Re: Coma /Collimation
Bob Luffel (bobl@hpgrla.gr.hp.com)
Tue, 9 May 95 17:07:43 MDT
> > >
> > No it is not clearer to me. As I see it the focuser still points at the
> > same point. Racking in or out does not change the angle of the focuser
> > to the optical axis. A poor focuser that wobbles this might be another
> > story.
> > My 2 bytes worth
> > Bob Pfaff
> >
>
> Ok. let me try a shorter explanation.
>
> Where the focuser points does not matter with a cheshire. What matters is
> where the eyepoint is relative to the optical (not focuser) axis. Moving the
> eyepoint along the focuser axis will move it toward and away from the optical
> axis, if the two are not aligned.
>
> This will not work for a laser collimator, it works for a cheshire.
>
> Chuck
>
>
>
Is it true that a cheshire only gets you aligned laterally on-axis
and not parallel to the optical axis? I hadn't realized this (then it
is no better than a simple sight-tube, except it is perhaps easier to use).
Bob