https://allans-stuff.com/2011/12/20/m42-the-orion-nebula-revisited/ Wed, 19 Nov 2025 13:38:40 +0000 hourly 1 https://allans-stuff.com/2011/12/20/m42-the-orion-nebula-revisited/#comment-31124 Wed, 19 Nov 2025 13:38:40 +0000 http://blog.allans-stuff.com/2012/08/04/m42-the-orion-nebula-revisited/#comment-31124 Hi
I’m new in the business. Ijust shot m42 using: samsung S21 ultra with 25mm Eyepiece on celestron 4se (4″, 1325 mm focus), alt-az tracking (technical reasons), no filter, in 8-9 Bortle area. I’ve shot 210 lights, 30 darks and 30 biases with 4sec and 3200 ISO.
Next I stacked in Siril and streched in Graxpert. Only 13 out of 210 lights were stacked due to poor conditions. I write you because my m42 image is very like your original image- same “seahorse” and ngc 1977 on the left.
You wrote about second image:
“In this one image are stacks of 5 second, 10 second, 15 seconds, 30 seconds, 45 seconds, 60 seconds, 120 seconds and finally 180 seconds images. Each stack is then combined using HDR Efex pro to create the composite and then stretched in Photoshop. That’s 90 lights, 20 darks and 20 bias”. So there are 8 sets of lights, but only 20 darks and biases.
As far as I understand each set has to be with its own sets of calibration frames. And why you didn’t shot flats?
Please advise
Thank you in advance
Dimitri

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