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Edge HD 11 Collimation

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#1 Cooksterman

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Posted 18 January 2020 - 06:38 PM

Is it possible to obtain precision collimation, with my Edge HD 11, with a cmos color camera or best practice to use a quality lens. I could experiment but thought expertise the better course for learning.

Thank you

Edited by Cooksterman, 18 January 2020 - 06:40 PM.


#2 barrett_flansburg

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Posted 18 January 2020 - 09:47 PM

I would recommend that you use MetaGuide with your ASI290 monochrome guide camera because of its small pixels. MetaGuide will show you a magnified view of a collimation star stacked to reduce the effects of seeing. By following the recommended collimation changes you will be able to improve the collimation until you can see the first diffraction ring around the Airy disk, which is about as good as you can get. MetaGuide is a free download from http://www.astrogeek...liss/MetaGuide/ and the author Frank freestar8n is active here on CloudyNights. There are videos on YouTube showing its use. 
 



#3 Cooksterman

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Posted 18 January 2020 - 10:14 PM

Thanks so much for direfcting me to MetaGuide.  I''ve reviewed the information on the site and am curious as to how it would differ from SharpCap as an example.  I apprecciate you directing me to MeaGuide and the YouTubes.   Here in Kentuckyana the seeing has been hampered with wetness and winds of late.  When the sky clear I'll be trying it out.

 

Clear skies

 

Barry...as well....



#4 barrett_flansburg

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Posted 18 January 2020 - 10:41 PM

I haven’t used the collimation tool in SharpCap, but it appears to try to map the variation in star image eccentricity using many stars in an extended exposure over the entire camera field of view (https://docs.sharpca...Collimation.htm). MetaGuide, by contrast, uses a single bright star at the center of the field imaged using short exposures to freeze the seeing. So MetaGuide is doing what you would do visually with a high power eyepiece, but it can do it better by stacking many short exposures to average out the effects of seeing. So, they are two different approaches. SharpCap gives you information about the entire field of view while MetaGuide lets you optimize collimation at the field center. 
 

I would try optimizing the field center with MetaGuide first, then use SharpCap to evaluate the stars in the field corners. If the stars in the corners are not symmetric, it may be that you need to adjust the camera tilt rather than the telescope collimation. 
 



#5 Cooksterman

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Posted 19 January 2020 - 06:50 PM

Makes total sense now that I understand the difference between the two.  Thanks also for sharing the discrete uniqueness of each of these two tools and how I might utilize them.  Due to the weather issues here I think it wise to utilize an artaficial star to collemate with MetaGuide to gain knowledge then when clear sky's present themselves again I will re-evaluate with the Rigal or such and then utilize Sharpcap for my final evaluation.

 

I appreciate your insights.  



#6 Endymion

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Posted 20 January 2020 - 07:52 PM

I believe Metaguide can also guide on the star you are observing to recenter it as you are adjusting the collimatation which is very useful.


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