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Collimation help

ChrisR36

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daz

daz

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Chris came over this morning, and Kai and I had a good look at Chris's scope...

Collimation was actually not a million miles out, but was tweaked and is (if I may say) as good as it was going to get in daytime.

The cell is bolted to the OTA, and the three wingnuts are indeed the collimation screws. There are no clips on the mirror, so there must be some sort adhesive arrangement on the mirror. The wingnuts work perfectly well, and collimation was straight forward.

The secondary is a solid design, the centre bolt being another wingnut, and the collimation screws being big slot screws. Much easier than fiddling with little allen keys!

The focuser is an Irving - solid, well made, very smooth r+p, 1.25" fit - which threw out the opportunity to use my Cats Eyes tools!

Kai and I got on with the business of collimation - as I said, not far out so didn't take long to do. Then onto the business of not achieving focus....

We focused on some distant hills and were perplexed when we confirmed what Chris had said - it needed almost a fully racked out focuser, and an extension tube in order to reach focus.

We then started thinking that the mirror had been moved, but we couldn't see that there would be enough travel on the collimation screws to move the mirror that far....

Time for tea....

Then Kai spotted it.... On the drawtube is a knurled ring, with the eyepiece locking screw. Kai says "Knurled knobs mean knobs that can turn" - so he did.... And there is an extension tube within the draw tube! We extended this out, removed the extension tube that we had put in and bingo!

The extension tube has a tight enough fit to not slip while in use, but closer inspection showed there was another clamp in use at somepoint, to hold the extension tube in place.

Chris couldn't honestly remember seeing another clamp, but will have a look to see if he has one - if not then something like a small jubilee clamp will suffice (Chris, put some felt around the focuser to protect it if you do this!)

So, 30 minutes after arriving, Chris now has a collimated scope, that he can now reach focus with :)

Thanks to Kai for playing host, and for spotting the trick with the draw tube, and to Chris for coming over to us :(

Now, let's see the observing reports!!

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ChrisR36

ChrisR36

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Thanks again Daz and Kai. I can't tell you how grateful I am. Top job!!

The sky's not looking very promising in Exmouth right now, but I'm itching to get out and start seeing stuff again, so I hope it clears up before nightfall.

I must get myself one of those collimating lasers like yours, and then I can keep on top of the fine adjustments every month or so.

Thanks again, it was good to meet you both, and hopefully I'll be back with some observing reports :)

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