Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange
Join us in building a kind, collaborative learning community via our updated Code of Conduct.

Questions about observations performed without the aid of any optical instrument.

2
votes
2answers
31 views

What is “class 4 light pollution” and could I estimate my own area's class visually?

This question currently asks I am living in the northern hemisphere in Greece and in class 4 area (light pollution scale).Is it possible to see the Andromeda galaxy with a naked eye? I'd never ...
5
votes
2answers
139 views

Is it possible to view the Andromeda galaxy with the naked eye in Greece?

I am living in the northern hemisphere in Greece and in class 4 area (light pollution scale). Is it possible to see the Andromeda galaxy with a naked eye?
3
votes
3answers
88 views

Why is the color of the moon so similar to the clouds?

Why the moon looks like the cloud-structure on the blue sky among the clouds?
5
votes
1answer
152 views

Mars night sky — Phobos and Deimos?

I'm having a debate about how bright Martian nights would be, in terms of both the sky itself and ground illumination. This answer seems to indicate that the stars would be only dimly visible, and ...
58
votes
2answers
11k views

Could the dinosaurs have seen the asteroid that killed them?

Wikipedia says the Chicxulub impactor is thought to have been a 10-15 km diameter object. Would it have been visible to a (human*) naked eye before impact? And if so, would it have appeared like a ...
1
vote
3answers
147 views

Will we be able to see our galaxy if we travel far enough?

Will we be able to see our galaxy if we travel far enough? When we leave earth far enough, we'll be able to see Earth from distant, is it same with the galaxy? if we travel far enough, will we see the ...
1
vote
0answers
36 views

Does the position of the sun in your visual field affect the risk of photic retinopathy?

"Don't stare at the sun or you'll go blind" goes the adage. And yes when looking at the sun, you risk the intense light damaging your retina (photic retinopathy). Directly staring risks the macula. ...
1
vote
0answers
25 views

SkyGazer 4, observing the sun on increments of a day for one year

I am using the SkyGazer 4 CD application. I am asked to describe what I see on time increments of 1 day for one year. My initial start time was December 21, 2012 at 6:50 am looking east in San ...
0
votes
1answer
71 views

What was this red deep sky object? [closed]

I was looking through sky yesterday and saw something red in sky (naked eye ) like nebula or something then tried using stellarium and mobile observatory apps to find out what it was, But couldnt find ...
0
votes
1answer
73 views

Why isn't our local interstellar space colorised?

Looking at answers to this question, people seem pretty convinced that human naked eye should be able to see the colour of ionised gas/dust cloud when they are inside an emission nebula. And we know ...
9
votes
2answers
358 views

How easy would be to see the Moon from Mars?

This question arises from "What planet is better than earth to infer solar system configuration?", where one of the answers pointed that it's easier to discover the Moon from Mars than discovering the ...
28
votes
3answers
5k views

Is the Sun visible from Proxima Centauri to human eyes?

I know that the light coming from Proxima Centauri is not bright enough to make it naked-eye visible from the Earth. Is the Sun naked-eye visible from Proxima Centauri?
6
votes
1answer
2k views

Have there been successful attempts at spotting Neptune with the naked eye?

As pointed out here, the limit of naked eye visibility for people with extremely good night vision is about magnitude 8.5. Neptune at opposition is much brighter at magnitude 7.7, so it should be ...
0
votes
2answers
179 views

Tunnel vision while viewing through a reflector

I have a Celestron astromaster130 eq. While viewing through its eyepiece, or using a smartphone camera for photography purpose there is always a definitive no light region( it is circular in curvature)...
5
votes
3answers
174 views

Good textbooks for a descriptive astronomy course

Brief tale of woe My department at a small public university in the US has decided to begin offering a descriptive astronomy general education course for the first time in a couple of decades and we ...
1
vote
1answer
219 views

Seconds of Arc and the Unaided Eye

I've been presented with this problem: Say that Jupiter, with its diameter of 142,000 km, was located where Mars now orbits. What would be the angular size of (the newly-relocated) Jupiter ...
3
votes
1answer
550 views

The colour of saturn as it appears to the naked eye

I have started to watch the skies in order to learn stars, constellations planets etc. The few references I checked state that Saturn presents itself to the naked eye as a pale yellow tiny little ball,...
5
votes
1answer
430 views

Stars in the sky

Are the stars we can see with the naked eye in the night sky only from our Milky Way galaxy or can we see stars from Andromeda? I am aware we can see other celestial objects like nebulas and the ...
0
votes
0answers
216 views

How strong does a light source on the Moon have to be to be visible from Earth? [duplicate]

Flashes from some meteoroid impacts on the Moon can be seen with the naked eye. How much light must a future lunar base emit in order to be visible as a dot in the lunar night (like the flag of ...
1
vote
3answers
5k views

How much of the Milky Way is visible to the naked eye from earth?

When we see the Milky Way on a dark night are we seeing the bulk of the galaxy, or just our local arm? How much of the milky way is visible to the naked eye on a dark night?
6
votes
1answer
639 views

Mars night sky - how many stars visible?

How would the night sky look like from the Martian surface? Would there be more stars visible or less (compared to Earth)? Would they appear brighter/dimmer/same?
3
votes
1answer
497 views

Sky view from Stellarium software vs. Sky view with naked eye

I'm slowly starting to interest in astronomy. Currently I'm enjoying in stargazing but unfortunately place where I live is very light polluted. I'm planing my vacation in a couple of months and one ...
5
votes
3answers
252 views

How many stars can be seen naked eye from outside the atmosphere? How dense is the “sky” from there?

When I was 20, I went to Naxos (Greece) with friends. I was driving my car during the night on the mount Zeus (1003 meters - 3,291 ft) listening Pink Floyd. Up there we stopped the car to take a walk,...
4
votes
1answer
313 views

How bright are the outer planets, when at close range?

Seven probes have passed by or orbited outer planets. I wonder how their photos differ from the naked eye view one would have if one were actually there. Saturn is 10 AU from the Sun, which means ...
1
vote
3answers
84 views

Does naked eye miss a lot between local stars and distant milkiness?

When I look at the night sky I seem to resolve points which are local stars and milkiness at further regions of the galaxy. But what is between? I think there must be a lot of stars which are too ...
2
votes
2answers
2k views

Why does the Moon sometimes look Yellow?

My friend and I both noticed that the Moon looked yellow Yesterday, but it wasn't like that the same time the day before, as far as I remember. Does the Moon sometimes look Yellow? If it does, why ...
9
votes
3answers
762 views

Aren't there more naked-eye-visible stars in the Milky Way plane?

Most stars which are visible to the naked eye are within 1,000 light years. The Sun is inside the Orion arm which has a diameter of about 3,500 light years. Thus, all stars (with very few exceptions) ...
4
votes
1answer
2k views

What is the apparent magnitude limit for the naked eye?

If you only read the question, you will answer: ''That depends on the light pollution''. Yes, it does, but if you are in the darkest night sky (Bortle class 1), what magnitude would have the faintest ...
61
votes
4answers
8k views

Is the moon only 60 pixels?

In doing research on vision, I have learned that "20/20" vision corresponds to a visual acuity of being able to resolve details 1 arcminute in size, that most people have around 20/15 vision, and that ...
16
votes
1answer
8k views

How many stars and galaxies can be seen by the naked eye?

How many of the luminous dots that we see naked are galaxies and not stars from our galaxy? I imagine that the majority of the luminous points that we see naked eye during the night, are actually ...