Thomas Roehr wrote:
"...please do not ask me WHY, but with the new lunar.dll there is no
longer a "floating-point error: overflow" at the start of GUIDE ???"
...which is _especially_ odd, because the LUNAR.DLL is used only by
the 32-bit version, not the crashing 16-bit version! Something else
must have been 'nudged' by all this activity?
Jost Jahn pointed out:
"...Solar eclipse list: Nice, but you cannot point directly after this
to a map. After some left and right cliks it works..." Which is what I'd
expect. (Or, you can hit ':', the hotkey to show the current solar
eclipse.) I have some thoughts to rig it up so you can use 'Show Eclipse'
instead. But you can't do it that way right now.
"...Using MPC_OBS.TDF is a fint thing. But If I use satellite positions
of the SOHO comets, Guide is running wrnog with misinterprating the
second line as data." True. Truthfully, I had not really thought much
about SOHO. It would be a minor problem, except that some people (like
me) put all their MPC e-mails in one big file, so the SOHO oddities show
up.
MISSING PLANET FEATURES:
I mentioned a few e-mails back that I'd caused trouble in the 30 January
version of Guide:
"...previously, there were far too _many_ lunar craters. I'd had
some requests for a way to filter them out, and had done some work on
this. You can hit Alt-. to get more features, and Alt-; to get fewer
features (the steps are about 50% each time). It _should_ be that, if
you hit Alt-. enough, names will begin to appear."
This is still true. What I'd not realized is that it's common for the
initial feature density to be zero. In that case, hitting Alt-. enough
times just adds 50% to zero. (Sound of head banging into wall)
Until I post an update, the 'workaround' is to edit our old pal,
STARTUP.MAR, and find this line:
79 pl contr 50 214 0
Change that '0' at the end to '60'. That's a good starting value for
the density of planet features. And after that, too, you'll be able to
hit Alt-. and Alt-; and add and subtract 50% from a non-zero value.
COMPUTING ARTIFICIAL SATELLITE POSITIONS:
Markus Kempf pointed out that you can compute artificial satellite
positions quite briskly, using SGP4. He's right... but I think most
folks dealing with home-brew scope tracking hardware are not going to
be enthusiastic about elaborate software and algorithms. I've known
very few good software guys who understand hardware, and most of the
people e-mailing me about scope hardware want to work in (at most)
BASIC, and to do as little programming as possible.
In case I'm wrong about this... C (and C++) devotees should take a
look at the following source code:
http://www.projectpluto.com/source.htm#sat_code
It's a pretty clean implementation of SGP4, which ought to be a bit
faster and (in my humble opinion) much easier to understand and use than
most versions.
TYCHO-2:
Tycho-2 is now available to the world. (Which means I no longer need
worry that Guide 8 will be delayed because of it...) Details are at:
http://www.projectpluto.com/datasets.htm#Tycho_2
Incidentally, it appears that Tycho-2's links to the CCDM (Catalogue
of Components of Doubles and Multiples) ought to let Guide 8 do a _much_
better job of showing doubles and binaries. I'll probably be posting more
about Tycho-2 in coming months; in particular, I'd like to get it into
the hands of astrometrists, for reasons described at the above link.
OPEN CLUSTERS/GALAXIES:
Derek, if Jeff Medkeff is attempting to clean up open cluster data,
it's a Very Good Thing Indeed. Guide uses the Lund catalog, and I'm
embarrassed to admit that fact; the positional errors in this catalog,
even for bright OCs, are appalling.
-- Bill