Re: [APML]: barndoor tracker question

[Bert Katzung <katzung@pacbell.net>]

Jim Fedina wrote:
> 
 Then I want to take
> a 10 minute exposure of Orion. the NCP is to the north while Orion is to
> the south. How do you mantain polar alignment while turning the barndoor
> drive? Is it that the barndoor drive stays pointing at the NCP and you
> turn the camera only? 
> Jim Fedina
Jim: You've got it--keep the hinge of the barndoor aimed at Polaris
(or the NCP, better) and turn the camera, using a tripod head. A ball-
joint type head works best. It needs to be raised high enough off the
surface of the barndoor to permit pointing the camera in any direction
without bumping into the barndoor.
Bert