A Glimpse into Astrophotography

A Glimpse into Astrophotography

After our post about ...an Itty-bitty Universe the question was raised as to how such images are produced. For answers I turned to the publisher of "Year in the Life of the Universe", "Capturing the Stars", "Treasures of the Southern Sky" and "Lessons from the Masters", recipient of a "Hubble Prize" for contributions to astrophotography, image producer for both a UK and German national stamp, and the guy responsible for Apple's ubiquitous desktop image of NGC 3190. Meet astrophotographer Robert Gendler.

robert gendler fstoppers photography stars gallaxy astronomy desktop os x

Kenn:“In what form do these various frames of data come to you?”

Robert: “The Suprime Cam Detector produces data which is not very easy to extract. As you can see the data comes in “blocks” which are further subdivided into 4 strips.”


robert gendler fstoppers photography stars gallaxy astronomy 002


“These have to be cropped from the block, processed and then meticulously stitched into a mosaic. This process alone can take me a week or two working several hours nightly on the computer. Once the greyscle mosaic is created the image is then colorized using a variety of methods.”


Kenn: “What software and techniques do you use to put these images together?”

Robert:“Usually there is only single band data on the Subaru archive so there often isn’t suffient data to make a tricolor image from Subaru data alone. I obtain color data either from my own inventory of image data over the years or from others or from the Digitized Sky Survey. I use conventional programs like Photoshop, Maxim DL, Registar, Noise Ninja.”


robert gendler fstoppers photography stars gallaxy astronomy 003

The resulting images are nothing short of awe inspiring.

NGC1999-Subaru-HST-DSS-M robert gendler fstoppers photography stars gallaxy astronomy
NGC 1999, Emission and Reflection Nebulae in Orion
Composite Image from three Data sources
8.2 Meter Subaru Telescope (NAOJ)
Hubble Space Telescope
Color Data: Digitized Sky Survey, Robert Gendler
Image Assembly and Processing : Robert Gendler

For more of Robert's stellar work, head on over to his image gallery.

Log in or register to post comments


Fascinating. I’d love to see a video on how this is done. I’d always assumed you just pointed a (large) tube full of mirrors and glass at the sky and clicked the shutter. I had no idea there was so much work that goes into the processing of the data. Makes me want to learn more about the process!

Rob Gendler is one of the best in the business and his work is inspirational. Many astrophotographers use cooled CCD cameras with monochrome chips dedicated to this task. Color images are often created by first shooting light frames using red, green and blue filters (and/or other narrow band filters such as hydrogen alpha, oxygen III and sulphur II), subtracting dark and flat frames to eliminate noise and imaging train artifacts respectively, assigning the resulting individual frames to luminance, red, green and blue color channels, aligning them precisely with one another, and then combining them to produce a color image. It sounds pretty straight forward but in practice is MUCH more difficult. Rob makes it look easy. The link below is one of my images of the Veil Nebula shot using narrow-band filters and mapped to create false color.


Lee Christiansen's picture

Wonderful work... And to think - we sometimes moan about the amount of work with RAW over shooting JPEG...! This takes real patience!

Gregory L'Esperance's picture

Too high, in every sense of the word!!