Re: [APML] Calibrating STV axes independently

["Steve..." <swalters@worldnet.att.net>]

Joe,

I also had trouble using an ST4 with GEG and Meade 12" SCT until I added a
compressor on the guiding port. The guide stars went from seagulls to ovals
and the ST4 would guide well. So you should be able to get your system to
work. I often had trouble getting bright enough guide stars and frequently
had long integration intervals, 10 sec sometimes. But I was able to guide my
MI-250  with good results.

Since getting the STV, I haven't used that configuration but the STV is
quite a bit more sensitive than the ST4 and also guides with greater
accuracy. It caculates the centroid with greater precision and also has
smaller pixels. This would probably be beneficial for you.

But, you should be able to get good results with your current setup, I'd
concentrate on that before forking over $$$ for the STV. If the ST4 isn't
working, it is possible your problem would continue with an STV. So I'd
concentrate on getting the ST4 to work before considering getting an STV.
Start by using a pretty bright guide star and then move to dimmer ones. You
should be able to get this working in your front yard without imaging.

My $0.02, and worth every nickel :)

Steve...

----- Original Message -----
From: "Joseph/Leslie Schaefer" <schaefer@htva.net>
To: <astro-photo@seds.org>
Sent: Friday, June 14, 2002 3:00 PM
Subject: Re: [APML] Calibrating STV axes independently


> Don, Steve,
>    Thanks for the information on the prom update to enable separate axis
> calibration speeds.
> I was wondering if you think the STV is more sensitive and capable of
> guiding on dimmer stars?
> The deluxe version is very tempting but I wouldn't spend the extra money
> unless its capable of
> guiding on dimmer stars.
>   I have not been successful in guiding my C11 / GEG /ST-4 configuration.
I
> can't get the star value above
> 5. I plan on trying the software that came with the guider on my laptop to
> see what the guider is seeing.
>  With the trouble I am having with the ST-4 I fear that I wouldn't be able
> to get passed the "Seagull" shaped star problem you mentioned.
>  Thanks, Joe.
>
> ----- Original Message -----
> From: steve banbury <banburys@sonic.net>
> To: <astro-photo@seds.org>
> Sent: Thursday, June 13, 2002 11:14 PM
> Subject: Re: [APML] Calibrating STV axes independently
>
>
> > Joesph--I'd second what Don says.
> > I have had some excellent results with my STV (or -V as Jim calls it)!
> > It is very picky about round stars. "Seagull" shaped stars associated
with
> a
> > Lumicon GEG and a pickoff point
> > on the camera side of the focal reducing lens in the GEG drove my STV
> crazy. Use
> > of a Lumicon 2.5x
> > focal reducer on the f10 pickoff point in front of the GEG reducing lens
> > completely eliminated that problem.
> >
> > The eFinder mode of the STV is vastly easier to use than the ST4. And a
> 135 mm
> > f2.8 Nikon telephoto that can be
> > purchased used for about $40 or less will guide a 2000 mm scope with no
> problem.
> > Except of course if the scope
> > is an SCT with mirror shift. I had to learn this fact the hard way.
> >
> > I switched to a refractor to allow me to catch some of the widefield
> objects,
> > and to benefit from the eFinder capability of the STV. I know the
> independent
> > calibration of the 2 axes is the reason for the version 1.04 download
> software
> > provided, and when I get this one last issue sorted out (and only then)
> I'll
> > probably sell my ST4!
> >
> > Steve
> >
> > westergren wrote:
> >
> > > Joseph,
> > > My STV has so many features packed into it, in ROM (or PROM) that
> originally
> > > SBIG was running out of room to include the independant axis
> calibration.
> > > They figured out how to include it about a year after the STV became
> > > available.  The upgrade to the ROM program (downloadable via the
> internet)
> > > is also a feature that is not available to the ST-4.
> > >
> > > I have experience with both the ST-4 and STV.  They both guide to give
> great
> > > astrophotography (pin point stars), but the extra features of the STV
> make
> > > it a remarkable and much more useful camera/autoguider.  Is it worth
the
> > > extra $?  It is if you have the extra $.
> > > Don
> >
> >
> > --  APML Archives at <http://astro.umsystem.edu/apml/>  ---
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>
>
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