LDN 158, 148, 152, 162, 163 - Ophiuchus
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CLICK ON IMAGE FOR FULL SIZE VIEW (3989x2988) Scope: Explore Scientific MN152 at f/4.8, Location: DAA Observatory, Shelter Valley, CA, 3 and 10 June 2021 Camera: ASI1600M (Astronomik Gen 2 LRGB Filters) Exposure:
Exposure: L - 64 x 4.5 minutes (gain-1700 1x1) , RGB - 20 each x 3 minutes
- (gain-139 1x1).
Processing: Data
Collection - Sequence Generator Pro (as FITs). Sub-frame calibration
- Pixinsight. Sub-frame registration and integration (Average combine - Winsorized Sigma
Clipping) - PixInsight. Mure Denoise - PixInsight. Non-linear stretching, normalization and
gradient removal - PixInsight. Generation of starless nebulosity image
(Luminance) - Star XTerrminator and Starnet2. Curves, Levels, RGB combine, Luminance
layering - PixInsight. Final finishing - Affinity Photo.
Photometric RGB calibration
- PixInsight. Annotation - PixInsight, Aladin (Simbad and NED), and Affinity
Photo. This image is a LRGB with luminance layering. The
monochrome starless was combined with a full monochrome image (two stops down in
stretch) to minimize star bloat (using pixel math). Image processed at
4656x3520 resolution. Final
Image size is approximately 3800x2850. North is up in this image. This
image captures several Dark Nebulae that are faintly discernable due to limited
star field and limited illumination of surrounding dust. The nebulae in this
image are LDN 148, 152, 158, 162, 163 as well as a few others from the Dobashi
and TGU catalogs. There is also a non-visible but IR detectable star 2MASS
j16465480-1358175. This star has a high proper motion of 4,979 mas/yr - this
compares with the highest proper motion known star (Barnard's Star) with a
proper motion of 10,393 mas/yr. There are few with proper motions higher than
2MASS j16465480-1358175. High proper motion stars are characteristically
relatively close (as an example, Barnard's Star is only about 6.8 light years
distant). This means that the dark nebula obscuring it in visible wavelengths
must be even closer. So this means the dust around the dark nebulae is
has few stars to illuminate it. So the low contrast between the dark
nebulae and the area around it make it hard to image in visible wavelengths.
There are also two background galaxies that are visible through some of the
light dust - LEDA 926417 and 2MASS j16480313-1414517. These objects,
information, and some of the brighter stars are identified in the annotated
image. Horizontal FOV is approximately 85 arc minutes. Full size
image scale is approximately 1.28 arcsec/pix.. Image center is approximately - Equatorial 2000: RA: 16h 48m 09s Dec: -14° 14' 36"
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