative explanation is that stars as point sources of light have the same brightness over the range of magnifications, while sky background gets darker at higher powers. This is why even with the same scope you can resolve fainter stars pushing to the higher powers.

Until you can resolve the Airy disk, then brightness decreases in the usual way.

The "textbook explanation" oversimplifies a bit. The "alternative explanation" simplifies less.

As long as it works.

[notFritzArgelander]

Textbook explanation is that telescope takes light over the larger area (lens aperture) and focuses it to smaller area (exit pupil) thus increasing the target brightness.

Alternative explanation is that stars as point sources of light have the same brightness over the range of magnifications, while sky background gets darker at higher powers. This is why even with the same scope you can resolve fainter stars pushing to the higher powers.

Until you can resolve the Airy disk, then brightness decreases in the usual way.

The "textbook explanation" oversimplifies a bit. The "alternative explanation" simplifies less.

As long as it works.

Which is the problem with simplified explanations. They don't work at some point.

[Bigzmey]

Until you can resolve the Airy disk, then brightness decreases in the usual way.

The "textbook explanation" oversimplifies a bit. The "alternative explanation" simplifies less.

As long as it works.

Which is the problem with simplified explanations. They don't work at some point.

I meant telescope not the explanations.

[notFritzArgelander]

As long as it works.

Which is the problem with simplified explanations. They don't work at some point.

I meant telescope not the explanations.

Ah, I thought we were discussing an explanation of how telescopes work?