Some very basic Astronomy questions

[yalgaar]

I have some very basic atronomy questions that either I did not get answers to when I googled it or did not get very good explanation on the subject. So asking it here in this forum. I hope you guys do not mind answering such basics.


1) When I get out of my house at night and look at the sky at the certain degree while standing outside my door, will I see the same set of stars at any time of the night and any night of the year at the same degree? If the answer is "No" can you give me explanation of all the movements that are causing the starts to shift the position and how? i.e Earths rotation, Earths revolution, the Sun moving around center of Galaxy (while taking the Earth along)

2) Will people in Sothern and Northern Hemisphere see the same set of starts at night?

3) Will people in the East and West see the same set of starts at night?

4) There are few stars that I see at night, I would like to know more about those particular stars. i.e how far they are, have we named them? how big they are, etc etc. Where should I start looking about all of this?

 

[NobodySpecial]

will I see the same set of stars at any time of the night and any night of the year at the same degree?

Roughly - yes, the stars you see are randomly distributed
The stars you can see with your eye are all pretty close to us, so our position in the galaxy doesn't matter.

2) Will people in Sothern and Northern Hemisphere see the same set of starts at night?

Only the stars near the equator (ie low down in the northern sky) can be seen from both hemispheres. The ones higher above you can only be seen from your own bit of the world.

3) Will people in the East and West see the same set of starts at night?

Yes - just a few hours later.

4) There are few stars that I see at night, I would like to know more about those particular stars. i.e how far they are, have we named them? how big they are, etc etc. Where should I start looking about all of this?

The very brightest in the north tend to have Arabic names - mostly due to historical coincidence. They were the first people to name them whose books survived.
Then as more stars became visible with telescopes we needed a more organised system, so the stars were named with greek letters in order of brightness for each constellation.
so alpha-ori is the brightest (alpha is the first greek letter) star in the constellation orion - it's also called Betelgeuse.
Then there are lots of id numbers from different catalogs, each catalog maker giving them their own number.

See http://en.wikipedia.org/wiki/List_of_brightest_stars

 

[russ_watters]

Sorry, the answer to the first question is no. What stars you see is based on the Earth's rotation and revolution. The same set of stars is in the sky every day, but where and when depends on the date/time.

 

[yalgaar]

Thank you very much for all the answers. It has been really very helpful.

I have 1 more question. I live in USA, New Jersey. How do I located a certain star? For example how do I locate "Sirius"? Which direction I should be looking at what angle? How can I be sure?

 

[NobodySpecial]

Yes - Sorry about that I completely misread the question to be a more complex one about the distribution of stars - ie are there more stars in a particular direction.

There are some stars that are visible all year around - the circumpolar stars - these are high enough (almost overhead) that you can always see them on any night of the year. But most stars are only visible for part of the year from one hemisphere - as russ said.

There are lots of software packages and websites that show you a map of the sky for your location at any time (eg http://www.stellarium.org/ http://www.skyandtelescope.com/observing/ataglance/ )

 

[davenn]

Also, the star "groups" read constellations ... eg cancer, orion, virgo etc, etc you will see rising above the horizon at the same time each year (minus the small precession)
and this is what farmers used for countless centuries to know when to plant crops etc.
ie your summer or autumn, winter or spring constellations :)

Dave

 

[yaang]

1) When I get out of my house at night and look at the sky at the certain degree while standing outside my door, will I see the same set of stars at any time of the night and any night of the year at the same degree? If the answer is "No" can you give me explanation of all the movements that are causing the starts to shift the position and how? i.e Earths rotation, Earths revolution, the Sun moving around center of Galaxy (while taking the Earth along)

Answer is No. Every movement of Earth changes our direction hence change the stars we can see. First one is rotation around it's own axis which causes day/night cycles. If you take time and observe a star for a few hours you can clearly see it's movement. Second is rotation around sun which will change the stars you see depending on the season. There is also the lesser known movement the rotation of the Earth's axis itself. It also makes a circle but it takes too long to complete for us humans so we usually round it off (takes around 10 thousand years iirc) So that changes the stars you see depending on what year it is too. Sun moving around the galaxy should technically change the stars but i don't think it deals any observable change in human life spans.

2) Will people in Sothern and Northern Hemisphere see the same set of starts at night?

They won't because of Earth's sphere like shape

3) Will people in the East and West see the same set of starts at night?

Yes, just people in the east will see them earlier

4) There are few stars that I see at night, I would like to know more about those particular stars. i.e how far they are, have we named them? how big they are, etc etc. Where should I start looking about all of this?

What you want is a program called stellarium. You can get it from http://www.stellarium.org/
What this program does is after you enter where you are and set the time and date (program does all of these automatically) it shows you the sky you should be seeing at that location at that date and time. You can easily hover over a star and not only get it's name but plenty other stats too. It can also display constellations which makes them really easy to learn. Anyway try it yourself it's quite easy to use.

 

[Drakkith]

Do yourself a favor if you're really interested in this and go to a local bookstore and buy pretty much ANY book on amateur astronomy. I picked one up at Books a Milliion on the clearance section for about 5 bucks and it's great. A good one can show you what the sky will be like at each time of the year, and how to read starcharts and find celestial objects.