A framing of the area in Gemini containing the large and bright star cluster Messier (M) 35 at right and the curving Jellyfish Nebula, aka IC 443, at left, near the star Propus or eta Geminorum. The small but rich star cluster below M35 is NGC 2158 . The blue reflection nebula above the Jellyfish is IC 444. The Jellyfish is a supernova remnant some 1500 light years away and about 21 light years across. This is a stack of 6 x 8-minute exposures and 8 x 4-minute exposures, all at ISO 800 with the Canon EOS Ra red-sensitive camera, and through the SharpStar 94mm apo refractor at f/4.5 with the EDPH field flattener/reducer. The later shorter exposures were shot with the field getting low in the west and into the murk and light pollution on an early April evening. I shot these as part of testing the new SharpStar 94mm EDPH refractor. No nebula filter was employed here. Luminosity masks with Lumenzia applied as well as a layer of contrast boost applied to the nebulas using the Pro Contrast filter in the Nik Collection Color EFX Pro set of filters. All stacking and blending was with Photoshop. No dark frames taken or applied, just dithering applied between exposures to shift each image by 5 pixels. Auto-guiding, camera control and dithering were with the Lacerta MGEN3 stand-alone auto-guider.
The Jellyfish Nebula, IC 443, at left near the star Eta Geminorum at left. IC 443 is a supernova remnant. At upper ight is the bright open star cluster Messier 35. The smaller and fainter star cluster below M35 is NGC 2158. M35 is 2500 light years away but NGC 2158 is 16,500 light years away. This is a stack of 10 x 6-minute exposures with the 92mm TMB apo refractor at f4/4 with the Borg 0.85x field flattener/reducer and the filter modified Canon 5D MkII at ISO 800. Taken from New Mexico.
The area of sky around the star cluster Messier 35, at top in Gemini, with the supernova remnant IC 443 below, and the Monkeyhead Nebula, IC 2174, in Orion at bottom. This is with the 200mm Canon lens to frame a binocular field of view, and taken with the filter-modified Canon 5D MkII camera at ISO 800, for a stack of 9 x 2-minute exposures and through the NISI Natural Night filter to help bring out the nebulas. On the iOptron Sky Guider Pro. Taken from home Feb 20, 2020. The modified camera did a better job at recording the red nebulas than the stock 6D MkII did in shots taken the night before for comparison.