any tutorials for using RA, DEC

[alphamone]

My new scope has an EQ mount, and i was just wondering how I use those numbers on the wheels to point at what I want to, and how I take time of day (and possibly year, dont know how this works yet)?

any help will be greatly appreciated.

[sheeny]

G'Day Alphamone!

:welcome: to IIS!

Let's start with the easy one first. Declination is like latitude on the Earth. A positive number is degrees north of the equator and the negative declination is degrees south of the equator. So a celestial body with a declination equal to your latitude will pass directly overhead at some time (once a day;):)).

Right Ascension (RA) is the celestial equivalent of longitude, but it is usually measured in units of time (hours, minutes and seconds) rather than degrees, arcminutes and arcseconds (but sometimes it can be measured in degrees, etc). For your setting circles, it is probably in hours, minutes and seconds.

24 hours equals 1 day or 360 degrees of rotation of the earth. So 1 hour equals 15 degrees.

You will notice that your RA circle can be moved. You should be able to spin it around the RA axis to show any value of RA that you want.

To use your setting circles, aim your scope at a star that you know the position of. The declination circle should read the correct declination of the star (if you mount is polar aligned accurately). Then you adjust the RA circle until the RA of the star is reading on the RA circle. From then on you should not need to adjust the RA circle, you should be able to use it to find objects or to measure the position of objects you observe - at least for that session anyway:P if you have an RA drive to keep the scope in time with the stars;).

If you don't have an RA drive, then it's more fiddly to use the RA circle... you need to adjust the RA circle to a known star immediately before using it to find or measure another object.

I hope this helps. Keep asking questions if it doesn't!:D

Al.

[alphamone]

kay, thanks.

[sheeny]

At the risk of providing "too much information";):)...

I forgot to mention:

The right ascension of the spot in the sky directly over head is given by the local sidereal time. On the left hand side of the IIS web page is a panel marked "Your Zones". You can customise this to display your local sidereal time (as well as any other time zones you want).

If you want a program to run on your laptop (if you have one) while you are away from a web connection then have a look here:

http://www.iceinspace.com.au/forum/showthread.php?t=11321&highlight=Als+clock&page=2

BTW you will find the positions of all the stars, planets and DSOs in catalogues and publications like Astronomy 2008.:thumbsup:

Al.

[alphamone]

well, i realy do suck at polar allignment, but I did find saturn, and I could clearly see its rings with a 4mm eyepiece.

[sheeny]

:lol: We all start out that way!

Saturn is good like that... there's little dobt when you find it.:thumbsup:;)

What scope and mount do you have BTW?

Al.

[alphamone]

a celestron astromaster 130EQ with a CG3 equatorial mount.

Also, it is a pity that while mars is visible at this time, it is quite far away and hard to see any details without a very large telescope. It also sucks that jupiter doesnt rise until around midnight.

[Jen]

:hi: Hi Alphamone hey check out Chris's post here he has just finally worked out how to do that too be warned it it is long :thumbsup: (:lol: lol sorry Chris:P)
im still trying to work it out :screwy::stupid: :whistle:
http://www.iceinspace.com.au/forum/showthread.php?t=29845
cheers