I imaged this way back in January, right after I got my first actual telescope. From then till this month I've been reading, experimenting, and learning how to use PixInsight (while working on other targets). M42, despite being a "bright beginner target," is remarkably difficult to process!
Working on this data I went through too many iterations to count. This is the version I'm finally happy with despite the visible noise due to short integration (fog rolled in and cut my night short out in the Everglades). Comments/critique welcome!
Total integration: 1 hour 34.5 minutes (94.5 minutes)
179 x 30 seconds ISO800
30 x 10 seconds ISO800 (for the core)
Camera: Canon T3i (stock)
Telescope: Explore Scientific ED80 f/6.0 Apochromatic Refractor (with ES field flattener)
Mount: Orion Sirius EQ-G (unguided)
Bortle Class 3 (Burns Lake Campground in Big Cypress National Preserve near Ochopee, FL)
Stacked with PixInsight, processed with PixInsight, GIMP, and Paint.NET