EAA with 2x2 binning

Tonight, I took advantage of the clear skies despite a bright 93% moon rising at 8 PM. By the time I began setting up at 9 PM, the moon was already visible over the eastern hills. My goal for the evening was to revisit some of my previous targets, but this time using 2x2 binning and no focal reducer. This setup provides a resolution of 1 arcsecond per pixel instead of my usual 0.75 arcseconds. Given the city’s seeing conditions, this should be sufficient.

Setup and Initial Challenges

I started the session with calibration frames but wasted some time due to forgetting to set the binning to 2x2. When binning, I noticed a significant number of dead pixels in the dark frames and an abundance of dust donuts in the flats. I realized I should have cleaned the L-Enhance filter beforehand.

Due to Orion’s position in the sky and its imminent disappearance behind my house, I opted to skip my usual step of aligning the platform with the northern meridian using plate solving. 

Live Stacking and Initial Results

Similar to my last experience with binning, I observed that the live stacking process rarely rejected any frames. The live stacks appeared decent, potentially even better than my previous session, showing faint details more clearly. However, once I ran my Siril script to generate the final stacked image, I noticed that many of the details seemed washed out.

Manual Post-Processing Plans

One of my secondary objectives for the evening was to experiment with manual post-processing using GIMP or similar tools. I had tried this with some of my previous images and achieved promising results. 

I finally got to work on all the images on 3/4. 

  • I used StarNet++ through Siril to create a starless image and a star mask.
  • I denoised the starless image with GrapXpert.
  • I recombined the images after some level adjustments with Gimp.

Observations

  • M42 - Great Orion Nebula & M43 - De Mairan’s Nebula (Orion)

  • NGC 2024 - Flame Nebula (Orion)

  • IC 434 - Horsehead Nebula (Orion)

  • C50 - Rosette Nebula (Monoceros)

  • NGC 2264 - Cone Nebula (Monoceros)

  • IC 443 - Jellyfish Nebula (Gemini)

  • NGC 2174 - Monkey Head Nebula (Orion)

  • IC 2177 - Seagull Nebula (Canis Major)

  • Finally the Moon with FireCapture followed by ASIVideoStack


Images (from stackfit.js)


M42 Orion nebula and M43 de Mairan's nebula - 45x5s

NGC 2024 Flame Nebula - 21x5s

IC 434 Horsehead - 21x5s

C50 Rosette nebula - 22x5s

NGC 2264 Cone nebula - 36x5s

NGC 2174 Monkeyhead nebula - 23x5s

IC 443 Jellyfish - 21x5s

IC 2177 Seagull nebula - 32x5s

Moon - 50% of 217 frames x 4 ms

Images (processed with StarNet++, GraXpert and Gimp)










To be able to tell real details from de-noising artifacts, I uploaded one of the picture nova.astrometry.net (see here), which gives you a link to World Wide Telescope after plate solving. There you can cross-fade your image against the digitized sky survey.