2019-12-18: ET TU, BATES?

I use my C8 Edge scope on an equatorial mount or my Celestron Evolution mount at least every first Saturday of the month for a public star party. During the December party the secondary had a meltdown and it took quite a while to get the collimation back to where everything didn't look like a comet. It had always been pretty good abput staying aligned until then.

While getting the collimation reset I suspected, and it turned out, that the quality of the secondary aparatus was as good as that of my C11 Edge secondary. Just three screws and that's about it. I ordered a set of Bob's Knobs, since the C8 is short enough to be able to look through the scope and adjust the collimation at the same time. I made the familiar trip to the hardware store and came back with a couple springs and a set of nylon washers.

Above you can see where the nylon washes went. I don't like metal to rub on metal unless it is necessary. The scotch tape helped me keep nine things in place with only two hands.

I snipped off three pieces of spring from the large one that were about the length of the exposed threads. The platform for the secondary mirror is nearly parallel to the platform for the whole secondary when the collimation is close, so I wanted the springs to be compressed a little when the two were parallel, but still allow a bit more compression as needed to get the alignment correct. The point of the springs were to always keep a little tension on the threads of the knobs to keep them from turning by themselves.

Done. The three springs could have been a bit closer to all being the same length, but it should be OK. Now I can continue to sleep at night.

THE END

2019-04-08