True or false: The nighttime sky view completely changes every six months from any given location on earth?

Question

As I imagine it in my head I'm on a tilted globe in orbit and I'm in Portland Oregon on March 21st I look up at the night sky and see several constellations. Then on September 21st I look up at the night sky again is it possible for me to see any of the same constellations? I would think it is impossible from any given point on Earth to see the same constellations that you saw 6 months prior. Yet, there are year round constellations. How is this possible?

Answer 1

Technically yes, but even theclosest obect are twoo far away to realize it

Answer 2

False.

Answer 3

False. The further you are from the equator, the less it changes. At the Poles - it doesn’t change at all.

Answer 4

What you say is true if you look at the night sky at the same hour of night in March and September. But actually, when skies are clear, you can generally see ~80% of the constellations that are visible from your location on any given night. It is just that the times of visibility will be different. The only factor that keeps you from seeing 100% of the sky is the glare from the Sun, which obscures about 20% of the celestial sphere. For instance, you might be able to see Scorpius just after sunset, and then not see it for a couple of months, and then see it again in the hour just before sunrise, maybe two months later.

Cheers

Answer 5

False.



You're in Portland, so you're at 45.5 degrees north. You are able to see Polaris, the Pole Star, at 45.5 degrees above the horizon. As the Earth spins once a day, all the other stars will appear to rotate around it. Anything closer to the Pole than 45.5 degrees away will always be above the horizon and always visible. We call these circumpolar stars and constellations. They will get low down and close to the horizon but never dip below it.



Anything further away, however, will dip below the horizon at some time. So these stars will only be visible at certain times. And anything closer than 45.5 degrees away from the South Pole of the sky will never rise above the horizon at all. If you want to see those, plan a trip to Australia! (Which will demonstrate a few other things too - the Moon looks upside down from there, and its phases occur the "wrong way round". Figure that one out!)



All that changes at different times of year is which non-circumpolar stars we can see, because we're travelling around the Sun so as the year progresses, different parts of the sky are above the horizon at night. If we could turn the Sun off for a day, then you'd be able to see all possible stars you can ever see from Portland at some time during that 24 hours, though not all at the same time. All that changes is which of them you can see at night. And so there are constellations known as seasonal. For example, Orion, which is not circumpolar at your latitude and definitely a sign of winter. In summer, it's above the horizon during the day so you can't see it, but there are other constellations you can't see in winter.



I'm in London, England, about 52 degrees north, so there is a bit more that is circumpolar here. Polaris appears a little higher in the sky than it does in Portland. (That is, when you can see it at all - on our damp island, the view is so often blocked by clouds! Which is why we have no major telescopes. It would be a huge waste of money and so British astronomers tend to travel a lot to where the "seeing" is better. I had a friend at university whose personal tutor was an astronomer and he was so often away in Hawaii - nice work if you can get it!)



To go to the extreme, let's make an imaginary visit to the North Pole. Polaris will be directly overhead, and everything will be circumpolar. The sky view will be the same every night all year, and all that changes is what compass direction any star or constellation is in. We can't see any constellations on the south side of the equator of the sky, EVER.



For the other extreme, let's visit somewhere on the Equator. Polaris will be on the horizon, nothing is circumpolar, and then it would be true that the constellations you see are exactly the ones you couldn't see six months before. And over the course of a year, you would be able to see every constellation there is. That's the only place your statement would be true.

Answer 6

You can download stellarium and after a little learning how to use it you can watch the night sky from any point on earth in a timelapse if you want to.

Answer 7

False: The night time sky view completely changes every few hours due to the rotation of the Earth. Just after dark you will see a constellation rise and during the night it will continue overhead and you see others set and rise. This time of Year you can see ORION in the late evening,

Answer 8

No it doesn't. The only locations on Earth where this would happen would be on the equator. Everywhere else there are stars which never set but appear to describe circles in the sky around the north celestial pole. From where you are an example would be Ursa Major.

Answer 9

Neither your orientation by that I mean the axis of daily rotation of earth nor the location of earth in the whole of cosmos is the same. In India in winter season we see milky way as a bright patch spread from scorpion constellation to big dipper. but in summer the patch is not as bright. The reason for this is that in night in winter we on earth look towards the center of the milky way opposite to the location of sun but after six months in the night we look towards the edges of the milky way opposite to the location of sun.

Answer 10

Since you live in the Northern hemisphere, have you heard of the constellations Big Dipper and Little Dipper?