Collimation: first experience with artificial star

Discussion of using SharpCap for Deep Sky Imaging
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psy1280
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Joined: Wed Oct 24, 2018 4:52 pm

Collimation: first experience with artificial star

#1

Post by psy1280 »

Last night was the first night I tried to use my Hubble Artificial Star. I used a Celestron SCT 8" with my ZWO294 camera connected directly to the OTA. Although I had success (see image), I'm wondering if this degree of collimation is adequate? Should I have used a 2x barlow between my camera and the OTA? Also, I wasn't able to create more deffraction rings, does that negate the collimation?

Much thanks,
Joe
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admin
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Re: Collimation: first experience with artificial star

#2

Post by admin »

Hi,

I thought the other pattern was supposed to appear as you moved closer to the focal point – you may need to remove choose the exposure or the brightness to avoid that being swamped out. I expect you have seen this page - http://www.astrophoto.fr/collim.html

By the way, you have a very rare image there – an image taken through an SCT with no sign of convection current effects!

Cheers, Robin
psy1280
Posts: 208
Joined: Wed Oct 24, 2018 4:52 pm

Re: Collimation: first experience with artificial star

#3

Post by psy1280 »

Thank you for that reference Robin, it really helped.

Joe
Kopa
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Joined: Wed Jul 08, 2020 6:26 pm

Re: Collimation: first experience with artificial star

#4

Post by Kopa »

I have also tried tried an artificial star collimation for the first time.

Unlike the proper round star above, I had simmering light from my artificial star in the garden. I had sort of concentric yellow and blue rings that swapped places as I moved from out of focus through focus and out of focus again.





As of now I don't know what to make of it and based on the attached images I don't know if I have managed to collimate my telescope successfully.
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Screenshot 2020-11Art Star3.png
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Screenshot 2020-11Art Star2.png
Screenshot 2020-11Art Star2.png (261.82 KiB) Viewed 1608 times
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