Here’s update #2 for February 2010.

I had a chance during the day this Saturday (02/20/10) to do some more work on the project.  With my wife’s help, we carried the completed truss tube up to the garage, and bolted it to the mount.  I then rolled the big scope out of the garage for some adjustments and testing.

The last time we had the Byers mount out with a scope attached, both the RA and DEC drives were slipping.  I was able to correct the RA issue with a slip clutch adjustment.  To adjust the tension, I disengaged the worm, and adjusted the clutch until I could move the scope without slipping, by grabbing the worm wheel by hand.  I did the same adjustment with the DEC worm wheel.

The next task was to mount the secondary, do a rough collimation, and then check the back focus at the focuser.  As assembled, there was probably 2.5″ of back focus, so I adjusted the entire primary cell assembly back about 1.5″ and re-collimated (good thing I designed in this little feature).  I then popped in several eyepieces to see if I was able to obtain an infinity focus (while looking at trees in the distance) and they did.  I still need to do a careful collimation of the scope, and I may need to shift the focuser a bit, but so far so good.

I had to stop working on the scope in the late afternoon, so I couldn’t declare this as our “First Light” event, but just for mount testing, I did point the big scope at the Moon.  The RA drive and slow motion works great.  Tracking was good.  However when I tried the DEC slow motion, there was a problem.  It works, but only after a long wait for the gear play to be taken up.  It also had intermittent operation in one direction.

So, the conclusion I drew was that the current DEC motor is just too slow.  To fix this, I ordered another new DEC motor for the scope that turns at 3 times the rate.  Hopefully this new motor will arrive soon and I’m sure that with some additional adjustment and tinkering, this will put this scope in a fully operational status!

After I get the collimation fine tuned and after the DEC slow motion issue is resolved, we’ll have a “First Light” ceremony!

Dark skies,

Larry