Off Balance…

Celestron 11″ CPC mounted on a Celestron Super Wedge. This picture has the lighter SBIG ST-402 CCD and 80 mm guidescope, but the scope is currently featuring an SBIG ST-8E CCD and no guide scope. The ST-8E has an internal guider. .

In confessions of an ignorant astronomer parts 1&2 I detailed the maladjusted gears, inadequate wedge and the fact that this Celestron 11″ CPC telescope just had not ever worked well. So far I have had the telescope since 2014 and it has only returned about 5 good runs and even then it did not image all night like it was supposed too. It hasn’t gotten any better this year!

So after thinking seriously about selling the thing, I finally did something desperate…read the directions! Starizona has a really good web page with lots of great tutorials. So I found one on balancing the scope on a fork mounted telescope. Duh, I had been doing it backward! You balance the scope first by loosening the DEC clutch on the fork mount, tilt it vertically, then move around an external weight until it balances correctly. Then you tilt it horizontally and re-balance the tube. On mine I had to take one further step. Loosen the RA clutch and move it side to side. I used a C clamp on the west side to balance that axis. Now you can move it side to side and up and down with both axis loosened with no issues. I had been trying for years to balance the horizontal axis first!

Old picture of the counterweight system. On the current configuration the weight is closer to the top of the tube than the bottom of the tube. Still I have found that this setup is cheap and works well.

So after 4 years of fiddling around with the drive adjustments and weights it took 5 minutes to do it right! Amazing what reading a tutorial can do! While doing some internet research some people have needed to add a weight on the top of the tube as well as adding the counterweight system to the bottom. When I added 2 large metal straps (like the one above that made the weight holder) on the top of the tube it balanced perfectly. The system for keeping those weights in place is very sophisticated…black electrical tape and a bungee cord! If it all works, like it is supposed to, then it will be time to do something more permanent.

So how does it work? I don’t know! It is clouding up…again! When I get a chance to try out the configuration I will post an update and some better pictures.

Starizona webpage: