Guide scopes.

[Dre]

Hello!

I'm just wondering what a guide scope is?

: - )

[Cornelius Varley]

Guide scope - a scope for guiding. For long exposure photography you need to be able to control (guide) the mount to minimise drift. In the old, pre-computer days, the guide scope would be a refractor telescope of about 1.5x the focal length of the imaging scope mounted on adjustable rings. The obverver would select a suitable guide star near to the imaging target and monitor the drift of the guide star in the the guide scope, giving small corrective commands to the mount. Today this guiding is done using software and a separate camera. The guide scope doesn't need to have a long focal length either, a lot of people are starting to use modified finder scopes (finderguider) to guide the mount.

Peter