Capturing Andromeda Without a Tracker: A Taste of the Cosmos from Poland

Andromeda Galaxy

Greetings, fellow stargazers! Today, we're diving into the celestial wonders of the Andromeda Galaxy, also known as M31. What makes this particular capture special is that it was achieved without a tracking mount – a feat that presents a unique set of challenges and rewards.

The Target: M31 and Its Companions

The Andromeda Galaxy is our closest spiral galaxy neighbor, located approximately 2.537 million light-years away. In this image, we can also spot its two satellite galaxies: M32, a compact elliptical galaxy, and M110, an irregular dwarf galaxy. Seeing these galactic entities in a single frame is always a breathtaking experience.

The Challenge: Going Untracked

Astrophotography typically relies on equatorial mounts that precisely track the apparent motion of celestial objects across the sky, counteracting Earth's rotation. Without tracking, stars appear to trail as the Earth moves during the exposure. This means shorter exposure times are crucial to freeze the stars, but this, in turn, requires stacking more images to build up enough signal for a detailed shot.

The Setup and Acquisition Details:

Camera & Lens: 70mm focal length with an APS-C crop sensor.
Aperture: f/4
Exposure: 3.2 seconds per frame
ISO: 1600
Lights: 900 frames captured (600 frames were ultimately used after calibration).
Calibration Frames: 80 Darks, 100 Bias frames.
Total Integration Time: 30 minutes

The Processing Pipeline:

Stacking: DeepSkyStacker was employed to align and stack the captured frames, combining the faint light from M31 while reducing noise.
Processing: SIRIL was used for the main image processing, bringing out the details and colors.
Background Extraction: GraXpert was utilized for effective background correction and removal of light pollution gradients.

The Location: Dark Skies of Tatra National Park

This image was taken in the pristine dark skies of Tatra National Park, Poland. The Bortle scale reading of 4 indicates a relatively dark site, minimizing light pollution and allowing fainter celestial objects to be observed and captured. Despite the moon being at 91% luminosity, the dark sky site still provided a good base for this challenging shoot.

A Testament to Persistence

Photographing deep-sky objects like M31 without tracking is a testament to patience and meticulous processing. Each of the 600 frames needed careful alignment and stacking to create this final image. The result is a rewarding glimpse into the vastness of our universe, even from our own planet's surface.

Clear skies!