Re: [guide-user] Running Charon on Windows 7

Bill Gray Feb 28, 2016

Hi Matt, Christian,

Thanks for the comments on this. I've tried Charon in DosBox, though not much.

As you know, Charon has been pretty much in "maintenance" mode for some years
now; I've not done much except to fix a bug or two, and I've added catalogs
such as UCAC-4 from time to time. I started on Charon in the mid-1990s. At the
time, the idea of being able to say, "the image is in roughly this part of the
sky; let's let the computer figure out the pattern match" was a revolutionary
thing, and the program got a good bit of use for a decade or so.

After that, I was very impressed with the work done by Brian Warner on
_Canopus_, Herbert Raab on _Astrometrica_, Bob Denny on _PinPoint_, and
various people on So I was content to let them take over the
field. To a large extent, they have... though as has been pointed out here,
there are some Charon "holdouts"!

I've thought about moving Charon out of the world of DOS and into something
more modern, ideally cross-platform. The problem is (as Christian can tell you)
that the code is mostly quite ugly and hard to work with. I have written some
very elegant code of which I am quite proud, but Charon is not that code.
Making bug fixes is difficult enough at this point; trying to move it to more
"modern" systems would be rather scary.

Besides that, I've since learned a few things about how automated astrometry
can be done. The project, in particular, got me thinking about
starting over from scratch with code that could do similar "blind" matching
(feed it an image and it will figure out where in the sky that image was taken,
instead of needing to know roughly where to look.) is _very_
impressive, but I do see some ways of improving it to make it a good bit faster
and the underlying system easier to understand (and therefore easier to maintain).
Fortunately, the people did a really good job of documenting how
they achieved their results, and I can stand on their shoulders and see a
little further.

I should warn you that while I find the prospect very interesting, it's
more of a "gee, I'd like to work on this" project than one on which I am actually
working. Projects that will bring in some revenue have had to take priority,
and will probably do so for a while.

Incidentally, regarding the "go to" A2.0 and B1.0 in Guide: I do see what's
broken with both of these. I've fixed A2.0, and should have B1.0 working soon.
Ideally, I'd like to get PPMXL working as well... that appears to be the
"catalog of choice" these days. (Essentially, it's B1.0 cross-referenced to
2MASS, resulting in proper motions, fixed magnitudes, and the elimination
of a lot of the errors/spurious objects plaguing B1.0.) But if I don't get
that working in the next few days, I'll at least post an interim fix to the
A2.0 and B1.0 issues.

-- Bill

On 2016-02-28 13:36, mgedawson@... [guide-user] wrote:
> Thanks Christian for the feedback; most of it was way above my head but useful anyway.
> Just to correct a couple of errors in my previous message, I am running Windows 8.1 not
> Windows 7. Also I meant to say I have been a happy user of Charon for 16 years not 26!
> Senior moment.....
> Anyway, this is what I did and Charon works as normal, no crashes, no bugs (though I
> haven't tried blinking).
> I created a folder on my desktop, unzipped Charon to this folder, then added my FITS
> images and copied dos4gw to this folder too (its on the Guide CD in the WATCOM folder).
> To open Charon drag and drop the Charon icon in this folder onto the DosBox icon,and use
> in the normal way.
> After measuring your image press 'Esc' to get back to the dos screen. Type 'charon' to
> load another image, or 'exit' to close Charon.
> There may be better ways (I arrived at this by a process of trial and error) but have
> not had any problems so far.