M31, Andromeda Galaxy

16 December, 2023
mono broadband galaxy

Acquisition Details

IC1848 L R G B
Frames 76 102 60 164
Exp. time 120s 120s 120s 120s
Flats 20 20 20 20
Darks Master      
Bias Master      

Final Masters



Normally, I am very critical of my work, but I am secretly quite proud of this result.

The weather is nothing but cloudy these days. Yesterday we’ve had one night of clear sky and M31 in Zenit. Guess what the target was…

This is my third attempt to capture M31, our closest neighboring galaxy. Its distance from us is “only” 2.5 million light years, which is relatively close in astronomical terms. Wanted to shoot H-alpha channel as well but trees were blocking the view by then. Might add those later.

M110, Andromeda’s satellite galaxy

M110 M110 Galaxy

Another thing to keep in mind during the processing of this image was to make sure enough details of M110 remained visible. As you look closer, some dust cloud are visible.

Astrometry Calibration

Astrometry Job 8927496
Center (RA, Dec) (10.716, 41.263)
Center (RA, hms) 00h 42m 51.856s
Center (Dec, dms) +41° 15’ 46.807”
Size 2.55 x 2.56 deg
Radius 1.807 deg
Pixel Scale 1.56 arcsec/pixel

Data Processing

Processing was done in PixInsight only. Steps of the process are listed below:

  1. DynamicBackgroundExtraction on separate channels,
  2. LRGBCombination on only RGB channels
  3. SPCC,
  4. SNCR noise reduction (0,70) to reduce green noise,
  5. ArcsinhStretch a couple of times to stretch the RGB image where colors remain having their calibrated color value,
  6. BlurXTerminator on the L-channel for correcting stars and nebulae
  7. LRGBCombination to merge the noise L-image on the RGB-image
  8. StarXTerminator (splitting stars and background),
  9. Color adjustments on the starless image
  10. NoiseXTerminator on the starless image using masks for separate background and galaxy noise reduction
  11. Merging of the stars and starless image using PixelMath, expression: $T + STARS
  12. DarkStructureEnhance on the image (0,40) to enhance galaxy dust bands
  13. Final adjustments with CurvesTransformation
  14. Last small bit of noise reduction using NoiseXTerminator
  15. Star reduction/resizing using the StarDe-emphasis script (add the url https://pixinsight-updates.astroswell.com/ to your repositories)