Utilizing Public Datasets for Stellar Image Production: A Guide by Sergio Díaz Ruiz
Interview with Astrophotography Guru, Sergio Díaz Ruiz
Meet Sergio Díaz Ruiz, an award-winning astrophotographer who creates breathtaking images using data from public sources. While he does capture his own astrophotography data, he's here to tell us why processing data from other sources can be an artistically rewarding choice.
Astrophotography Beyond Capture
When starting out in astrophotography, it's easy to focus on the shooting part – buying the best gear, perfecting your technique under dark skies, and snapping as many shots as possible. But for experts like Sergio, image processing might just be the most crucial step.
Deep-sky astrophotography is a unique beast because the actual image is built through processing, with no visual reference initially. As astrophotographers, we interpret this raw data through processing, balancing the information in a way that's communicative and visually pleasing. So, if we give due credit to image processing and embrace it as a creative, artistic process, then it's not surprising that existing, public data can be a great starting point for our work. It's our personal, unique interpretation that brings the data to life.
Finding the Raw Material
There are numerous sources for public data, but Sergio suggests starting with the Mikulski Archive for Space Telescopes (MAST) Portal hosted by the Space Telescope Science Institute (STScI). With advanced search options, you can easily narrow down by mission, instrument, and filter, browse potential targets, and preview images before downloading them. Other well-known resources include ESA Sky, ESO Science Portal, and the Junocam website, among others.
Amateur astronauts like Wei-Hao Wan (also a professional astronomer) often share their data on social media or personal websites or offer it for free. Subscription-based remote observatories that offer pay-per-use services are also becoming popular among advanced amateurs. These observatories sometimes provide sample master files that can be used.
Tools of the Trade
Sergio uses PixInsight for most processing steps, with a few exceptions like composing layers or manually cleaning artifacts in Adobe Photoshop. When blending multiple bands is necessary (as it often is with professional data), he relies on a command-line tool named dimred that performs a Principal Components Analysis projection to the CIELAB or Oklab color spaces.
There's no set workflow for Sergio; instead, he adapts to each image based on a common thread he has in mind. In terms of his own image capture, he uses a variety of equipment: a Skywatcher AZ-EQ6 Pro mount, Tecnosky 90mm F6 FPL55 APO and 0.8x dedicated reducer/flattener, Omegon veTec 571C OSC camera, a custom-made electronic focuser, an Intel NUC computer coupled to the mount, a ZWO ASI120MM-S camera for guiding, and a mix of Samyang and Sigma lenses.
Embrace the Process
With the growing number of tools and tutorials simplifying image processing, it can be tempting to take shortcuts. But remember, your role in astrophotography is to be a creator – not just a consumer. Stay curious, learn the process, and enjoy every step of the journey. Use tools to aid your productivity, but let your creative spirit guide your artistic process.
About Sergio Díaz Ruiz
As a child, Sergio was captivated by astronomy and at 20, took his first steps into astrophotography. He's an active member of the Astronomía Sevilla Association, the Andalusian Network of Astronomy, and the Federation of Astronomical Associations of Spain. If you're interested in learning more about Sergio, check out his website, sergiodiaz.eu, or connect with him on Astrobin, Mastodon, and Twitter!
The Power of Public Data in Astrophotography
In search of public data similar to what's available on the MAST Portal? Here are some resources you can explore:
- ESA Earth Online – While mainly focused on Earth observation data, this ESA portal offers a broad catalogue that can be valuable for general Earth observation.
- Hubble Images – NASA provides a wealth of images from the Hubble Space Telescope, including science images and mission operations images.
- Astrophysics Source Code Library (ASCL) – This library provides source codes for astrophysical applications. While not a direct repository for image data, it can be helpful for analyzing or simulating astrophotography data.
- PSRCHIVE – A suite for pulsar data archival and analysis, helpful for astrophotographers focusing on pulsars.
- NASA's Data Portals – Beyond the MAST, NASA offers various data portals for different missions like the Spitzer Space Telescope, Chandra X-ray Observatory, and more.
- Stellarium and Star Charts – Useful for planning astrophotography sessions or analyzing celestial positions.
- Sergio Díaz Ruiz, an astrophotography guru, emphasizes that image processing in astrophotography is a crucial creative step, often surpassing the capture process.
- Deep-sky astrophotography requires interpreting raw data through processing, balancing information to create communicative and visually pleasing images.
- For public data, Sergio recommends starting with the Mikulski Archive for Space Telescopes (MAST) Portal hosted by the Space Telescope Science Institute (STScI).
- Other resources for public data include ESA Sky, ESO Science Portal, Junocam, social media accounts of amateur astronomers, and subscription-based remote observatories.
- Sergio uses PixInsight for most processing steps, dimred for blending multiple bands, Adobe Photoshop for manually cleaning artifacts, and a range of equipment for image capture.
- Astrophotographers should embrace the artistic process, learn the tools, and let their creativity guide them, rather than purely relying on shortcuts.
