Avoiding burnt out hilights?

[FLO]

When imaging the likes of M31 Andromeda Galaxy and M42 Orion Nebula, with bright cores.

How do you prevent the cores from blowing out?

I guess it's in the stacking?

[GordonCopestake]

i think a lot of people use composites. I keep meaning to investigate HDR photography as there seems to be some use in astrophotography

[Jamie]

Hi Steve there are 3 main ways to avoid centre burnout.

1 Take short exposures and stack them on top of the burnt out version.

2 Take short exposures as before stack them then crop and paste the central part onto the burnt out image.

3 Ask Rog.

[FLO]

Duly noted, thanks chaps

[CELESCOPE]

Much the same as has been said there really , m42 best done short exposure for the core, and a longer one for the outer regions , use layers i n Ps to combine the images , there is a process on the net have to find it and post it , for m31 much the same can be done , but the core can be improved by ditigal process in Maxim, using filters and establishing the cut off point in that area, when done a small gaussian blur softens the core, takes a while to master it ,

for ppl starting off imaging M31 , maybe the combined image would be better to start with .

Rog

[FLO]

Thanks Rog

[Caz]

If you find after you have taken all of the precautions to not burn the core of M31, a neat trick is too use the Shadows and Highlights feature in PS this will allow you too remove a lot of the burning out at the core. If you can get composite images right then it's a much better way it has to be said.

[russ]

Good idea to take images at various exposures. Some to capture the core, others to get the fainter detail.

Russ

[FLO]

Thanks chaps/chappess

[MartinB]

Here's a link - Jerry shows 2 ways to go about it.

http://www.astropix.com/HTML/J_DIGIT/COMP2.HTM

http://www.astropix.com/HTML/J_DIGIT/LAYMASK.HTM