A good clear night last night and I don't think I have imaged IC2169. This image was tough to process. Background extraction in SIRIL seemed to be introducing noise, so I tried processing with drizzle still no go. I then tried running the stacked image through BlurXterminator and NoiseXterminator prior to background extraction, then extracted background / gradient using GraXpert. But again it looked like the process added noise, so I ran the graXpert file through BlurXterminator and NoiseXterminator and the result was so much better. I did not introduce the final file formats to further processing in Affinity photo, this is all just SIRIL, with Generalized Hyperbolic Stretch Transformation, Histogram Transformation, and Color Saturation. I am happy with this result for it looks similar to the photo described in the below text.
IC2169 is a bright blue reflection nebula in the constellation of Monoceros about 2 deg west of the Cone Nebula and Christmas Tree Cluster. The smaller reflection nebula in the lower right corner of the image in NGC2245. These objects, along with the Cone Nebula, NGC 2264, are part of one large star-forming region, RSF3 Mon.
Dreyer's Nebula - IC447 (IC2169, LBN903), IC446 (IC2167, LBN898), NGC2245 (LBN904), NGC2247 (LBN901) in MonocerosNegev Desert, Israel
Total Exposure Time: 8:00 hours L(bin1); RGB(bin2),
LRGB 220:90:80:90 // 48 frames of 10 minutes each
RA 06h 33m 10s, Dec +10° 10' 00"
Pos Angle +00° 40', FL 599.6 mm
This image is 1600x1244 pixels
Officina Stellare Riccardi-Honders Veloce 200 RH OTA
Officina Stellare - http://www.officinastellare.com/products_scheda.php?idProd=15
On my site - http://www.pbase.com/boren/officina_stellare_riccardihonders_veloce_rh_200
Deeper technical informaiton on the Riccardi-Honders design - http://www.telescope-optics.net/honders_camera.htm
SBIG ST8300M, LRGB Astrodon Gen II filters
NEQ6 mount, guided w/PHD
IC 447/2169 is a reflection nebula but … it has an identity crisis. The NGC project - now back on line at a new URL, http://www.ngcicproject.org/, under new ownership but same content by Dr. Robert E. Erdmann, Jr. - has this to say about the nebula and the nearby reflection nebula (half degree north of it) reflection nebula (IC-446/IC-2167) I haven't as yet imaged. They, though, are connected by a dark nebula:
"The same two objects [IC-446/IC-2167, and IC-447/IC-2169] were apparently discovered twice by Barnard... Neither of Barnard's positions is particularly good, though we can get close to the apparent center of his large, diffused nebulosity if we adopt his RA for IC 447 and his Dec for IC 2169. Even though his two positions are more than 10 arcmin apart, they clearly refer to the same object: it is big (I make it about 30 x 30 arcmin on the DSS). Barnard notes "several stars 9-10 involved"; those stars are indeed there."
Barnard never realized they were the same object. Though in a later publication he did retract his discovery of IC 447 saying it was a duplicate of NGC 2245 -- the cone nebula. Which, of course is incorrect. He did though send the data on both to Dreyer who did publish it in his second IC catalog without apparent verification and likely accepted Barnard's description without viewing it himself. So even the most careful of visual astronomer's, and Barnard is considered one of the best, did make mistakes that the later photographic era would have prevented. Or maybe not considering the SH2-235 problems.
IC 447/2169 (it is also known as Dreyer's Nebula) is located in Monoceros, the unicorn. So obviously another that has been waiting on the hard drive for some time. It is thought to be part of the huge cloud of dust and gas that includes the far more famous emission and dark nebula known as the Cone Nebula as well as the Christmas Tree open star cluster and the Fox Fur Nebula. If so it is about 2700 light years distant, considerably further away than the nearby Orion Nebula complex.
Being a reflection nebula it is a blue color. The color comes from scattered star light of the illuminating stars which are either in or behind it. The nebula is blue for the same reason our sky is blue. The tiny molecules of dust and gas scatter blue light better than the other colors due to its short wavelength. It matters little what color the illuminating stars are, as long as they emit some blue light the nebula was take on a blue color same as the somewhat yellow sun still results in our blue sky. (ref.: http://cosmoquest.org/forum/showthread.php/89363-IC-447-2169-A-large-reflection-nebula)
@ Information from https://www.pbase.com/boren/image/148405510
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