RE: [APML]OT-Drift Alignment

["Serge Theberge" <serge.theberge@wti.on.ca>]

Hi Stuart,

I agree that boredom does put an upper limit to how much time you spend on
alignment!  However, I would think that there is a fairly big difference
between "enough alignment" for a 5 minute vs a 45 minute photo exposure for
example.

Serge

> -----Original Message-----
> From: astro-photo-bounces@seds.org 
> [mailto:astro-photo-bounces@seds.org] On Behalf Of Stuart Heggie
> Sent: Tuesday, November 25, 2003 8:09 PM
> To: Discussion of Film Astrophotography
> Subject: Re: [APML]OT-Drift Alignment
> 
> 
> Serge - knowing you'll get some very expert opinion I'll 
> offer this - drift align till you can't stand the boredom. My 
> attention span is not that long. I polar align my 
> SuperPolaris mount with the polar bore scope and run with it 
> but guide manually. I do end up making some adjustments in 
> Dec but they are not much and I've not noticed any 
> objectionable field rotation on lenses up to 180mm. I only 
> use the SP for piggyback. I drift aligned my G-11 for the observatory.
> 
> Stuart
> ----- Original Message -----
> From: "Serge Theberge" <serge.theberge@wti.on.ca>
> To: "'Discussion of Film Astrophotography'" <astro-photo@seds.org>
> Sent: Tuesday, November 25, 2003 8:01 PM
> Subject: RE: [APML]OT-Drift Alignment
> 
> 
> > I have been told that for astrophotography, not only you 
> must have a 
> > good, sturdy mount, but you must have good polar alignment.  I have 
> > seen various rules of thumb about what is "good enough" polar 
> > alignment such as no visible drift @ 200X for 5 minutes, 
> others state 
> > 15 minutes, etc.  My
> guess
> > is that there must be some kind of formula (or rule of 
> thumb) linking 
> > "maximum acceptable polar alignment error" to f-speed, 
> magnification, 
> > film grain size, exposure duration, etc.  Can anyone 
> enlighten me on 
> > this?
> >
> > Thanks
> >
> > Serge Theberge
> > Toronto Centre
> > RASC
> >
> > > -----Original Message-----
> > > From: astro-photo-bounces@seds.org 
> > > [mailto:astro-photo-bounces@seds.org] On Behalf Of 
> Franklin A. Holub
> > > Sent: Monday, November 24, 2003 4:25 PM
> > > To: Discussion of Film Astrophotography
> > > Subject: Re: [APML]OT-Drift Alignment
> > >
> > >
> > > I haven't posted in a while but lets see if I can really 
> mess things 
> > > up... I'm going to make a statement that is going to fly 
> in the face 
> > > of years of experience and is going to contradict what we have 
> > > always been told about drift alignment...
> > >
> > > But first, a little background...
> > >
> > > After a couple of years of being happy with "close enough" polar 
> > > alignment, I installed a perminant pier and I figured it 
> was time to 
> > > "nail" my polar alignment. <snip>
> >
> >
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> >
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