Dec Setting

[Terry]

I am greatly confused. When I look at the Dec settings on my Explorer 130 the Dec scale goes from 90 at the 12 o'clock position to 0 at the 3 o'clock back to 90 at the 6 o'clock back through 0 at 9 o'clock and back to the 90. I have worked out that the 12-3 and 9-12 arcs are not the ones to set to but if a star has a Dec setting of say 45 degrees do I set it to the 3-6 or 6-9 45 degree position or dosen't matter.

Terry

[proflight2000]

Terry, an easy way to try this is to find a star, sat sirius or something, look up its RA and DEC is stellarum, or starry night etc, then set your circles to what it says, that may give you a better understanding. Once you have the RA and DEC for sirius, find a close star to it and turn the scope to it, look at the readings you get on your circles and compare them to the new RA and DEC of the new star, see if that may make it easier to figure what you have.

[Terry]

Thanks Proflight, I'll give that a go next time I get a clear sky. I think I have got my head round it a little more.

Terry

[timetraveller]

hiya Terry I have the bigger brother of your scope the p200 8" AP the DEC setting circles are the same on mine too and the simple answer to your question is very straight forward to understand bud you originally need to set the scope up for polar alignment ( pointing north ) once done viewing from north to east and some way beyond you would use 12-3 part of the setting circle, but when you try to point south through Southwest and to the west you will find the mount will have limited travel because of the RA motor cover which means at that point you will need to flip the ota through 90 degrees on the Ra axis which means the the other half of the setting circles will come into play for the DEC angle you will also need at that point to rotate your ota tube around in its mounting rings in order to regain the use of the focus mount

hope this explains it to you but proflights answer to you is equally valid you need to align the DEC 0 angle up using known star positions to

regards Pete

[TheThing]

Sorry to soud rude Pete, but you last post would benefit from some punctuation!

I know exactly what you're trying to say, and it is a great explanation, but it does get lost without commas and full stops!

No offence intended.

[Terry]

Many thanks Timetraveller

That has explained things perfectly.

Terry