I need help with Right assension and declination?

Question

I can't quite understand it. How do I find 0hr at different points during the night?

I know i spelled it wrong

Answer 1

Right ascension and declination are just like longitude and latitude, but in the sky instead of on Earth. The stars are fixed on this grid, so if you know the right ascension of any star then you can measure from that star to any other point. If you want to know the right ascension of the meridian at your location, or the hour angle of the vernal equinox, which is 0hr, you need to know the local sidereal time. The US Naval observatory has an online calculator. Of course local sidereal time is changing continuously as the Earth rotates, so at the moment you determine the local sidereal time you need to start a clock and later add whatever that clock says to the value you originally got to have the current local sidereal time. Also, the clock should really be a sidereal clock and not a solar clock, because a solar day is 24 hours but a sidereal day is only 23h 56m 4s, although a regular solar clock is probably good enough for a few hours. The difference is due to the Earth's orbit. Earth rotates once in 23h 56m 4s but in that time it has moved around the Sun enough so that it needs to rotate another 3m 56s to bring the Sun back to the same altitude in the sky. Another way to look at it is that the sun moved 3m 56s in right ascension during the day.

Answer 2

Believe it or not, I've managed 14 years without ever using the setting circles on my telescope...that is, aside from the short one night go at it wherease I decided my old way, with SkyMap, a pair of binoculars, and a good memory was far superior when it came to finding things in the sky.

Here's how to do it the "right" way though.
http://www.telescopesa.za.org/TGHHowTo1.htm

Have fun.