Star Halo Control - How to?

[glend (Glen)]

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.

[gregbradley]

Can you post an example photo?

Greg.

[Shiraz (Ray)]

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

[glend (Glen)]

Originally Posted by Shiraz

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.
Thanks