[Aavso-photometry] OT: Using alt-az for imaging?

[Roland Roberts]

Roland Roberts wrote:
> This is off-topic, but I've been given permission to buy a new scope 
> from the "appropriates committee" :-) and since right now I've been 
> using a 5-inch achromat, I'm looking for a big jump in aperture. 
>   
Jim Roe says I'm not off topic so long as I promise to do photometry 
with the scope :-)

Well, that *is* why I'm planning to get something bigger, so....

I currently have an ST-7XE and for the time being I'll be sticking with 
that since the money pool isn't infinitely deep.  If I can find a used 
ST-8XE (or the XME) I would probably try to jump up to that since the 
increased focal length is going to hurt my field-of view.

I was hoping to join in some of the CV monitoring fun.  I sometimes work 
with junior-high and high-school level students giving them a feel for 
doing research and data analysis so the ability to do short period 
variables is good.

I realize that if I keep the altitude moderate, I can probably get away 
without worrying about field rotation for short exposures, up to maybe 2 
minutes (very dependent on where in the sky).  Unfortunately, my 
location in Brooklyn, really requires I stay pointed above 30 degrees 
and ideally above 45.  So an alt-az will aways be a trade-off for me 
between staying high and avoiding the zenith.

I've been reading the ascom site and found that the ascom rotator spec 
does not cover using a rotator for field rotation correction.  I've just 
more-or-less gotten up to speed with using ACP 
(http://acp.dc3.com/index2.html) for automating image acquisition, and 
am hoping to continue doing that, so now I have to find out if it is 
possible for it to work with a field derotator, too.

Any tips or cautions are appreciated.

TIA,

roland

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Roland B. Roberts, PhD                             RL Enterprises
roland at rlenter.com                            6818 Madeline Court
roland at astrofoto.org                           Brooklyn, NY 11220