Fear of Mirrors II: When Mirrors Attack

The weather was still horrible right up until this evening so I finally decided to have a go at center-spotting the mirror with a ring-binder reinforcement ring. I carefully made my template. I cut out a circle in the middle of it that was just the right size for the reinforcement ring to pass through. I cleared a workarea in the kitchen and laid everything out.

On the advice of someone else I even went to the trouble of marking up each of the screws and their position on the 'scope so that I could put everything back where I found it.

Then I picked up the screwdriver.

I started to undo the first screw. With just a handful of turns it become really loose but didn't seem to want to come out. Few more turns, still loose, but not coming out. I found this odd, considered giving up there and then and then decided to tighten it up again just to check that I wasn't doing anything stupid. It tightened up fine. So, I started to undo it again and, after a lot of turns it finally came out.

Started on the second screw. Same "loose but not coming out" thing was happening. So, wanting to be sure I still wasn't doing something stupid, I did it up, popped the end off the scope and shined a light down it to see what was happening.


At the bottom of the scope was a nut just lying there doing nothing useful! It was then that I realised that I was undoing totally the wrong screws. There are four screws around the outside of the bottom of the 'scope and I'd got it into my head that it was those that I should be undoing. Wrong screws! I should have been undoing the three locking screws on the bottom of the 'scope.

After a few moments of bad language and resisting the urge to bang my head against the nearest wall I wandered off to have a small break and calm down.

I then carefully tilt the 'scope up and let the screw run out into my hand.

So, next, I undo the right screws and out pops the mirror with no fuss or bother at all. I fix the wrong screw back in place and then offer the template up to the mirror. Thankfully it seemed to be a perfect fit. The problem now was that my hands were shaking so much that I couldn't get it fully in position and wouldn't have got the reinforcement ring in place no matter how hard I tried.

Another break.

This time I manage to get the template over the mirror with little fuss and drop the ring into position. After measuring it looks like I've probably managed to get it between 1 and 2mm off center but I'm assured that this shouldn't really matter too much.

After putting the 'scope back together (thankfully a reasonably hassle-free procedure) I found that the alignment of the optics was totally off so I'm then forced to do my first ever round of collimation. Now I see why so many people (myself included) are put off doing it. I undid the locking screws and then started to mess with the adjustment screws to see what effect they'd have and started to get a feel for it pretty quickly. Once I was happy that everything was roughly lined up I did the locking screws up again and this threw it right out again. So, what followed was a period of messing with locking screws and adjustment screws until I finally had everything locked into place and pretty well lined up.

So, as best as I can tell at the moment, I'm now back with a working telescope that's about has badly collimated as it was before — perhaps slightly better — but with a center-spot to help with using a laser collimator and also that helps with collimating by eye. And, of course, I'm also left with an experience that sort of confirms that my fear of going near a telescope with a screwdriver wasn't that irrational after all.

To top it all off, when I stuck my head outside about half an hour ago, the rain had stopped and the clouds had cleared and it looks like it's heading for a nice clear night. I can't decide at the moment if I should drag the 'scope out and see if it still actually works or if I should just sit in a chair and try and catch some late Persieds.

Still, it seems like it's been a useful night after all. Lessons have been learnt and experience gained.

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