<p>At any given instant of time, in any place on Earth, if the sky is clear and the horizon is low and flat, you see half of the celestial sphere - at that very instant.</p>

<p>But as the Earth keeps turning, you may end up seeing more, depending on where you are.</p>

<p>If you're at the North or South Pole, you see exactly half of the sky no matter how long you wait. That's all you'll ever see from there.</p>

<p>If you move closer to the Equator, you'll end up seeing more than half, if you're willing to wait.</p>

<p>At the Equator, you see pretty much all the sky, if you wait as the Earth keeps spinning around, revealing all the sky to you eventually.</p>

CC BY-SA 3.0
2014-12-17T11:08:39.470Z
*"At the Equator, you see pretty much all the sky, if you wait as the Earth keeps spinning around, revealing all the sky to you eventually."* by this way the Equator is the only place that observers see the sky in a panorama ? **just may you tell me how much the height is effective here too ?**
Fereydoon Shekofte
CC BY-SA 3.0
2014-12-17T18:47:47.587Z
It's important, yes - but keep in mind that the extreme celestial North and South will be poorly visible from the Equator at any altitude. Anything close to horizon is hazy and unclear. So the North and South view will never be optimal - but at least you'll see something, if you're on top of a mountain, with clear atmosphere all around.
Florin Andrei
CC BY-SA 3.0
2014-12-16T18:22:20.977Z
2014-12-16T18:22:20.977Z
Florin Andrei
<p>Is this the following statement true?</p>

<blockquote>
  <p>An observer on earth only may see half of sky from the northern or southern hemisphere, and even if the observer stands on the equator on top of a very high mountain, he will hardly be able to see all the stars in the sky in given period!</p>
</blockquote>

<p>Do most globe-like objects in space have this property?</p>

<p>I'd appreciate any more remarks on the subject.</p>

<observational-astronomy>
Can an observer on Earth only see half of the sky?
Fereydoon Shekofte
# Can an observer on Earth only see half of the sky?

(Asked by: username_0 on 2014-12-16)

Is this the following statement true?

> An observer on earth only may see half of sky from the northern or southern hemisphere, and even if the observer stands on the equator on top of a very high mountain, he will hardly be able to see all the stars in the sky in given period!

Do most globe-like objects in space have this property?

I'd appreciate any more remarks on the subject.

**Tags:** observational-astronomy


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## 1 answers

### Answer by username_1 on 2014-12-16. Score: 6 | Accepted answer

At any given instant of time, in any place on Earth, if the sky is clear and the horizon is low and flat, you see half of the celestial sphere - at that very instant.

But as the Earth keeps turning, you may end up seeing more, depending on where you are.

If you're at the North or South Pole, you see exactly half of the sky no matter how long you wait. That's all you'll ever see from there.

If you move closer to the Equator, you'll end up seeing more than half, if you're willing to wait.

At the Equator, you see pretty much all the sky, if you wait as the Earth keeps spinning around, revealing all the sky to you eventually.

> **Comments:**
> **username_0**: *"At the Equator, you see pretty much all the sky, if you wait as the Earth keeps spinning around, revealing all the sky to you eventually."* by this way the Equator is the only place that observers see the sky in a panorama ? **just may you tell me how much the height is effective here too ?**  
> **username_1**: It's important, yes - but keep in mind that the extreme celestial North and South will be poorly visible from the Equator at any altitude. Anything close to horizon is hazy and unclear. So the North and South view will never be optimal - but at least you'll see something, if you're on top of a mountain, with clear atmosphere all around.  

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