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Collimation - which screws are which?

Parallax

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Parallax

Parallax

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I'm going to have a go at collimating the Explorer 200. No, that's not quite correct. I started to collimate, got confused and have now probably messed it up all together.

The manual says that the Phillips screws are for adjusting and the Allen screws for locking. I've just been looking at web site where the chap explains collimating the same scope and he says the reverse of the manual.

Has anyone had experience of collimating this scope and can confirm which screws are which, please?

Steve

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John

John

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On the Explorer 200 that I had the larger diameter phillips-type screws were the actual collimating screws and the smaller, recessed allen key ones were the locking ones. My routine was to slacken the locking screws 1st, then make any adjustments needed to the primary mirror tilt using the collimating screws, then re-tighten the locking screws.

John

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Posted
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Another excelent post.

The Skywatcher looks exactly the same as my Celestron C8N.

Now i know what the little screw holes were/locking screws.

Just as well i read this before colminating my main mirror as i did not have a clue about locking screws.

Recently bought a Badder colminator from Flo, it may be too accurate with my C8N eyepiece as last night i was looking at Saturn through a 2x Celestron Barlow and a 7mm Badder Orthoscopic eyepiece and when i tried using the focusing wheel the image moved through movement in my eyepiece.

Just experimeting with my Barlow, made everything go all fuzzy.

Thanks again.

Davey.

:moon:

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Whippy

Whippy

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Another excelent post.

The Skywatcher looks exactly the same as my Celestron C8N.

Now i know what the little screw holes were/locking screws.

Just as well i read this before colminating my main mirror as i did not have a clue about locking screws.

Recently bought a Badder colminator from Flo, it may be too accurate with my C8N eyepiece as last night i was looking at Saturn through a 2x Celestron Barlow and a 7mm Badder Orthoscopic eyepiece and when i tried using the focusing wheel the image moved through movement in my eyepiece.

Just experimeting with my Barlow, msde everything go all fuzzy.

Thanks again.

Davey.

:moon:

Davey, if the object you're observing moves while you're focusing, that means you have a focuser with image shift. It's got nothing to do with collimation (my C8N does exactly the same!). What I find with mine is use the laser to get your collimation close, then do a star test to get it spot on.

Tony..

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Thank you Tony.

You lot do not waste any time in replying to post.

I am a newbie and just getting the hang of the scope.

This week i have had 3-4 clear skies which is a blinkin miracle for up here in bonnie Scotland and i may go out for a look at the moon later on.

So now i need to learn how to do a star test, thanks for that.

Davey.

:moon:

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Parallax

Parallax

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Just to let you know how I got on.

I did a star test and it wasn't as far out as I thought it might be. I slackened the locking screws (Allen) and tweaked an adjusting scew (Phillips) to see which way, and which one, made it better/worse. It only took a few minutes and it is much better now BUT...

...Whislt I was removing the mirror cover plate it slipped from my (gloved) fingers and landed, edge on, right on to my webcam. The adapter went shooting off along the patio. Luckily it doesn't seem to have caused too much damage although the adapter thread is a bit chewed up. It still screws on OK but at an angle. I'll sort it out tomorrow. Hey, ho!

Steve

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The Warthog

The Warthog

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Another excelent post.

The Skywatcher looks exactly the same as my Celestron C8N.

Now i know what the little screw holes were/locking screws.

Just as well i read this before colminating my main mirror as i did not have a clue about locking screws.

Recently bought a Badder colminator from Flo, it may be too accurate with my C8N eyepiece as last night i was looking at Saturn through a 2x Celestron Barlow and a 7mm Badder Orthoscopic eyepiece and when i tried using the focusing wheel the image moved through movement in my eyepiece.

Just experimeting with my Barlow, made everything go all fuzzy.

Thanks again.

Davey.

:moon:

If your C8N is like my C6N, it is using a different system from the Explorer. The Exporer, like the Meade 4.5" I had, is using a locking screw and a collimating screw that pulls against the push of a spring. The C6N uses a push-pull system that is a PITA to collimate at first. One screw pushes the mirror forward, and the other in the pair pulls it back. If you want to push the mirror forward, you have to loosen the pull screw and tighten the push screw, which will push the mirror forward until the pull screw is flush with its hole. Opposite procedure for pulling the mirror backwards. The secondary is even more fun. Once you get used to it, it works. I did think about installing springs in the pull screws, and using the push screws as locking screws.

One word to the wise - on the Explorer, don't tighten the locking screws much. You may throw your collimation out, so just make them 'finger-tight.'

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