M31: Capturing the Andromeda Galaxy with a Smartphone and Tracker

Prepare to be amazed by what's possible with today's technology! We're diving into an astrophotography project that pushes the boundaries of what we thought a smartphone could achieve. This incredible shot of the Andromeda Galaxy (M31) was captured entirely on a smartphone, proving that you don't always need a dedicated astronomical camera to reach for the stars.

The Gear: More Than Just a Phone

At the heart of this operation is the Xiaomi 13 Ultra, specifically its impressive 5x built-in periscope telephoto lens. This isn't your average pocket-sized camera; it's a testament to the advancements in mobile optics.

But even the best smartphone needs a steady hand – or in this case, a steady mount. This setup utilized an EQ mount with OnStep, a crucial piece of equipment for tracking celestial objects accurately over long exposure periods. Without this, even the slightest movement would result in blurry images.

The Process: Data Acquisition

Capturing deep-sky objects like Andromeda requires patience and a significant amount of data. Here's a breakdown of the imaging sessions:

• Session 1 (2025.06.07):
  • ISO: 3200
  • Exposure: 30 seconds
  • Lights: 150 frames (RAW/DNG)
  • Includes dark frames and bias frames for calibration.
• Session 2 (2025.06.21):
  • ISO: 3200
  • Exposure: 30 seconds
  • Lights: 123 frames (RAW/DNG)
  • Includes dark frames and bias frames for calibration.

This resulted in a total integration time of 2 hours, 16 minutes, and 30 seconds. The moon was unfortunately quite bright during these sessions (89%), which adds an extra challenge, but the results speak for themselves.

The Magic of Stacking and Processing

Raw data from multiple frames needs to be meticulously processed to reveal the hidden details of celestial objects. This project employed a robust workflow:

• Stacking: The raw frames were stacked using Astro Pixel Processor (APP), with a 2x drizzle applied. Drizzling is a technique that increases the effective resolution of the final image, bringing out finer details.
• Processing: The stacked image was then refined using a combination of powerful software: GraXpert, Siril, and Adobe Camera RAW. This multi-stage processing is key to bringing out the faint structures of M31 while managing noise and maximizing dynamic range.

The Result: A Galactic Masterpiece

This image is nothing short of astonishing. The detail visible in the spiral arms of the Andromeda Galaxy, captured by a device that fits in your pocket, is a testament to how far astrophotography – and smartphone technology – has come. It's truly remarkable to think that such a distant and magnificent object can be observed and recorded with such clarity using this setup.

It's inspiring to see such incredible effort lead to such breathtaking results. This project serves as a powerful reminder that the universe is accessible to all of us, even with the tools we carry every day.