R.A and Dec. circles on EQ2 mount

[ApprenticeAstronomer]

Hi all,

I've been reading that R.A and Dec. circles are pretty much useless on small mounts? Can anyone tell me if this is the case for the mount supplied with a Skywatcher explorer 130m?

Thanks in Advance

[themos]

Sadly, it is the case.

[phw26]

Hi all,

I've been reading that R.A and Dec. circles are pretty much useless on small mounts? Can anyone tell me if this is the case for the mount supplied with a Skywatcher explorer 130m?

Thanks in Advance

I still sometimes use my EQ2 mount, i have never tried to use them, I just star hop instead

[ApprenticeAstronomer]

I have been using it to star hop, however I really wanted to use it as it was meant to used. Disappointed! Serve's me right for rushing into purchasing a scope. On the plus side I'll get to learn the sky without relying on co-ordinates I guess.

[Bizibilder]

It is far easier to "star-hop" with a small scope. The problem with small setting circles is that you can only "set" them to about + or - two degrees (maybe a bit better with experience) but the field of view of the scope is only about one degree or less with the lowest power eyepiece - so the chances of lining up are not too good! You must also have your mount accurately polar aligned - any error will not help when using the circles (it may add to it!). Its easier to simply star hop around the sky. You will soon learn your way around.

You could try a Telrad (or other, similar) type of finder - these project rings against the sky to help with the star-hopping method of finding objects.

[ApprenticeAstronomer]

Do you still have to polar align?

[Skybrowser]

Polar align - yes, but approximate will do for visual. The setting circles are virtually for decoration I'm afraid.

[ApprenticeAstronomer]

Thanks guys for your help. For future reference, when purchasing another mount how can I tell if the R.A and Dec. circles will work properly?

[Bizibilder]

Unfortunately none of the RA and dec circles on the general run of the mill mounts are really any good. You really need a circle at least 8inches (200mm) in diameter that is precisely made (ie engineered not printed on) to be any real use. The trouble is that the manufactures want to sell you a goto mount (or upgrade) rather than the circles.

To be honest it would cost a lot of money to manufacture good circles - quite possibly the "computer" approach is actually cheaper to mass produce.

[ApprenticeAstronomer]

Goto mounts seem to take away the fun. I like the idea of learning the sky and reading star maps etc. Am guessing that most amateur astronomers use the star hop method?

[JamesM]

There has been plenty of 'discussion' on the virtues or as some have argued, the curse of the Goto system. Goto is very useful, but it can be undermined by the aperture of the scope that is used with it, if it is not capable of resolving what the Goto mount has found for it. If you prefer the traditional star hop method that's great, though I would reinforce Roger's (bizibilder) recommendation of the Telrad or other red dot finder (RDF) as this can make that process so much quicker.

As a footnote, I use a Goto system and for me it has also taught me the sky. I enjoy starmaps as well and use to them me make a selection for the night's viewing. Although my mount makes the occasional noise, it's not half as much noise as my fellow dobsonian observers make when they protest about my whizzing round the sky!:D

Clear skies

James

[skfboiler]

I'm the opposite. I find star hopping frustrating and I'm getting pretty good at finding objects with the setting circles. The key is getting precison alignment with a mount with a polar alignment scope. After you have found the object, whether star hopping or using the setting circles, the RA tracking is better when you a have a good alignment.