AstroPhotography - Capturing the Night Sky

5 minute Exposure Looking North East - Photographed using Manually
Operated Barn Door Tracker
Constellations: Corona Boreals - Hurcules - Bootes - Part of Draco

Many years ago for Christmas I received a small dime-store variety telescope. It was one of the reflecting types using a smallish 2 1/2 maybe 3 inch mirror and a single low power eyepiece. With that simple device another dimension of the night sky opened. I was able to easily see craters on the moon and when pointed to a dark patch of sky, new stars became visible. The moons of Jupiter spread like shining diamonds shifting their position each evening. On one evening, a particularly bright object caught my attention and I pointed the telescope toward it. After a few moments of searching trying to center the object in the narrow field of view, a small, somewhat fuzzy object appeared. To either side looped what appeared to be handles. I withdrew my eye from the viewer...then looked again. Saturn!...the ringed planet. There was no doubt what it was even to my limited knowledge.

I've never owned a quality telescope...just too expensive, but I've always wanted to own one. Oddly enough the last couple of years I've started exploring another aspect of photography I never realized was so relatively easy to do; AstroPhotography.

Photographing the night sky does not require a lot of special equipment. Almost any lense from 50mm on down to 16mm will work. A tripod is a must and for the most part a remote shutter release is all but required. What is most important is a dark sky and that requires getting away from the light pollution of the city. The darker the better. Photographing the moon is less of an issue because it is so bright, but to capture the night sky...constellations and even the Milky Way haze...the sky must be a moonless, dark night with clear skies.

500mm - Tightly Cropped

This type of photography can be as complicated or simple as you want to make it. One easy way is to mount your camera on a tripod...set the exposure to manual / Bulb using manual focus set to infinity, and an ISO of 800 to 1600. The aperture should be opened to the maximum your lense will allow (f3.5 / f/4.0 is common)...attach the remote release...point the camera toward a patch of clear sky...press and hold the release and count to thirty. You will be surprised at what you will see. Using up to a 50mm for thirty and even 45 seconds will not produce any noticeable 'star trailing' caused by the rotation of the earth. For longer exposures, you will need some kind of tracking device.

Shanty Hollow - Includes Part of
the Milky Way near the top

Tracking devices are contraptions that allow the photographer to rotate the camera on the same plane as the stars to follow the stars across the sky for an extended period of time. Of course you can purchase expensive computerized equipment to do this, or you can build one that will work remarkably well. They are called 'Barn Door Sky Trackers' and there are numerous designs ranging from simple hinge types to more sophisticated contraptions that rival professional quality equipment. Some of these are motor driver, but many of the simpler ones are driven by hand.


I recently built one and spent some time trying to make it work...with mixed results...more because of the operator than the design. I discovered that the key ingredient to make for proper tracking is an accurate setup...it has to be oriented to the Pole Star to allow for correct tracking. What started as a simple design has evolved into a system with fine tuning dials and spotter scope pole star orientation...I'm still trying to find the right combination.

AstroPhotography is a fascinating way to explore the night sky and provides another avenue of artistic expression. This summer I hope to explore this method in more detail.

Keith