A framing of some of the star clusters and nebulas in western Gemini and northern Orion, taken on a partly hazy night adding the star glows to accentutate their colours. At bottom is the nebula NGC 2174, the Monkey Head Nebula, over the border in Orion. At centre near the orange star Propus is the supernova remnant IC 443 in Gemini. The fainter diffuse nebula IC 444 is at left near the star Mu Geminorum, aka Tejat Posterior. The area around IC 444 contains the large star cluster Collinder 89. At top right is the large star cluster Messier 35 with its smaller companion cluster NGC 2158. The field is filled with bright but cool orange giants stars and hot blue stars. This is a stack of 9 x 5-minute exposures taken with the sky relatively free of clouds, blended with a stack of 6 x 5-minute exposures when the sky was hazy (but not too hazy!), to add the star glows. All with the SharpStar 61mm EDPH refractor with its flattener/reducer at f/4.5, and filter-modified (by AstroGear.net) Canon R camera at ISO 800. Autoguided and controlled with the ASIAir Mini, and on the Sky-Watcher Star Adventurer GTi small equatorial mount, taken as part of testing this combination of gear. The polar alignment was off slightly but at this scale didn't hurt each sub-frame much. But the field rotated slighly from frame to frame. Each frame was dithered (shifted a few pixels) by the ASIAir to eliminate thermal noise pixels when stacking the images. Taken from home March 15, 2023. Nebulosity brought out with luminosity masks created with Lumenzia, plus with a starless layer created with Star XTerminator, and with a layer created with the Nebula Filter action with PhotoKemi Actions. All stacking and blending in Photoshop.
A portrait of various emission nebulas in southern Gemini and into northern Orion. At top is the bright star cluster Messier 35, with the small more distant open star cluster NGC 2158 below and to the right of it. Left of centre is the shell-like supernova remnant, IC 443, aka the Jellyfish Nebula. The small blue reflection nebula above and to the left of it is IC 444 amid a field of fainter emission nebulosity. The round and bright nebula at bottom is IC 2174 in Orion, aka the Monkeyhead Nebula. It is mostly an emission nebula but has some blue reflection components. The smaller round red nebula above it is Sharpless 2-247. It appears to be an ionized HII region, as a form of bubble, but is not a planetary nebula. So this is a field of various forms of nebulas: emission, reflection and supernova remnants. Missing is an obvious planetary nebula or dark nebula. The orange star to the right of the Jellyfish is Propus, or eta Geminorum. This is a stack and blend of filtered and unfiltered exposures, the latter set maintaining the natural star colours, and avoiding the haloes introduced by the filters, particularly the L-eXtreme. The image is a blend of: 10 x 6 minutes at ISO 800 without a filter + 8 x 12 minutes at ISO 1600 with an Optolong L-eNhance dual narrow-band filter + 6 x 16 minutes at ISO 3200 with the Optolong L-eXtreme vary narrowband filter, the latter set taken at the end of the sequence when the field was quite low. Through masking the L-eXtreme images contributed only some of the nebulosity, particularly the subtle cyan fringes on the leading edges of IC 443 — it is the Oxygen III cyans that the L-eXtreme is good at picking up. All were with the Canon EOS Ra camera and through the SharpStar 76mm triplet apo refractor with the EDPH reducer/flattener for f/4.5. Guiding was with the multi-star Lacerta MGEN3 stand-alone auto-guider, which also controlled the camera shutter and performed dithering between each frame to shift each exposure by a few pixels for noise reduction in stacking. All stacking, alignment and blending was with Photoshop v22.3. Some curves were applied with Lumenzia luminosity masks to selectively adjust the mids or dark-mid tones. Nik Collection ColorEFX ProContrast filter applied locally to the nebulas, plus a high pass sharpening, both to further enhance the nebulosity. No darks or LENR frames were employed or applied on this cool but pleasant and very clear and dry late winter night.
A framing of a field in southwestern Gemini rich in star clusters and nebulas. At top right is the rich star cluster Messier 35 and its small more distant companion cluster NGC 2158. At bottom right is the emission nebula NGC 2174 that is over the border in northern Orion. Above centre is the supernova remnant IC 443 arcing to the east of the orange star Propus or Eta Geminorum. The large diffuse nebula at left is IC 444 above the orange star Tejat Posterior or Mu Geminorum. The large, loose cluster Colliner 89 is embedded in IC 444. That region also has some blue reflection nebulosity, as does NGC 2174. This is a combination of exposures taken without a nebula filter blended with exposures taken through an IDAS NB1 dual narrowband filter: 17 x 4 minutes unfiltered at ISO 800 blended with 10 x 6 minutes at ISO 3200 with the filter, all with filter-modified Canon EOS R, on the SharpStar 61mm EDPH at f/4.5, on the Sky-Watcher EQM35 mount autoguided with the ASIAir Mini computer. The Mini performed dithering moves between each exposure to reduce thermal noise hot pixels. The Images were shot over two nights: filtered on March 19 and unfiltered on March 21, as this area of sky was in the southwest and not high enough for more than 1 to 2 hours of shooting. Plus some ice fog and frost intervened. Taken as part of testing this combination of gear as an entry-level setup. Stacking, aligning and processing in Photoshop, using luminosty masks, a starless layer and the nebula filter action in Photokemi actions to bring out the faint nebulosity.
