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Questions tagged [atmospheric-effects]

Questions about the influences of Earth's atmosphere on astronomical observations.

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27 votes
4 answers
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Terrestrial Exoplanet Skies – I've Built a Visual Sky Chart. Is it Accurate?

I'm an artist (and science enthusiast) and I've been trying to find a comprehensive resource that would help me clearly identify likely sky colors (as perceived by human vision) for exoplanets that ...
n_bandit's user avatar
  • 625
4 votes
1 answer
188 views

What can be learned from low frequency radio astronomy available outside of Earth's ionosphere?

As discussions and answers to How large does refraction become in radioastronomy? point out, it is difficult to do radio astronomy much below 30 MHz (or 10 MHz depending on how aggressive you are in ...
uhoh's user avatar
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37 votes
2 answers
9k views

Why doesn't the moon twinkle?

Stars twinkle because their light has to squeeze through several different layers of the Earth's atmosphere. So why doesn't the moon twinkle as well?
Ricky's user avatar
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7 votes
2 answers
628 views

How large does refraction become in radioastronomy?

For atmospheric refraction of visible light, Wikipedia gives the order of 1 arc minute at 45° altitude above the horizon, and 5.3 arc minutes at 10°. This is caused by the dielectric polarizability of ...
uhoh's user avatar
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5 votes
1 answer
131 views

When are wedge prisms used to correct chromatic effects of atmospheric refraction? (atmospheric dispersion)

Atmospheric refraction (shown below) happens because Earth's atmosphere has an index of refraction that differs from unity. @MikeG's comment mentions that this refraction would have a chromatic ...
uhoh's user avatar
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4 votes
3 answers
2k views

What color is the Sky on other Planets?

On Earth, the sky is blue. What color would the sky be on other planets in our solar system? What about outside the solar system? Are there planets with purple skies, or green skies? Or are the all ...
PotatoLatte's user avatar
3 votes
1 answer
693 views

Do the gases in the Earth's atmosphere affect the color of a lunar eclipse?

As the sun's rays pass through the Earth's atmosphere only the red light gets through. Is this the result of specific gases in the Earth's atmosphere filtering the red light? Does all of the nitrogen ...
Gliese's user avatar
  • 831
3 votes
1 answer
168 views

Why could I so easily see and photograph such a bright totally eclipsed Moon from a bright city road? (May 26, 2021 total lunar eclipse)

Due to scheduling and geometry I could only snap last night's lunar eclipse with an older model cell phone on a pedestrian overpass of a brightly lit city street, but surprisingly the Moon was quite ...
uhoh's user avatar
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1 vote
1 answer
526 views

Can an average person see stars from the bottom of a well or through cardboard tubes? Definitive answer required!

A debate about seeing stars or planet during the day below this answer to the Aviation SE question At what altitude might a pilot be able to see at least the brightest stars during the day? seems ...
uhoh's user avatar
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34 votes
2 answers
2k views

How could a hobbyist astronomer determine apparent magnitude of a star?

Apparent magnitude is a rather complex way to determine the brightness of a star. Quoting the introduction text from the linked to Wikipedia page: The apparent magnitude (m) of a celestial body is ...
TildalWave's user avatar
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13 votes
2 answers
363 views

What was the first astronomical measurement which demonstrated that "the Earth is surrounded by vacuum"?

The question Who was the first to realize that the Earth is surrounded by vacuum? was closed because some users felt it was answered by answers to a different question in an different SE site: Who was ...
uhoh's user avatar
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7 votes
2 answers
392 views

How will "modern equipment" allow the Royal Observatory to now avoid some of the effects of light pollution at Greenwich?

The article First Light: a new era for the Royal Observatory says (in part): 25 June 2018 The first modern, research-grade telescopes have just been installed at the Royal Observatory Greenwich, ...
uhoh's user avatar
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4 votes
1 answer
868 views

Under what situations can an aperture mask improve the resolution of a small/medium amateur telescope? Is this demonstrable mathematically?

@antlersoft's answer describes some of the challenges to seeing any details in the small disk of Mars in small amateur telescopes. In the case of reflecting telescopes, it mentions the use of either ...
uhoh's user avatar
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3 votes
1 answer
195 views

Would an extremely bright star produce same kind of shadow band effect as seen in solar eclipses just before totality?

This answer to What is causing this strange shimmering pattern of light during a total solar eclipse? explains that the shimmering patterns seen on surfaces at the moment before totality of a solar ...
uhoh's user avatar
  • 30.7k
0 votes
1 answer
215 views

Why is the opening in the Anglo-Australian Telescope's dome so small?

