Meet Mark

The solar imager you may know as @azastroguy

Mark Johnston is a solar astrophotographer and the author of The Solar Observer’s Handbook. His solar work has been featured as NASA's Astronomy Picture of the Day, as well as reference images for the American Astronomical Society, and in Sky & Telescope, Astronomy, and National Geographic magazines. He’s also been sharing astronomy through public events for more than 30 years and has served as a NASA Solar System Ambassador since 2018. That combination of practical imaging experience and years of teaching makes him the perfect instructor!

Mark Johnston

Instructor

A Lifelong Interest in Astronomy

Mark grew up in Toronto, where a view of Saturn through a small backyard telescope helped start a lifelong interest in astronomy. Now based in Scottsdale, Arizona, he has spent more than 50 years enjoying astronomy.

His work today brings together solar astrophotography, public observing events, tutorials, and teaching. You may have seen his images online under @azastroguy, or met him at a star party, school program, or astronomy presentation.



Mark has been giving volunteer astronomy presentations and running star parties since 1990. His outreach includes school programs, public solar observing, resort astronomy events, and cruise-ship presentations.

At the Galactic Course, Mark teaches The Complete Solar Image Processing Workflow, bringing his experience to students who want to understand how to process their solar data.

  • Solar Astrophotography by Mark Johnston Tutorial
  • Solar Astrophotography by Mark Johnston Tutorial
  • Solar Astrophotography by Mark Johnston Tutorial

Decades of Sharing Astronomy

Mark has been giving volunteer astronomy presentations and running star parties since 1990. His outreach includes school programs, public solar observing, resort astronomy events, and presentations on cruise ships.

He has been a NASA Solar System Ambassador since 2018. His NASA profile credits him with hundreds of public outreach programs and introducing thousands of people to astronomy through his telescopes.



  • Astronomical League: Master of Outreach.
  • Night Sky Network: Exceptional Outreach Award.
  • Phoenix Astronomical Society: Vice President.
  • ACEAP: 2024 Astronomy in Chile Educator Ambassador.

You can read more about his astronomy programs and outreach on his website.

Master Solar Image Processing

Follow The Complete Solar Image Processing Workflow, with stacking and detail recovery, color, mosaics, and time-lapses. The course includes written lessons, video demonstrations, quizzes, and downloadable practice files. Visit the course page for the full curriculum and more information!.

View Mark's Course

Solar Photography, Published and Recognized

Mark has captured and processed thousands of solar images using different telescopes and cameras, including hydrogen-alpha, Calcium K and white-light setups. His teaching draws on all of that practical experience, so that you get the very best learning possible.

His photograph Sunspot with Light Bridge was selected as NASA's Astronomy Picture of the Day on May 17, 2023. It shows fine detail around a sunspot crossed by a bright bridge of solar material.



His astrophotography has also appeared in Astronomy Magazine, Sky & Telescope, BBC Sky at Night Magazine, Space.com, and Digital Camera World.

Take a closer look at his solar time-lapse featured by Space.com, or the Digital Camera World feature on his solar images.

Mark Johnston's Awards & Features

Learn solar processing with a REAL expert. Mark's work has been featured in the following and many more:

  • AAS Logo
  • Astronomy Magazine Logo
  • NASA Logo
  • BBC Sky At Night magazine
  • Digital Camera World logo
  • Live Science Logo
  • Nat Geo Logo
  • Sky and Telescope logo
  • Space.com logo
  • solar astrophotography by Mark Johnston
  • M101 the Pinwheel Galaxy
  • Sun in Calcium K tutorial

Author of The Solar Observer's Handbook

Mark wrote The Solar Observer's Handbook for people who want to understand, observe, and photograph the Sun.

The guide covers hydrogen-alpha, white-light, and calcium-K observing and imaging. It brings together equipment advice, explanations of solar features, capture techniques, and processing guidance, including stacking and sharpening.

It is a practical reference for visual observers, solar photographers, and astronomy educators.

His Galactic Course lessons offer another way to learn from that experience, with demonstrations and files you can process yourself.

Why I Chose Mark for the Galactic Course

My goal is for the Galactic Course to eventually cover every single aspect of astrophotography, all in one place. But knowing a lot about a subject does not mean I'm always the best person to teach it.

Solar imaging is a perfect example. Although I have some experience, I don't consider myself a true expert. Even if I knew 90% of a subject, I would not feel comfortable pretending to know the remaining 10%, especially when you trust me with your learning.

That is why I chose to work with Mark, someone I admire and fully trust in this field. His decades of experience photographing the Sun, his excellent book, and his years of sharing astronomy with others are why I am very happy to have him as your instructor.

Antoine Grelin

Learn Solar Image Processing with Mark