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  #81  
Old 09-11-2018, 09:24 PM
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multiweb (Marc)
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Final cassegrain collimation tonight looks good.



Done with a ZWO ASI 120MM. THis time on the mount so it was very easy to recenter after tweaking the secondary tilt.
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  #82  
Old 10-11-2018, 09:17 AM
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Kinda looks like a telescope again
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  #83  
Old 10-11-2018, 10:31 AM
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Great work on the collimation Marc. Looking forward to the images to come.
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  #84  
Old 10-11-2018, 04:26 PM
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Quote:
Originally Posted by LewisM View Post
Kinda looks like a telescope again
I knew frankenstein always had it in him, under all that rust, dints and cr4p it was a diamond in the rough.

Quote:
Originally Posted by Kunama View Post
Great work on the collimation Marc. Looking forward to the images to come.
I received all the collimation kits and adapter this morning in the mail so I will revisit for sure. The scope is cooling outside as we speak, everything is set up for a night of imaging or two, as sunday is looking good too..
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Last edited by multiweb; 10-11-2018 at 06:30 PM.
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  #85  
Old 11-11-2018, 12:55 AM
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Tonight's efforts.

NGC104 8x180s
NGC2070 29x120s

Need to still fix collimation for stars. I can do that tomorrow as I've received all the collimations kits this morning. Field looks sharp and flat though with no noticable curvature or flaring corner to corner.
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  #86  
Old 11-11-2018, 04:15 PM
Dennis
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Quote:
Originally Posted by multiweb View Post
Tonight's efforts.

NGC104 8x180s
NGC2070 29x120s

Need to still fix collimation for stars. I can do that tomorrow as I've received all the collimations kits this morning. Field looks sharp and flat though with no noticable curvature or flaring corner to corner.
Yes Marc - they look very good from edge-to-edge, very nice indeed.

Cheers

Dennis
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  #87  
Old 11-11-2018, 07:33 PM
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Quote:
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Yes Marc - they look very good from edge-to-edge, very nice indeed.

Cheers

Dennis
Looks a lot better than the mewlon 210 because it's a classical cassegrain and better corrected. It was fairly easy to collimate accurately today. The newtonian side I did struggle. Got it in the end but it was pretty hard.
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  #88  
Old 11-11-2018, 08:14 PM
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Looks like a great project Marc. Can't wait to see some images.

ps - no sign of Indian Mynas on those antennas....
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  #89  
Old 12-11-2018, 06:42 AM
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Quote:
Originally Posted by peter_4059 View Post
Looks like a great project Marc. Can't wait to see some images.

ps - no sign of Indian Mynas on those antennas....
I've had one dropping on the white tube already. No respect...
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  #90  
Old 12-11-2018, 07:05 AM
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Test images look good, Marc!
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  #91  
Old 12-11-2018, 11:34 AM
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Test images look good, Marc!
Getting very close now.
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  #92  
Old 12-11-2018, 01:46 PM
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I've had one dropping on the white tube already. No respect...
White?! White?! It’s not bloody white. I wish it were white... bloody ochre with blue tint...

Oh I had fun with that tube... might send Arief a “Pain and Suffering” claim (joking...kinda)
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  #93  
Old 12-11-2018, 07:01 PM
Dennis
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Hi Marc

I don't know where I obtained this "Collimation Guide" but here it is, if it can be of any use for the CN-212.

Cheers

Dennis

EDIT:
http://www.alluna-optics.com/Downloa...on-English.pdf

https://gravitylens.files.wordpress....collimator.pdf

Last edited by Dennis; 12-11-2018 at 07:14 PM.
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  #94  
Old 12-11-2018, 07:35 PM
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Thanks a lot for posting all the links Dennis.

Quote:
Originally Posted by Dennis View Post
Hi Marc

I don't know where I obtained this "Collimation Guide" but here it is, if it can be of any use for the CN-212.

Cheers

Dennis

EDIT:
http://www.alluna-optics.com/Downloa...on-English.pdf

https://gravitylens.files.wordpress....collimator.pdf
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  #95  
Old 12-11-2018, 07:35 PM
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Some moonage waiting for dark tonight. SONY NEX-5 at the cassegrain focus in live view. With Mynas and all...





Video at cassegrain focus [F/12.4]



Video at newtonian focus [F/3.9]



Some stacked stills from the ASI120MM. All cassegrain. First one is at the newtonian focus.
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Last edited by multiweb; 13-11-2018 at 08:53 AM.
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  #96  
Old 13-11-2018, 07:11 AM
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Last night was great for testing. I had a couple of hours before clouds rolled in from the west and there was also a thin moon crescent to play with.

I had used the TAK scope the previous day to finish collimating the cassegrain focus. It's very close but still needs a tiny more tweaking which I'll do with the artificial star. I spent some time on the moon visually from 32mm to 24, 9, 6 and 4mm eyepiece. I could still easily snap to focus with the 4mm eyepiece and see some very nice sharp details. A lot more than with the C11. I took a couple of shots with my SONY NEX-5 and ZWO ASI 120MM.

Then I switched to the newtonian side which was a bit of a disaster. Visually the focus point snaps and the image is very sharp as well. The fov is huge. On closer inspection at higher magnification I can see very obvious astigmatism so the detective work is starting. I suspect something to do with the secondary as the primary is ok in cassegrain mode. There is an aluminum cylinder that encases the secondary glass to stop it from dewing up I assume. It was very tight so I've losen that. I think maybe it was pressing against the glass. The astigmatism can be compounded by the fact I still haven't got the newtonian side collimated correctly. But there is definitely some kind of stress in the glass there.

Here' s a couple of shots of the primary collimation push/pull system, centering and locking mechanism. It's well designed and very simple.
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  #97  
Old 13-11-2018, 10:08 PM
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Some good progress. Finally got everything collimated tonight including the newtonian side. The aluminum shroud for the secondary was stressing the glass and causing the distortion. Losening the screw that holds it did the trick. There is a very slight sign of astigmatism when very close to focus but nowhere near what it was. I don't think it will be and issue with the CCD given the image scale as it is so close to focus, might not even notice it. Will see when I do a full fov shot. I also tested the newtonian corrector. Seems to do a decent job. Will post before/after pics later on.

This is the diffraction rings for the newtonian focus IN/OUT. First part of the video with the SONY NEX-5 , second with the 120MM.

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  #98  
Old 13-11-2018, 10:30 PM
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Here's the uncorrected (1st) and corrected field (2nd) with the SONY NEX-5.
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  #99  
Old Yesterday, 08:50 PM
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I did a star test on both cassegrain and newtonian focus tonight taking advantage of the steady skies. Went down to a 4mm eyepiece and I didn't have to tweak either. Spent a bit of time on the moon, saturn, NGC 104, the tarantula, anything bright enough that I could see from my light polluted skies. So I think I'm done and dusted now. As Diego would say, I am happy.

Video of the moon tonight with the SONY NEX-5 at the Newtonian focus. No corrector.

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  #100  
Old Yesterday, 09:31 PM
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Woohoo!
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