COMA COMA COMA, oh how I hate COMA.  So, not being independently wealthy, I decided to try to correct the problem. I have identified two main aspects of my setup which were contributing to pulling the optics out of alignment and causing the COMA.

The are:

1.)    My Olympus Camera is fairly heavy, and as such when coupled with the thin gage stele of the optical tube, actually causes the tube to flex just enough, to pull things out of collimation, even though without the camera, it was perfectly collimated.

2.)    The other issue has to do with the fact that having only one set screw in the focuser causes any eye piece which is not exactly the same size as the inside diameter of the focuser tube, to get put at an angle, especially when the Camera is mounted via the T – adapter.

Here is what I did. –

     To address the bending and flexing of the optical tube I decided to reinforce it.  My first thought was a steel plate, but I wasn’t sure if I could bend it to the right  radius. My text thought was a steel tube that would slide over the focuser end of the telescope over the main tube. The problem with this idea was that this would add considerable weight to one end of the telescope, and finding a tube big enough to slide snuggly, but easily over the existing optical tube, proved problematic at best. Then my dad made a suggestion.  He informed me that they use nylon rods and bar stock for bearing and abrasion surfaces in the grain elevator shop where he works.  (They manufacture grain elevator equipment among other things.)    So he had them make for me a 4” long ½” thick, 6 3/16” inside dia. Nylon tube. It is both light and durable. In fact, it turned out that my optical tube was actually 6 ¼” outside dia., so I ended up having to file down the inside of the nylon tube to make it fit. It took 10 hours to file away a 1/16^th of an inch, (about 1 ½ mm).  Finally I got it to fit.  This is attached to the optical tube via three sheet metal screws plus the five machine screws for the guide scope mount and the focuser.   I  can now guarantee that if enough weight were to be mounted on the focuser, the scope would be more likely to tip over rather than bend or flex.

     To address the “sloppy” eyepiece issue, I drilled two additional holes in the focuser where the eye pieces go in and tapped them out and put in two set screws, for a total of three to lock the eye pieces and or T – Adapter into place.  Just for good measure I also drilled another hole in the focuser body for a focus lock screw.  ( No more camera turning the helical focuser as it goes around the sky.)

Unfortunately, since I finished the modifications, it has been cloudy every single night!  Hopefully soon I will be able to post the “first light” post modification test photos with some success.

My Telescope before the modifications

After the modifications - view 1

After the modifications - close up view - note the extra set screws in the focuser.

After the modifications - entire setup