Astronomical Photographs
The following pages contain astronomical photographs accompanied by a brief description of how they were taken. All were taken from a site that has very bad light pollution, but with a little effort and a computer surprising results can be achieved.
It should be noted, however, that in order to keep loading time to a minimum, I have used the lowest resolution I could get away with. The images shown here, although representative, are not as sharp as the original photographs. I thought you would appreciate not having to sit in front of a dead screen for minutes on end to see a slighter sharper picture.
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Technical stuff for those that may be interested, if not, click a link.
All the photographs were taken through my telescope which is an 8 inch Celestron using a Schmidt-Cassegrain optical design. It is mounted on a Super Polaris German Equatorial Mount which is motor driven in both axis. For ease of use I employ a hand held Digital Setting Circle, NGC-microMAX, with a modest database of deep sky objects and a very useful Goto function. The Celestron has a focal length of 2032mm and is rated at F/6. I employ the use of a plastic dew shield which wraps around the tube and extends forward by a foot thereby reducing direct glare falling directly onto the lens from nearby street lights. I use an electrically heated Dew Zapper to prevent dew forming inside the tube, an essential piece of equipment for the Celestron.
For wide angle shots I use a Lumicon Easy Guider to attach the camera to the telescope. This gives a total magnification of X 7. For higher magnification I use an eyepiece of X 200 magnifications and attach the camera via a tele-extender tube. This gives a total magnification of around X 800.
My camera is a 17 year old Canon AV1 and serves the purpose well. I always use Kodak Gold 400 colour print film, but any fast film will do although some do have a colour cast. The use of a shutter release cable is essential and a timer delay is very handy, it allows time for vibrations to damp down before the shutter opens. You will hear that transparencies give better results than prints, this is true, but you need special equipment in order to scan them into a computer, and the images are of course a lot smaller. So unless you can achieve good results without computer enhancement, you will have to use prints as I do.
Having taken the photographs I take the exposed film to a local shop who know to develop all the frames by hand. The computerised system usually skips over star fields as 'no picture'.
The resulting pictures are usually below average quality. I live in an area with a badly light polluted night sky. It glows orange! This severely restricts how long my time exposures can be. Ideally a feint object, such as a galaxy, requires around 15 to 30 minutes or so exposure time, but by then the background sky glow completely washes out the image of the galaxy. So feint objects require that I move to a dark sky site. A lot of hassle! In order to achieve decent quality images without moving to a dark sky site I take relatively short exposures of just 2 or 3 minutes and then scan the poor contrast photos into my iMac and work up the images in Adobe Photoshop. Without this the images would be very faint, but with computer enhancement even short time exposure photographs can yield remarkable detail.
I hope these astronomical images will encourage others to take up the hobby. You do not need a perfect, dark night sky. You do however need a lot of patience!
Any comments or questions, contact me: EMAIL
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