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How to use a collimation eyepeice?

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OK, got my collimation eyepeice thingy the other day (thanks Steve :D )

Had a wee go on Sunday at trying to line things up on my Lightbridge, but I'm a bit unsure

what I'm meant to do, or where to actually start. Theres also a hole

at the side, which Ive no idea what thats for...

Had a look on google, but things got way confusing... arrrggghhhhhh!!!!!!

Any help would be muchly appreciated

Cheers guys/gals :)

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Also worth noting that the Cheshire and a red-light torch can be used to test/set collimation in the dark.

This from the 'Schlatter Family Site':

Now, you are outside, it's dark, your eyes are dark-adapted, and you don't know if the scope is collimated properly. You know your secondary is in good shape because you adjusted it properly and it rarely needs further adjustment. You don't want to turn on a white light and fool around with the primary adjusting screws. This is where the Cheshire comes in.

Look at the Cheshire, the shiny, mirrored portion of the Cheshire is tilted at 45 degrees. Note that this shiny mirrored surface faces out of a hole in the side of the Cheshire. The bottom of the Cheshire is open just like the sight tube and the top has a tiny peephole. Note that the mirrored surface has a hole in it -- when you look through the peephole in the top, you look down through this hole and through the bottom of the Cheshire.

It's dark. You have your trusty red LED flashlight and your Cheshire. Scope is set up and you think the primary was knocked out of alignment when you bounced up the road. Insert the Cheshire into the eyepiece opening of the focuser so that the hole in the side of the Cheshire is aimed in the same direction as the scope. Shine your red LED light onto the mirrored surface and look through the peephole.

The red light from the LED flashlight bounces off the 45-degree surface, off the secondary, and onto the primary. By looking through the peephole, you see the primary glowing gently red, reflected in the secondary. In the center of the primary is the center spot and the peephole -- just like during the day when you collimated the scope. If the reflection of the primary is not centered in the secondary, or if the center dot is not centered, loosen the lock screws and adjust the primary. That's it.

The Cheshire allows you to collimate the primary mirror under dark conditions, using your red LED light as the light source.


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