# Constellations



## mulierrex (Sep 30, 2016)

I tried Googling this, but it only gave me north/south hemispheres.

My planet is an ordinary sphere -- or close enough --, but there are only habitable land masses in the northern hemisphere. 

Would people living in those places see constellations in the same position every night? In terms of our world, do people in Kazakhstan see the constellations the exact same way someone in California might (as long as it's nighttime of course)?

I really don't know if this is common knowledge and I sound dumb asking, but, here we go anyway...


----------



## CupofJoe (Oct 1, 2016)

Yes and No.
The constellations are the same wherever you are on the earth, but their place in the sky changes every night as the earth changes position around the sun. And they change where you are up and down the Earth. The thing that got me was seeing the pole star almost over head when I went to the Arctic Circle, I was used to thinking it over-that-away [waves had vaguely]. I hadn't realised that what you see in the sky is totally dependent on where you are on the Earth. What it must be like to see the polar star on the horizon if you are at the equator? So strange if you aren't used to it.
There are long term changes in the relative position and shapes of the constellations so the sky an ancient Greek saw is not those that we see. They are pretty much the same but they might have drifted and warped a bit. I read recently that our Star Signs [Leo, Sagittarius etc] are 3 weeks earlier [or later - I can't remember] than the Greeks would expect them.


----------



## skip.knox (Oct 1, 2016)

So, people in the same place at the same time of night would see the same stars. People in places that were sufficiently far away would see something different: if they were different east-west (this assumes a planetary rotation similar to ours), they would see the same but at different times of the evening, If they were different north-south, they would see stars appear at a different point in the sky. If sufficiently far apart north-south, they might actually see entirely different stars.

And, thanks to the precession of the equinox (which sounds rather like a movement in a symphony), people in the exact same placed at the same time would see something slightly different from people five thousand years in the past (because the planet does not spin perfectly on its axis but wobbles a bit).

To put all that in perspective. people in various parts of Europe (let's leave aside Scandinavia) see pretty much the same set of stars. Differences become meaningful when you're talking Canada versus Ecuador versus Australia.


----------



## K.S. Crooks (Oct 2, 2016)

They would see the same constellations over the course of a year if they live at the same latitude. Night to night the stars will start in a position farther east or west, depending on your planet's rotation direction. The closer or farther from the equator or pole will change which and how much of certain constellations someone sees.


----------

