Paul --

I don't think that a pointing model would be useful in the field.
However, for a permanently mounted scope, it might be worth doing the 20
- 50 points once.

It should also be noted that mirror flop is *somewhat* predictable.
Predictable enough for a pointing model to work out? That I don't
know....

-- Jeff.



________________________________

From: ap-gto@... [mailto:ap-gto@...] On
Behalf Of Paul Mortfield
Sent: Wednesday, February 28, 2007 6:14 PM
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.
thanks,
...paul.
p.s. Dave T. hopefully next year's Starfest will be non-raining,
so I
can look thru your scope.