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Old 12-10-2016, 08:48 AM
glend (Glen)
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Star Halo Control - How to?

I must admit I have not paid much attention to the topic of star halos in capture and processing. However, now that I am imaging with refractors it is becoming a concern. What is the capture strategy to minimise halo, if any? I was running a sequence on the Horsehead/Flame area last night in narrowband and ran into significant Oiii large extended halo from Alnitak, with no such issues from Ha, and just a little from Sii (when preview stretched in SGP). I checked the objective just to make sure I was not seeing fogging, but it was completely clear. I have considered adjusting the camera (ASI1600) Gain downward for Oiii, or going to shorter subs and reshooting that filter. What should I be doing?

Equipment used was the TS Photoline 115mm/f7 APO running at f5.5 with (0,79X) reducer/corrector. ASI1600 gain settting at 139.

Last edited by glend; 12-10-2016 at 09:00 AM.
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Old 18-10-2016, 10:24 AM
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Can you post an example photo?

Greg.
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Old 18-10-2016, 08:42 PM
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Shiraz (Ray)
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might not even be a problem Glen? - Alnitak is an extreme blue star that has buckets of output in the blue compared to red. You should see a big extended blue halo around it with typical optics
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Old 18-10-2016, 09:40 PM
glend (Glen)
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Quote:
Originally Posted by Shiraz View Post
might not even be a problem Glen? - Alnitak is an extreme blue star that has buckets of output in the blue compared to red. You should see a big extended blue halo around it with typical optics
Thanks Ray, that is what i see and that explains the Oiii image.
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