code - lucatironi Code snippets and tutorials

Messier 31

Andromeda Galaxy

Messier 31

click image to see full size (3008x3008px)

The Andromeda Galaxy, also known as Messier 31 is a barred spiral galaxy approximately 2.5 million light-years from Earth and the nearest large galaxy to our own Milky Way. Wikipedia


This is the first image I took with my rig after moving to the countryside and upgrading to the SkyWatcher EQ6R-Pro mount. Setting up the equipment, focusing and doing the polar aligment with the ASIAIR Pro was straightforward and didn’t take too long.

I then used the Go-To function from the Sky Atlas on the ASIAIR to slew and then frame the Andromeda Galaxy. It felt even too easy! I decided to take 5 minutes long exposures and at least 12 of them, for an hour of total integration.

Acquisition Details

Dates August 23rd, 2022 (Waning Crescent Moon)
Frames 12x300” (5mins), 1 hour of total integration time
Focal Length 360mm (f/6)
Camera ZWO ASI533MC-Pro (gain 100, cooled at 0°C)
Telescope TS-Optics Photoline 60mm Doublet Apochromatic Refractor
Accessories 1.0x Flattener
Filters TS-Optics 2” UV & IR Cut Filter
Mount Sky-Watcher EQ6R-Pro
Guide Scope Angeleyes Mini Guidescope 30mm f/4
Guide Camera ZWO ASI 120MM mini
Computer ZWO ASIAIR Pro

Processing Details

I stacked the ligths frames in Siril using the OSC Preprocessing Without DBF (Darks, Biases, Flats) script. I decided not to use any Dark, Bias or Flat frames. I might try to create a dark frame library later, but the ASI533MC-Pro is considered a camera that can do without darks given the absence of amp glow.

I then used the following tools:

  • Photometric Color Calibration
  • Asinh Transformation (stretch 768.2, black point 0.003)
  • Histogram Transformation (mid 0.341, low 0.013, high 1.000)
  • Saturation enhancement (amount 0.13)

Additional Images