Orpington Astronomical Society

Astronomy => Technical => Topic started by: Les on Jul 17, 2011, 17:31:30

Title: Help needed
Post by: Les on Jul 17, 2011, 17:31:30
Last night was one of the few nights I've been able to take the telescope out and I noticed that the focus is still off. Instead of a pinpoint star, what I saw was like a ring. With the telescope I only got one eyepiece - a 26mm QX. The scope has a 254mm apeture, a focal length of 1270mm and a focal ratio of f/5.

I thought I had it sorted when I turned it on the moon a few backs, but seems as though I didn't. Can anyone offer advice or help?

Les

Title: Re: Help needed
Post by: Rocket Pooch on Jul 17, 2011, 18:53:22
Les,

If you have a barlow put that in and see if you can get focus, if you can then the scope / focuser does not have enough in-focus.

Whats is the is the scope and setup, i.e. diagonals etc?

Chris
Title: Re: Help needed
Post by: mickw on Jul 17, 2011, 21:04:13
I think you said it's a 10" Lightbridge.
Was it new ?

If you haven't got a Barlow (a tube that magnifies the eyepiece) you could try getting the thing as close to focus as you can then loosen the eyepiece and gently ease it in or out of the focuser to see if that improves matters.
Title: Re: Help needed
Post by: Les on Jul 18, 2011, 15:28:08
The telescope is brand new but didnt come with a Barlow. In a few weeks, I should be getting an eyepiece set which does include one. If it helps then I could just go for the cheaper eyepiece set without one and get the Barlow now.
Title: Re: Help needed
Post by: mickw on Jul 18, 2011, 15:55:21
Stick to the better eyepieces and try moving the eyepiece as I said earlier.

Has it ever managed to get in focus or is this the first time you've tried it - Might be worth speaking to the supplier, it could be damaged
Title: Re: Help needed
Post by: Les on Jul 18, 2011, 17:31:35
I'm positive that it was ok when focusing on the moon - but that was done @ about 1am sio maybe I was wrong about that. Will try adjustments on the next clear night.