With an apparent magnitude of 8.4, Messier 51 is a popular target for amateur astronomers and can be observed with a moderate-sized telescope under dark-sky conditions. Its unique appearance and scientific significance make it one of the most iconic galaxies in the universe.

With a fair amount of effort, I have made the raw data from my observation of Messier 51 available for download. I observed Messier 51, using my Stellina telescope and have painstakingly created a large ZIP file that contains the following files:

  1. All light FITS files; over 600-10 second exposures.
  2. Dark files; use these to calibrate the raw data files.
  3. TIF file from the telescope; this is the automatically-stacked, linear file that Stellina produces.
  4. Stacked FITS file; I stacked the 600 frames and dark files using Siril to produce this data-reduced, linear FITS file ready for further processing.
  5. Processed FITS file; I processed this file into its non-linear state to give you an idea of what’s possible with this data.
  6. Processed JPG file; this is the processed image in JPG format, ready for sharing.

Using the Dark Frames

Dark frames play a crucial role in calibrating the raw data captured during astrophotography. These frames are taken with the same exposure settings as the light frames, but with the telescope’s aperture covered to prevent any light from reaching the sensor. The purpose of dark frames is to capture the thermal noise and hot pixels generated by the camera sensor during the exposure.

By subtracting the dark frames from the light frames, you can effectively remove the thermal noise and hot pixels, resulting in a cleaner and more accurate representation of the celestial object being imaged. This calibration process is essential for achieving high-quality final images, as it helps to eliminate unwanted artifacts and improves the signal-to-noise ratio.

Without proper calibration using dark frames, the final image may suffer from increased noise, reduced dynamic range, and the presence of distracting hot pixels. By taking the time to capture and apply dark frames during the image processing workflow, astrophotographers can significantly enhance the quality and scientific value of their images.

Downloading and Processing the Observation Data

You can stack and process the files in this ZIP file using Siril, PixInsight, or any other software that’s capable of stacking and calibrating FITS files. Since processing can take a long time, I included the stacked, data-reduced FITS file that’s ready for additional processing – you’ll have to perform functions like gradient correction (background extraction), contrast adjustments, and cleansing of the final image to produce a nice-looking result. I also included a completely processed, non-linear FITS file to give you an idea of what you can do with this data, along with a processed JPG file.

The ZIP file is over 5.5 Gb in size, so it is hosted on my DropBox – just click the link and then select Download to download the file:

Download from DropBox (5.5 Gb)

Refer to the ReadMe.txt file in the ZIP archive if you have any questions, or contact me.

Observing and Sharing Your Data

Observing and capturing images of deep-sky objects like Messier 51 is an incredibly rewarding experience. By sharing the data and processed images, we can contribute to the collective knowledge and inspire others to explore the wonders of the universe.

I’d like you to try similar observations and share your data with the community. Collaborating and learning from one another can lead to discoveries and insights into the fascinating world of galaxies, nebulae, and star clusters.

Regardless of the equipment and observing conditions, your observations and data have value. By making your raw data available, you enable others to learn from your experiences, try different processing techniques, and potentially uncover new details in the images.

Conclusion

Pursuing astrophotography is more than just capturing images of the night sky; it’s a journey of discovery and contribution to a greater understanding of the cosmos. By meticulously observing, downloading, and processing data from celestial objects like the Whirlpool Galaxy, we enhance our appreciation for the universe’s beauty and share valuable insights with the astronomical community. Whether raw or processed, the data from the Stellina telescope is a powerful tool for education and inspiration. As we refine our techniques and share our findings, we become active participants in chronicling the universe’s grand narrative.