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Mirror Lock and Collimation?

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4 replies to this topic

#1 PRejto

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Posted 31 January 2013 - 03:11 PM

Hello,
I'm new to CAT type scopes...I was testing my Meade 12" ACF with a camera for the first time last night. After getting near focus with the built in focuser I finished up focus with the Feather Touch focuser I have on the back. I took a few star field photos that I observed in CCDInspector and was quite pleased to have a flatter field than I expected (17% KAF8300), and quite good collimation. I then realized that I had not locked the mirror. After locking, and after refocusing, my results were appreciably worse....poor collimation and poor curve results 30-40%. I did not expect this kind of result, but perhaps this is normal behavior. I ran out of time/energy to attempt physical scope collimation after locking. Is this normal?

Thanks,
Peter

#2 Christopher Erickson

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Posted 31 January 2013 - 09:09 PM

Check your collimation with the mirror lock off and again with the mirror lock on.

#3 PRejto

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Posted 31 January 2013 - 10:26 PM

Check your collimation with the mirror lock off and again with the mirror lock on.


Thanks! Sure...I plan to do this. What I'm wondering is what other people observe. Do you see any change in collimation with the mirror lock on or off?

Peter

#4 Christopher Erickson

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Posted 01 February 2013 - 12:05 AM

Check your collimation with the mirror lock off and again with the mirror lock on.


Thanks! Sure...I plan to do this. What I'm wondering is what other people observe. Do you see any change in collimation with the mirror lock on or off?

Peter


It would be normal to experience a small amount of change in collimation and pointing. However a whole-bunch of difference wouldn't be normal.

#5 Markigno

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Posted 01 February 2013 - 07:12 AM

What I'm wondering is what other people observe. Do you see any change in collimation with the mirror lock on or off?

Peter

No, the collimation is affected in very small part, or for nothing, after mirror lockup.
Marco


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