intersection of the Celestial equator and Meridian...

[toc (Tim)]

Newbie question, but would I be right in thinking that the intersection of the Celestial equator and Meridian is close to overhead?

[toc (Tim)]

...or is it simply the south celestial pole?

[Jon (Jonathan)]

Originally Posted by toc

Newbie question, but would I be right in thinking that the intersection of the Celestial equator and Meridian is close to overhead?

It would be exactly overhead if you were at the equator.

The intersection of the celestial equator and the meridian is due north, at an altitude equal to 90-your latitude. So if you're in Melbourne, latitude 37 degrees S, it's 63 degrees above the horizon.

[Jon (Jonathan)]

Originally Posted by toc

...or is it simply the south celestial pole?

Nope. If you were facing the intersection of the meridian and the celestial equator, your back would be to the South Celestial Pole. It's due South (obviously), at an altitude above the horizon equal to your latitude.

If you drew a line from the SCP to the intersection of the celestial equator and the meridian, it would traverse exactly 90 degrees of sky and pass through the point directly over head (the point directly overhead is known as the zenith).

[chiaroscuro (Luke)]

Originally Posted by Jon

It would be exactly overhead if you were at the equator.

The intersection of the celestial equator and the meridian is due north, at an altitude equal to 90-your latitude. So if you're in Melbourne, latitude 37 degrees S, it's 63 degrees above the horizon.

Thats 53 degrees.

Luke

[Jon (Jonathan)]

Originally Posted by chiaroscuro

Thats 53 degrees.

Luke

You know, I do believe you may be right

[toc (Tim)]

Thanks

[bkm2304 (Richard Brown)]

Here's a cute way to get an idea of the celestial pole position.

Pretend you are on the equator in Indonesia, say. Face west.
Extend your arms to shoulder level so your left arm points to the southern horizon and right to the northern horizon.

Your extended arms are pointing at the two celestial,poles.

Now in your minds eye start to head south. As you do, slowly raise your left arm and at the same time drop your right arm by the same amount By the time you are at the South Pole your left arm is pointing straight up and your right is through the floor below your feet. So the South Pole is 90 degrees south, ie 90 degrees above the horizon. So now just move your arms to your latitude. I live close to 33 degrees south so my left arm will be pointing 33 degrees above the southern horizon and my right arm 33 degrees below the northern horizon.

If you think about it, that means that I can see stars as far north as 57 degrees north. Ie a star that is on the northern horizon is 57 degrees north. In fact that is almost unseeable with the atmosphere clogging the view so low.
hope this helps.

Richard