The paralactic mounting is an absolutely essential device in astrophotography.
It makes precise movement of the camera during exposure possible. If we
try to take photographs using a fixed tripod the Earth's rotation would blur
the image significantly after just a few seconds. I constructed this paralactic
mounting originally for photographing of Halley's comet in 1986. Between 1989 – 90
it underwent a thorough reconstruction whereby I replaced the manual control
with an electronic one (integrated timer/oscillator 555 circuit used).
The mounting is suitable for exposure times up to 20 minutes with focal
lengths of the lens up to 300mm. I use the Monar 5/500mm lens for
an object pointing. In the picture, a Praktica camera with the
Tair 3 4.5/300mm lens is mounted as a counterweight. This
paralactic mounting I have used to take several hundreds of pictures
of the Hyakutake comet (1996) and Hale - Bopp comets in (1997).