Image of the day

From the
ATWB Customer Gallery

Lightning #1

My Account

New to Astromart?

Register an account...

Need Help?

Finished refurbishing a starliner, now what?

Started by keithjg, 12/27/2012 03:10PM
Posted 12/27/2012 03:10PM Opening Post
Three years after rescuing this scope from a dirt floor garage, where it was frozen into the floor, I have finished restoring it. This is a 10 " f/5.5 on a 1.5" shaft starliner mount. The original secondary had fallen off the spider and hit the center of the primary. The secondary had broken in half, and the primary had a nice scuff right in the center (luckily). The coatings were all but gone anyway. I sent the mirror off for an enhanced aluminum coating, and last week finally ordered a 1/20th 2.14 quartz secondary from ProtoStar. One of the tube rings was snapped, and I had that re-welded, straightened out the bent spider, replaced the starting capacitor on the RA ac motor- etc. The meade 80mm f/15 came with it, along with a unitron spotting scope.

I have never set up or used a reflector.

Today I installed the primary and secondary, and started to align everything. The Mirror is not centered in the tube quite perfectly. I have no centermark on the mirror either. I used an orion laser collimator to adjust everything so that the laser fires in the focuser, hits the secondary, primary, secondary again then back up to the collimator.

Is that the correct way to align it? I was reading a lot about having a secondary offset, and light cone positioning- what should I do next? how much does the centering of the primary cell matter? I pointed the thing out the window at a transformer about 500 yards away, and even through our snowstorm here in the northeast, I was able to very clearly read the small labels. What should I do next? I figure I have at least a week now before any clear skies!

Regards,
Keith G
Wolfeboro NH

Attached Image:

keithjg's attachment for post 56973
Posted 02/16/2013 07:04AM | Edited 04/23/2013 12:03PM #1
Keith,

Looks like you did a nice job with the telescope resoration. Are you going to repaint the mount once you've got everything working correctly?

I'm not a really experienced Newtonian user but, as to your question about collimation: The first thing to do is make sure the secondary is centered over the primary. There is "word" out there that there should be some offset (I think toward the focuser" for the secondary. I think it's Suiter that recommends it in his book. I've never tried it, though. Then I insert my laser into the focuser. I tip and tilt the secondary until the laser hits the center of the primary mirror. I know you just got your mirror back, but perhaps the firm that coated it could also have applied a center spot. I think there are forum posts here for applying a center spot yourself. Then work with the primary to make the laser beam shoot back through the collimator and hit its center mark.

I think things are easier overall if the primary is centered in the OTA, but I don't think it's required. I think the main thing is to have the secondary centered over the primary.