MFO- 002, Messier 31 - Andromeda Galaxy

Tom Shankapotomous
Oct 31
3 min read

Target: Messier 31 (Andromeda Galaxy)

Date: 12 November 2025

Location: Johnson Family Farm Area, Newberry, South Carolina

Instrument: ZWO Seestar S50

Exposure: 10-second subs, automatic stack

Filters: IR-Cut

Processing: None — unprocessed live-stack

Observation Summary

This field session captured the central disk and dust-lane structure of the Andromeda Galaxy (M31) using the Seestar S50 under Newberry’s mid-November sky. The image above represents the raw, unprocessed stack—exactly as collected in the field with no external calibration or post-processing. Despite minimal setup and a Bortle ~5.5 sky, the Seestar pulled out surprising clarity in the inner disk.

The bright, condensed bulge of M31 dominates the center of the frame, surrounded by its characteristic tilted spiral disk. Two major dust lanes are visible, even without processing, running obliquely across the galactic plane. Numerous foreground Milky Way stars scatter across the field.

This observation serves as a reference point for future stacked, calibrated, and APP/Siril-processed versions.

Sky & Conditions

Sky Quality: Bortle ~5.5 (Newberry)

Transparency: Moderate

Seeing: Average

Moon: Not obstructive

Weather: Cool, clear November conditions with stable air layers

Despite the semi-rural light dome from Newberry proper, the Seestar’s auto-stack produced a stable and well-resolved core.

Target Notes

M31 — The Andromeda Galaxy
A barred spiral galaxy located ~2.54 million light-years away
Closest major galaxy to the Milky Way
Diameter ~220,000 light-years
Contains roughly one trillion stars
Approaching the Milky Way at ~110 km/s
At the time this light left Andromeda (~2.54 Ma), the Carolinas were in the early Pleistocene. The land around modern Newberry was already ancient, deeply weathered Piedmont crust undergoing climate-driven cycles of erosion long after the last mountain-building event.

Image Features (Unprocessed Interpretation)

Even without stretching or gradient removal, the following structures are clearly visible:
Bright galactic bulge:
A near-circular luminous core indicating the central star population.
Primary dust lane:
Seen as a darker, mottled band sweeping diagonally across the frame—evidence of cold gas and interstellar dust.
Secondary dust features:
Fainter but still traceable, especially on the lower left quadrant.
Outer disk glow:
A gentle falloff in brightness revealing the tilt of the galaxy relative to our line of sight.
Foreground stars:
Milky Way stars sprinkled throughout, helping frame the galaxy’s orientation.
This is a solid baseline capture for a field session with no manual intervention.

Equipment Performance

Seestar S50 Observations:
Alignment was smooth and accurate.
Star tracking held well through the stack.
IR-cut filter produced clean star profiles.
The auto-stack did not blow out the galactic core as severely as expected given the exposure time.
This reinforces the S50’s ability to produce publication-quality base images even under mid-range skies.

Next Steps for Processing

Recommended workflow for the next pass:
Export individual FITS files from Seestar.
Import into APP for gradient reduction and background calibration.
Stack using normalization + light pollution removal.
Move to Siril for curves and color correction.
Final pass in GIMP or Darktable for noise reduction and highlight control.
This image is an excellent candidate for a deeper APP re-stack, especially to reveal the faint outer halo of M31.

Field Notes (SGO)

Second Mobile Field Office capture process for data capture is doable while traveling for races.
No tripod instability.
No wind impact on tracking.
Object framed as intended—central bulge slightly offset gives better dust-lane visibility.
Test point for “raw vs processed” comparisons in future SGO entries.