M42 star halo

[MattJenko]

I posted this in Deep Sky, so apologies for double post, but think this is more suitable a place to ask about how to manage or deal better with a bright star with a monster halo. Earl  mentioned there might be reflections in the image train, but I don't know how to go about testing that out. I took some shorter exposure to help me get detail in the core for this - would it make sense to use this to try and somehow process the star in a similar blended way?

[ollypenrice]

The mid ranges of brightness in this image are remarkably good. Well done.

Here's the thing about problem stars; what would you like? Probably you'd like the background around those stars to be just background, halo free, and at the brightness of the background outside any scatter or halo that you have. And you'd like the star itself to be small and colourful and round. So...

Start with the linear image and experiment with curve shapes and stretches to see what curve has what effect. This kind of curve can be very good for controlling manic stars;

The best advice I can give is to play with curves, fixing points on the curves with 'pins' and bending the curve above and below them to see what happens.

When you have something you like for a problem star you can apply it to the final image via layers. It is far easier for me to demo this than it is to explain it, alas...

Olly

[Physicist13]

Lovely image!!! I always that the images are for oneself primarily so whatever you are happy with. Personally I wouldnt worry about the star..its just wht refractors show. But if you want to reduce the halo and star size then do as Olly says if you use PS. there are star halo reducing routines and star size reducing routines in PixInsight (s/w specifically designed for AP!). Yes you could mask things off and sub in short exp for the stars are these will be unsaturated and show less halo (they look saturated in the image posted). Or mask off the stars and surrounding and apply different stretches.

Patrick

[MattJenko]

Many thanks, both for the praise and the advice. This is all still very new to me, so learning each and every time I do anything!

Here is a revised version in which I have attempted what you suggest in terms of levels/curves for the errant star. I also managed to do a better job of blending a shorter exposure for the Trapezium. Amazing what a bit of sleep can do for one's processing skills and grasp of the logic of what is being done! I hope I have still managed to keep the feel of the original though, which I really liked.

[Qualia]

Gorgeous image, Matt. Absolutely inspiring. Thank you

[jtlandreneau]

what a great picture! your nebulosity is super crisp... how long where your shots? what ISO?

[MattJenko]

Thanks - My exposure times were 13 x 600secs for this with a few 1 minute subs for the core. I used an ISO setting of 400. I have subsequently reprocessed to get the core less blown out, but also lost a bit of control over my halos as a result. I have worked out that these are actually reflections in the DSLR itself, so I have some work to do to deal with that in future. It amazes me how different processing can make such a difference. Always more to learn and do!!!