Confessions of an Ignorant Astronomer…

Since tomorrow starts the busiest week of the year for me I packed up last night and went in at 11:30 after the scope lost alignment for the 2nd time. Functioning on 4 hours of sleep the night before as well as a high dose of Predinsone for heat induced asthma issues did not help the motivation factor. The 11″ or Temple 28 just would not work! A 4 mph wind came up and started blowing it all over the place so thought I was still dealing with balance issues. I had hoped the ST-8 camera with it’s internal guiding chip would solve the issues that I was having with a heavy external auto-guider. When that still didn’t work I gave up and went to bed!

When the 11′ was purchased I was assured that the mount had been worked on (hypertuned) but that it all needed more work and was unfinished. That is definitely true, everything is well lubed, clean and polished internally but still needed a lot of wiring and work. I had noticed while loading it in my car, that when you bumped the scope you could hear the worm gears skitter over the main gears. Not being familiar with this type of telescope (Celestron CPC) I had no idea that this was not normal and was just a balance/design issue with these scopes in general. The CPC were primarily for visual use and I was hanging lots of heavy cameras and stuff off of it so expected some problems. I had also heard that the tension spring was not very robust and that was a flaw of the CPC series. So over the years I added weight and contraptions to try and get better balance so it would not get bumped or blown and lose alignment. Some of the time it worked some of the time it didn’t. 

When I woke up this morning the decision was made that I needed to do some work related chores today and not mess with telescopes. So I got a home office wifi issue solved so I could work at home easier and decided to get busy on my office work. Only to realize I had forgotten to post the file where I could access it at home. Sooo…just couldn’t resist thinking about this problem and decided to do a little research on the CPC instead. After looking at other peoples issues It struck me that the problem seemed like a tensioner on the drive motors needed adjustment. Outside it was 105 heat index but I just had to know if that was causing the issue. After pulling off 5 cover screws and looking at the tensioner the adjustment screw was practically falling out and the tension on the worm was almost nonexistent! In fact the nut that keeps it all tight and adjusted was completely away from where it needed to be. So even if it had been adjusted once,  it would not stay that way very long, especially after 3 moves in 1 year! Three minutes later…problem solved, at least on one axis. After the scope was put back together, cranked it through from side to side several times and it worked without a hitch! In fact it sounds smooth and has no slippage even if you put a little pressure on the fork. In all of the trouble shooting articles read today the importance of listening for gear noise, chatter or sounds of strain were emphasized as part of diagnosis and adjustment. 

Now the adjustment is not really why I am so dumb and mad at myself…it is because I have had this telescope for three years and didn’t figure it out until now! When you have slipping gears it is no wonder it is hard to internal guide, external guide, balance or anything else! One or two images would look good then 2 bad would follow with no rhythm or reason. Drives you nuts! When I was researching the issue this morning I saw a guy in England that had an CPC with an oversize finder, 102 mm triplet telescope attached, 2 cameras plus the main 8″ scope. I was having trouble with just a camera and OTA! That’s when I knew I was a total moron! His issue was the nylon clutch but in the course of replacing the clutch there was a description of how to adjust the tension. In fact, to make it worse, I know how my LX200 looks internally with a similar design and it has no slippage issues at all! So why didn’t I think there was something wrong with the RA gear from day one? 

However, there are two axis on a scope. So after 1 hour, 20 dollars in tools, contortions to take off 6 torx screws to get to the drive unit and a bit of dehydration, (real temp 104 and “feels like temp 117”) the declination is now adjusted as well. So now I am all set to have a productive night tonight…Not. Severe thunderstorm warning until 1 AM and cloudy all week.

Trying out a new semi-permanent station for the telescopes. Trailer screw cemented into the ground then straps and and metal cable to hold it down against the wind. Thunderstorm in 2 hours so it is a proof of concept night. The left scope is the AR102, and Sirius mount covered by an actual insulated telescope cover. The scope on the right is wrapped in a waterproof tarp covered by an heavy duty weather resistant canvas tarp. It is all bungeed down tight to the trailer screw. Hopefully, things will stay tied down and will not pop up in another blog entitled…”Stupid!”