Flamsteed AS Astrophotography w/ Tony Sizer

Flamsteed Astronomy Society

“Getting started in Astrophotography” workshop with Tony Sizer — April 20, 2009

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Tony Sizer ran through an overview of astro- photography for beginners and showed us the kinds of equipment and techniques that can be used to get started.

Firstly, Tony explained the advantages of digital imaging compared to film, for photographing the night sky. His advice — “Forget Film!” Digital photography is now so much simpler than film, especially for the beginner, and can match all the previous strengths of film.

He then took us through each of the camera technologies which can be used for astro imaging — digital cameras, digital SLR cameras (DSLRs), webcams, and full-blown astronomical CCD imagers. Tony explained something of the technology in each case and talked about their strengths, weaknesses, and price ranges.

Digital Cameras (non-SLRs)

Regular digital cameras (not having interchangeable lenses like SLRs) can be used to produce quite presentable images of bright objects, especially the Moon, but they are very limited in what can be done with them. Either the camera must be hand-held against the eyepiece of the telescope, or an adapter or custom-made clamp used to hold it in place and keep it aligned. Great patience is going to be needed to hand-hold the camera and anything other than a short exposure will give a blurred image.

When using a regular digital camera all the optics of both the camera lens and telescope eyepiece are in the light path and the image will be dimmed. Also, unless the camera has a ‘manual’ exposure setting to allow control of both aperture and shutter speed, the automatic exposure settings will tend to average the exposure for the field. This will likely over-expose the target object eg planet, against the dark background. Focus will also be tricky. The best approach is to set the camera for distant scenes (often a mountain symbol).

Nevertheless, digital cameras can be used to produce striking images, especially where it hasn’t been possible to arrange an adapter or clamp. The two images on this page, taken through the Greenwich 28-inch and a Coronado H-alpha, are excellent examples.

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The Moon through the ROG 28-inch Great Equatorial. Hand-held digital camera, Jan 16, 2008, by Mike Dear