Polaris isn't actually at the celestial pole. I forget how far off
it is, but I'm guessing that's what your circle represents - the
distance from the pole.
In my Losmandy scope, there are multiple lines going from the center
of the reticles rotation. One of them has a "gap" into which you
place Polaris.
Two of the other lines have need to be lined up with two other stars
(don't have charts with me, so I don't know which they
are - the are typically the only other bright-ish stars in the
field). These lines too have "gaps" for these stars to be positioned in.
Three points give you absolute orientation. Once you have all three
stars centered in their respective gaps, you are assured that you
are aligned. The patience part come in in that you need to rotate the
reticle, then change your alignment, then rotate again, then change
again, etc, etc. Eventually you get the rotation correct, and the
stars just fall into place.
The reticle also has diagrams of the dipper and Cassiopea that help
give you a start on the rotation.
Does that make sense?
Pete
>
> Here's a polar alignment question for you... My polar axis scope has a
> little circle in the middle and a position on that circle marked where you
> are supposed to "place" polaris so that it is properly aligned.
> Of course
> since it is a circle, I would assume that as long as polaris in on that
> circle it wouldn't have to be in that spot, since all you have to do is
> rotate that actual polar axis scope inside the mount for the spot to be on
> polaris..
>
> Did this make any sense at all?
>
> Robert. . .
>
> ----- Original Message -----
> From: Peter Santangeli <psantangeli@No-Spam>
> To: <sf-bay-tac@No-Spam>
> Sent: Thursday, June 29, 1999 12:44 PM
> Subject: First Light: JMI NGT-12.5
>
>
> > >.With a focal length this long, even a
> > > p.a. scope will not be accurate enough. You'll need to use the
> > > drift method.
> >
> > Not sure I totally agree with this... I find that patience in
> > using the polar scope well gives me better results than patience
> > in drifting using a C11 at F6.5 or so. Polar scopes can be finicky
> > things, but once you get the hang of them you can do some pretty
> > decent alignments (again with patience... did I mention that
> > patience was required?:-).
> >
> > I've gone as long as 1hr45m (actually, last weekend) with
> > scope alignment with no noticable trailing.
> >
> > Probably depends on which technique you are most comfortable
> > and confident with.
> >
> > Pete
> >
> >
> >
>