Orion Nebula HDR Exposure Question

[John K]

Hi guys,

At the end of the month, I would like to shoot my first HDR image of M42 with my 12.5" f/5 and modified Canon 400D.

Based on having Orion at least 30 degrees above the horizon and getting close to 3 hours of data on a single night, my plan was to shoot to following exposures, stack them separately in Deep Sky Stacker, and then combine them using the HDR feature in Photoshop CS3.

Planned exposures:

10 x 15 seconds - 2.5 mins
10 x 30 seconds - 5.0 mins
10 x 60 seconds - 10 mins
10 x 120 seconds - 20 mins
10 x 240 seconds - 40 mins
10 x 480 seconds - 80 mins

All of these would be shot at ISO800.

Just wondering what everyone thinks of the plan - too many steps? not enough exposure? ISO too high/low?

Any advise that people have would be appreciated.

Clear skies,
John K.

p.s. If I have posted this question in the wrong section happy to move it!

[Amaranthus (Barry)]

I really think this is overkill - you really only need two - a shorter exposure length for the core (Trapezium zone), and a long exposure for the surrounds.

At f/5, I would advise 15-20 sec subs for the core, and 300-600 sec for the rest. ISO800 sounds good.