Many older or "classic" telescope domes have a horizon-to-zenith opening in the dome, and this helps speed up the thermal equilibration between the inside and outside air, decreasing turbulence and ...
uhoh's user avatar
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54 votes
5 answers
20k views

Why is moon light not the same color as sunlight?

The light from the moon is light being reflected from the sun. The sun, in space, is white. But on Earth, when the light is filtered through an atmosphere, the light appears yellow. So then, why is ...
Andrew Johnson's user avatar
17 votes
1 answer
1k views

How much clearer are stars in earths orbit?

As a child I remember my parents taking camping in California, and upon stepping out of the car I was awestruck at how thick the Milky Way galaxy was and at the number of stars everywhere. I've always ...
Paul's user avatar
  • 377
12 votes
1 answer
417 views

How would astronomical seeing on Mars differ from that on Earth?

Astronomical seeing is the limiting factor for the resolution of all but the smallest Earthbound telescopes. Source Stunning advances in adaptive optics (along with it's predecessor speckle ...
uhoh's user avatar
  • 30.7k
7 votes
0 answers
150 views

Can terrestrial infrared telescopes see through clouds or haze, sometimes at least?

My answer to Could UV-A imaging sensor reasonably see a total eclipse in progress through clouds? suggests that while clouds blocking visible light observation of the (partially) eclipsed solar disk ...
uhoh's user avatar
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5 votes
1 answer
2k views

What is causing this strange shimmering pattern of light during a total solar eclipse?

Below this question was left a comment linking to the Smarter Every Day video Space Station Transiting 2017 ECLIPSE, My Brain Stopped Working - Smarter Every Day 175. At about ...
uhoh's user avatar
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5 votes
1 answer
751 views

Would a red dwarf star resemble our own Sun at sunset to an observer on a nearby planet?

Suppose you're observing a red dwarf star at Noon from the surface of an Earth-like planet orbiting in the red dwarf's habitable zone, so that the red dwarf's luminosity is equal to our own Sun. Aside ...
RobertF's user avatar
  • 183
4 votes
3 answers
111 views

Fixed star-like light appears for a second or two - is there a way to find out what it was?

I saw what I can only describe as a fixed point of light, as bright as a shooting star, near Alpheratz for a second or two before disappearing. I am positive it wasn't a satellite nor a plane. There ...
Erken's user avatar
  • 143
3 votes
1 answer
79 views

Why would atmospheric absorption increase rather than decrease the antenna temperature in Penzias and Wilson's famous CMB observation?

The classic paper A MEASUREMENT OF EXCESS ANTENNA TEMPERATURE AT 4080 Mc/s begins: Measurements of the effective zenith noise temperature of the 20-foot horn-reflector antenna (Crawford, Hogg, and ...
Youngsub Yoon's user avatar
3 votes
2 answers
215 views

Venus Atmosphere Color

I want to ask what color is the Venusian atmosphere without the presence of dense clouds for our human vision? I searched for this question, and did not find a suitable answer. Everywhere they write ...
Mikee's user avatar
  • 51
3 votes
2 answers
288 views

Which kinds of astronomical observations most need to avoid the Moon being up?

This comment to Did nobody in the Astronomy community think 12,000 new satellites in LEO might be a problem? links to Phys.org's New ESO study evaluates impact of satellite constellations on ...
uhoh's user avatar
  • 30.7k
2 votes
0 answers
133 views

Has "crescent-twinkling" even been demonstrated or at least calculated/predicted? Any "twinkleometer" data for Venus out there?

My new answer to Why does Venus flicker? addresses something that I find particularly interesting; Venus can be an incredibly thin crescent at times, and even a 1 arcminute large thin ring with an ...
uhoh's user avatar
  • 30.7k
2 votes
1 answer
191 views

Long term temperature effects of an eclipse

I was surprised to see a very measurable difference in temperature at my home during the recent solar eclipse. The temperature was about 93 degrees fahrenheit but dropped to around 86 degrees. It ...
Maelish's user avatar
  • 323
1 vote
2 answers
392 views

Around what apparent magnitude can the naked eye observe an object during full moon

For a very rough guideline using healthy/corrected eyes adjusted to the dark, around how bright should an object be to expect it to be visible?
Louis Waweru's user avatar
1 vote
1 answer
121 views

Was is the angle needed to see a glory (a rainbow-like effect) from space off the Earth? [closed]

What positions would the Earth, Sun and viewer need to be to see a glory (a rainbow-like effect) from space? What position would they need to be in to reproduce this picture? Source: Gizmodo (NASA ...
Muze's user avatar
  • 1