Re: keypad pointing models. Was: Re: Paramount ME vs. AP 1200GTO

Ray Gralak <rgr@...>

Hi Paul,

First you would enable a mode in the hand box that will enable the collection of
points and build a model from them. You then slew to your first target. If it is
not centered you center the object in the eyepiece and click Synch (or RCAL). A
correction point is then added to the pointing model. As you go through more
visual objects the pointing model becomes more accurate each time you add a

If you are not interested in having a pointing model or are using an external
model then you wouldn't use this feature. I think that building a model that
improves pointing accuracy as you observe would be pretty painless.



-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...]
On Behalf Of Paul Mortfield
Sent: Wednesday, February 28, 2007 10:14 AM
To: ap-gto@...
Subject: Re: [ap-gto] keypad pointing models. Was: Re:
Paramount ME vs. AP 1200GTO

Hey gang,
maybe I'm just missing something here from the visual users.

I occasionally use my mount for visual usually after an imaging
session and remove the camera and ya its a hassle to drag out a PC in
the cold so I too prefer the keypad. The objects were always in the
field if I stayed on the same side of the meridian. And even so, if I
did a meridian flip, I'd goto any bright star on that side, do a RCal
and I'm good to go for the majority of objects on that side of the
meridian. If its still off, RCal on a bright star in that target's
constellation and off you go again.

The biggest problem with doing a handpaddle model is how are you
going to enter a pointing model into the handpaddle, ie, every star
would have to accurately be centered in a cross hair eyepiece (don't
rotate the diagonal) then recorded. To do a good all sky model,
you'll need a bare minimum of 30-50points. I just can't see sitting
there and entering all this data, visually by hand. For imaging and
a fixed imaging train, there's wonderful tools to automatically do
that and do 100 points while you grab a bite of food.
Also, if you're using an SCT and don't keep the mirror locked from
day1, then its impossible to model the sky due to mirror flops,
rotating the diagonal and making sure you're always centered on axis.

In the field, the polar scope has always gotten me so close that I
don't bother drifting and again, usually a Sync in the beginning and
RCal if needed later on is all thats necessary. A little 50mm finder
scope or telrad makes everything so simple just in case.
For imaging in the field, I'm not gonna waste precious dark time
running a model, since usually I'm only grabbing 1-3 targets a night.
That way using the laptop/planetarium program its even easier to RCal
near the target. I also make use of Maxim's centering capabilities
talking to the mount and once again the target is where I want it in
a matter of seconds.

So please enlighten me to the visual side that I don't regularly do.
p.s. Dave T. hopefully next year's Starfest will be non-raining, so I
can look thru your scope.

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