Astrophotography with a tripod

Astrophotography from a tripod is quite simple. A big and expensive telescope is not necessary at all. Very nice pictures can be obtained even with quite basic and simple equipment.

A solid tripod, a fast film, and a camera with a fast lens is all that is needed. The speed of the film should be at least 400 ASA. Faster films with 1000, 1600 or 3200 ASA are better and sport nowadays a finer grain than years ago. The lens should have a speed of 1:2 or faster, i.e. 1:1.7 or 1:1.4. Point and shoot cameras usually have very slow lenses of 1:4 and slower and are not usuable for this type of astrophotography. The camera should have a cable release and a "B" (bulb) setting for manually controlled exposure times of several seconds duration. SLR cameras with a standard 50 mm lens usually fulfill these requirements.

Due to earth's rotation the stars seem to move around the celestial pole. This movement limits the exposure time. Longer exposure times will show the stars not as dots but as short lines. The maximum exposure time depends on the distance of the photographed area from the celestial pole. Using a 50 mm lens exposure times between 20 and 45 seconds are possible.

This technique is very well suited to photograph constellations. On the one hand many more stars appear on the picture than can be seen with the unaided eye and on the other hand there are not so many stars on the picture that you can't find those stars that make up the constellation. And as a bonus you can see the stars in colour! The comparison with a good star chart reveals that the faintest recordable stars with a 1:2 lens and 400 ASA film are 8 mag. With very fast telephoto lenses and extremly fast films even non-stellar objects are recordable although the maximum exposure times are reduced with increasing focal length. Examples are the Black&White picture. But don't expect too much, because you are reaching the limit of photography from a tripod. For better results you need an equatorial mount and guided exposures.