Collimating screws......

[karateman]

Anyone know what size the collimating screws are in a 1999 Celestron Celestar C8. I think they will be imperial as opposed to metric. I want to change them for equivalent thumb screws which should make it easier to collimate. I know you can get some from Bobs Knobs, but they are about £15 inc postage for 3.

Phil

[karateman]

Anyone know what size the collimating screws are in a 1999 Celestron Celestar C8. I think they will be imperial as opposed to metric. I want to change them for equivalent thumb screws which should make it easier to collimate. I know you can get some from Bobs Knobs, but they are about £15 inc postage for 3.

Phil

Anyone please?
Phil

[RickJ]

Take one out and measure it. Nothing will fall apart. You have to do that when you replace them anyway.

Rick

[karateman]

Take one out and measure it. Nothing will fall apart. You have to do that when you replace them anyway.

Rick

Thanks Rick, it did cross my mind but had visions of something dropping off..lol

Phil

[RickJ]

I should add I was talking C8 when I said nothing dire would happen. With some Meade SCTs you must tighten the other two screws before removing one or the spring might push the secondary so far from the plate you can't reach it with a correct length screw.

This brings up another point. When buying a screw be sure you don't get one longer than the one in there, even 1 mm longer (newer C8's are metric) than the factory one. If it is longer it can break the seal between the secondary and its mounting plate as it will push against the mirror when too long. Also keep the scope pointed at least a few degrees down when removing a screw. Just a safety precaution.

Rick