Ad Astra Observatory

Hi Jim,

Glad everything’s working. Thanks for the report.

BTW, I just finished revamping my digital setting circles web site and
linked it to my blog. I posted some information about the USB mod that
you sent me to my blog, so hopefully other interested folks can find

and use the info.

With respect to the alignment process, I’m not sure what you’re asking
me. The ASCOM standard pretty much dictates that the alignment
procedure be done either in the telescope driver (as is the case with
my system) or in the telescope itself (in the case of those telescopes
that have digital setting circles and motors and supporting
electronics built in). ASCOM doesn’t have built into it any ability to

do the alignment procedure and calculations for you. The procedure
that you use with my system was written by me, not the ASCOM folks. If
you wanted to customize that procedure, you’d either need to write
your own driver or modify the one I wrote. I’m certainly open to
sharing the source code for my driver with you if you want to modify
it to show a custom set of alignment stars. My preference would be to
simply fold your enhancements into the existing driver and release a
new version (which would, of course, acknowledge your contributions).

That being said, there is a method in the ASCOM driver API that would
allow you to ask the telescope driver for raw encoder positions. My
driver doesn’t implement those methods, unfortunately (I think they
were added to a newer version after I wrote my driver). Frankly, it’d
be easier to just to skip the ASCOM driver and talk directly to the
encoder interface. And the downside is that you’d have to write your
own coordinate transformation routines.

Not sure if this answered your question or not–let me know.

Dave

On 10/22/07, Jimbo S. Harris <jimbo@jimbo.net> wrote:
> Hi Dave,
>

> Finally got a clear night and a chance to test the interface.
>
> In short, it worked.
>
> I initialized and aligned, then pointed to a nearby object, which placed it
> in the 0.8� FOV of a 32mm eyepiece in a 2000mm SCT. With a little more
> alignment accuracy (I was aligning at 13x into a box that was probably 12′

> or more across; in that scope, the object was more or less centered), I’m
> sure it would have plopped the object right into place.
>
> With my sloppy alignment, the RA and Dec values still worked almost
> completely dependent upon their respective axes (as I expected; I have a
> permanently-mounted observatory, with a mount that is polar aligned to

> within an inch of its life).
>
> Now that I have the hardware end of things pretty well knocked together,
> I’d love to pick your brain on the software side of things.
>
> I have a couple of questions re: the alignment procedure.
>
> I’m thinking that I might want to re-vamp the alignment procedure in the

> software program I’m writing. My program can filter the alignment stars by
> what’s up at the time, so I’d rather be able to pick from that list, if I
> can. Do you know if there’s a way to do this alignment via ASCOM API? The
> idea is that I would pop up dialog boxes similar to yours (0�, 90�, star 1,
> star 2), but I’d want to read off the encoder positions via the ASCOM

> driver. Where is the alignment information stored, once your internal
> alignment routine runs?
>
> Any insight you can lend would be wonderful. I could probably be convinced
> to comp you a copy of the software once I get it talking to your DSCs, if
> that helps. So far, this application is just to help me choose DSO targets
> and point the scope at them, but I can see where it could grow into a

> toolkit that handles a lot of observing (and photography) tasks.
>
> Thanks for your help so far!
>
> Best,
> Jimbo
>
>