The nebula complex lies on the border between constellations Orion and Gemini and is a part of the GEM OB1 molecular cloud. Further details can found below the image.
Click on the images for a full scale version.
This image is a false color composite where [SII] is mapped to red, H-alpha is mapped to green and [OIII] is mapped to blue. Stars are partially subtracted using continuum images.
The three larger nebulae are (from right to left) SH2-254, SH2-257 and SH2-255. The smaller nebula below SH2-254 and SH2-257 is SH2-256. SH2-258 is the small reflection nebula on the left side which appears magenta (due to the color factors).
The distance of the ionizing sources of the emission nebulae can be queried from the Gaia DR3 database:
Nebula
Source
Distance in light years
SH2-254
HD 253247
6500 ly (± 300 ly)
SH2-255
LS 19
6700 ly (± 400 ly)
SH2-256
2MASS J06123651+1756548
6150 ly (± 200 ly)
SH2-257
HD 253327
5150 ly (+5000/-2000 ly)
In the image SH2-254 seems to lie behind SH2-257.
Image data
FOV:
0.47° × 0.33° (full view)
Date:
2019-2021
Location:
Pulsnitz, Germany
Instrument:
400mm Newton at f=1520mm
Camera Sensor:
Panasonic MN34230
Orientation:
North is up (approximately)
Scale:
0.8 arcsec/pixel (at full resolution)
Total exposure times:
H-alpha (3nm):
8.0 h
[OIII] (3nm):
14.1 h
[SII] (3nm):
10.9 h
NIR:
0.6 h
Blue:
0.7 h
Image processing
All image processing steps are deterministic, i.e. there was no manual retouching or any other kind of non-reproducible adjustment. The software which was used can be downloaded here.
Image processing steps where:
Bias correction, photon counting
Dark current subtraction, flatfield correction, noise estimation
Alignment and brightness calibration using stars from reference image
Stacking with masking unlikely values and background correction
Extracting stars from the emission line images using information from continuum images
Denoising and deconvolution both components (stars and residual)
RGB-composition
Dynamic range compression using non-linear high-pass filter
Tonal curve correction
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