PDA

View Full Version here: : GSO 12" - Bobs Knobs vs. Astronomy-Shoppe Knobs


DougAdams
11-03-2007, 11:20 AM
I ordered some "no-tool" collimation knobs/springs from Astronomy-Shoppe.com and installed them yesterday - very easy to do and the scope performed well last night. But.... :)

... these new knobs project around 1 inch below the base of the OTA (the old screws were recessed into the OTA. This means if I rest the OTA on the ground when relocating the scope, it is now resting on the knobs.

Question: is that likely to mess around with the mirror?

Another question: I thought I was getting the Bob's Knobs, with the colour coded knobs for collimation/lock knobs - but these look different from the ones on the Bob's Knobs website - does anyone know if Bob's have a flatter profile than the Astronomy-Shoppe ones? ie. would they sit snug up in the OTA?

Last one: these stronger springs.... do they make the need for the "lock screws" on the GSO redundant? I haven't bothered putting mine back in... they don't seem necessary.

astronut
11-03-2007, 11:41 AM
Doug,
Yes they are a different shape to Bob's, but are the same size and depth.
I rest my tube on these knobs when transporting, or moving around at home.
Unless you twist and turn the tube whilst on the ground (unlikely) the collimation will not be affected.
If you have the stronger springs, you can kiss the locking pins goodbye.
I've made these changes to my Lightbridge and the difference between original and modified is "lightyears better":D

iceman
11-03-2007, 07:33 PM
ditto all the John said :)

DougAdams
12-03-2007, 11:00 AM
Thanks chaps. I do like this scope. I was showing a friend Eta Carina the other night when I noticed a funny cigar shaped bubble around the star itself. First time I'd actually seen the Homunculus - couldn't get over how easy it was to spot.