Halos around M45 stars

[pi_co100]

This is a picture I have taken on Thursday night with a Takahashi FC-100DF at f4.9. 

It is an LRGB composition using 34 frames of 30 seconds exposure for each L R G and B. I have used an ASI1600MM-C with the 36mm ZWO filters. Considering that the supermarket in front of my garden did not switch off (not even at 2am!!) their vast array of blue, white and yellow halogen lights illuminating the car park and pointing up at the sky and towards my garden, perhaps I should not be too disappointed with the result. 

I would be interested to know if the halos around the stars are a function of the filters I have (these the standard ZWO set which I bought one year ago) or they are just unavoidable in the circumstances as the stars are too bright. Also the rays of light on the bright stars - are they artefacts of the filters that better filters would remove?

Higher resolution here:

https://www.astrobin.com/full/374969/0/?nc=pieroc

Thanks for feedback and comments!

Piero

 

[SteveA]

Not too disappointed!...your kidding of course..

That's really very very nice indeed

Steve

[Thalestris24]

Hi

I'm not sure - might you have had some dew? There is some slight egginess on the left hand side/bottom (in the full-size image) - may be camera tilt?

Louise

[pi_co100]

Thank you both! I will make sure the dewzapper is on next time and wait a bit longer before spending ££££s on some expensive filter....?

[Thalestris24]

9 hours ago, pi_co100 said:

Thank you both! I will make sure the dewzapper is on next time and wait a bit longer before spending ££££s on some expensive filter....?

It just came to mind that sometimes halos can be caused by a moist atmosphere or very high, thin clouds. Or even by problems with a filter or image processing. It's probably worth checking individual subs and the separate stacks to see if the halos are present/not present.

Louise

[Laurin Dave]

Hi,

Nice photo, I have the same camera and filters..  I think a few things are going on..  filter reflections (the concentric circles)..  ASI1600 microlensing (the square boxes) and maybe some water vapour/high cloud (was there a halo around the moon?).  Filters with better AR coatings would I guess reduce the filter halos but with the ASI1600 the microlens/diffraction effect may then become more apparent - I'd find this much more annoying than the halos. You get microlensing on bright stars with this camera, it is in my experience/with my equipment unavoidable.  You don't see it on your M101 image.

 

Dave