How much of the celestial sphere can an Earth observer see at one time?

Answer 1

Approximately 50% like anywhere else on the planet. The difference at the poles is that it is the same 50% all night and all year.

The reason it is approximate is that:

1/ If you are high up you will see a little more than 50% due to the curve of the Earth.

2/ If the land around you has hills they will block some of your view reducing the percentage a little.

Answer 2

Half.

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But the amount of it that you're ever able to see depends on where you live ...

specifically, your latitude, i.e. how far you are from the equator.

If you're at the north or south pole, then you see half of the entire sky whenever

it's dark enough. The center of it is directly over your head. Everything rotates

around that center, never getting any higher or lower off the horizon, and you

never see any of the other half. (By the way, since you're at the pole, you get

all of your dark time all at once. The sun is up for 6 months and down for 6

months, and it's probably dark enough to see stars for only maybe 4 or 5

months out of those six ... out of which 2 or 3 are too cold to go outside, or

the sky is overcast, or full of blowing snow. Astronomers do not pine for an

observatory at the north or south poles.) )

If you're on the equator, then you also see half of the entire sky whenever it's

dark enough. The center of it is on your northern (and southern) horizon.

Everything rotates around that center like a barrel, rising in the east, setting

in the west 12 hours later, and over the course of few months, you can see

everything in every part of the sky, at some time during the night.

If you're in between the equator and a pole, then you can see half of the entire

sky whenever it's dark enough. The center of it is somewhere on a slant between

your horizon and the point over your head. The angle between the horizon and

that center-point is the same angle as your latitude, and the whole sky turns

around that center.

Since the center-point is on a slant . . .

-- some things in the sky that are close enough to it never get low enough to set;

-- some things in the sky that are so far from it in the other direction never rise,

and you can never see them from where you are;

-- everything else in your sky, between these two circular areas, rises and sets.

The whole action shifts about 4 minutes earlier every night, so the parts that are

only up during the day right now will eventually be up during the night if you wait

a few weeks or months.

Answer 3

Half the sky, if you have a clear view (no mountains, for instance).

Half the sky, if you have a clear view (no mountains, for instance).

Half the sky, if you have a clear view (no mountains, for instance).

Half the sky, if you have a clear view (no mountains, for instance).

Answer 4

Half, minus the percentage of cloud cover. During the day, the atmospheric glare drowns out all but the Sun, Moon and (if it's up) Venus.

Unless your on the equator then you can see the entire Celestial Sphere

Answer 5

Right now? September 5, 2010? None at all; the Sun is still up at the North Pole, and will be until September 21. And the Sun won't be far enough below the horizon to see stars for another week or so after that. (Aside from the fact that there is nobody at the North Pole.)

After mid-October, if there were any people there to look, they would be able to see about half of all the visible stars.

Answer 6

No. An observer at the North Pole can see only half of the celestial sphere.

No matter where you are on Earth, there is only so much of the celestial sphere that you can see.

(Comments: Actually you can see the whole celestial sphere from the equator, but

you would not be able to see all the stars on any one particular night.)

Answer 7

It is all of the 88 constellations around the Earth forming a sphere.

Answer 8

0% of them. All stars visible from the north pole are at or below the horizon from the south pole and vice versa.

Answer 9

only one half of the sky that is north of the celestial equator is ever visible at the north pole

Answer 10

it depends on ware you live. how much light pollution there is.