Date: Tuesday, September 5th, 7:30 p.m.
Location: Danbury Hospital Auditorium
Presenter: Shannon Calvert
by Andrew Woodruff
with Shannon Calvert
Photographer and Graphic Artist (Easton, CT)
Shannon Calvert says he is learning about astrophotography. After more than a decade of work as a professional photographer, he branched into astrophotography a year and a half ago. When he embarked on the new field, he figured that, with his extensive background in conventional photography, it would be a cinch to strap a camera on the back of a telescope.
It turned out to be more complicated than that! Not surprisingly, he needed to upgrade his equipment. He bought a new telescope. And then another one. And he discovered a lot of computer image processing that is part of astrophotography. After a year and half of effort, Shannon describes himself as still learning as an amateur. He will share some of his newfound knowledge with us.
Shannon had an interest in astronomy 25 years ago. At that time, his wife had promised him a new telescope as a gift; however children and work took priority. Eventually his teenage daughter joined a local astronomy club for a school project, and Shannon helped out. After his daughter had completed her project, Shannon found he was still interested in astronomy. He finally took advantage of his wife’s gift offer and bought a used telescope. He chose a model that had earlier been his dream telescope and strapped a camera on the back end. That turned out to be an exercise in frustration.
He quickly discovered the more specialized requirements for astrophotography and upgraded to a more appropriate telescope. He explains that you need special glass to reduce chromatic aberration if you intend to use the telescope for photography. Shannon hopes to bring this telescope, which is a 4-1/2” refractor, to this General Meeting.
Shannon says he has been particularly surprised about how much computer work is involved in astrophotography. For example, most astrophotos require stacking many images. In terrestrial photography, Shannon says “you just take a photo and you’re done”, or perhaps you use Adobe’s PhotoShop to enhance the photograph. However, in astrophotography, you are typically working with very faint objects. You may take hundreds or even thousands of separate frames and then combine them in software. The combination of many separate photographs leads to a much better result than say just leaving the shutter open for an equivalent length of time. The computer processing also includes steps to map the sensor’s dark current and other details, all intended to bring out an image in what might otherwise look like noise. Shannon will explain these processing steps, demonstrate the software, and show us the results.
Trifid Nebula (M20)
Shannon vacationed for a week in July at the Maine Astronomy Retreat, where he created the two attached photographs. The Trifid Nebula (right) is a star-forming region within our own galaxy, while the Triangulum Galaxy (below) is over 2.5 million light years beyond the Milky Way. The dark sky in Maine was useful for both of these photographs. Shannon will show overhead slides of many more photographs. He generally focuses on galaxies and nebulae, rather than planets.
Shannon is looking forward to the solar eclipse on August 21. This will be a partial eclipse in most of the country and a full eclipse in a 70-mile band from Oregon to South Carolina. Shannon is traveling to Nebraska to experience the full eclipse in an area with good prospects for clear skies. And, if the weather cooperates, he will share his photographs with us.
Triangulum Galaxy (M33)
Shannon will describe how people can get involved in astronomy and astrophotography. He is involved with Westport Astronomical Society in Westport. This organization has an observatory with a soon-to-be-upgraded 12.5″ Newtonian telescope and a 25″ Dobsonian telescope (the largest available for public access in Connecticut). The observatory is open for public viewing every Wednesday night, weather permitting, and Westport Astronomical Society sponsors a lecture on the third Tuesday of each month.
Shannon owns the telescope in the foreground
When he is not learning about astrophotography, Shannon is a professional photographer and graphic designer. His firm HireImagination is a full-service design agency that provides marketing services.
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