Hi folks,
My apologies, but I've been a bit late in replying on this list...
as a result, this will be rather long, and I _still_ need to mention
a few items! Expect an extension in a day or two; there were a few
things discussed that I'm still trying to debug, or figure out a good
way to do, or am working on adding to the software.
SHUTTLE VISIBILITY:
I just read a newspaper article stating that the Shuttle launch was
seen "as far north as Long Island, New York".
It also said that this mission will install solar panels that will
eventually span about 240 feet by 38 feet. You have to wonder if we'll
get "super-Iridium" flashes? The area is larger, and the orbit is
lower. Balance that against (I assume) lower reflectivity, and (I
again assume) an attempt to keep the panels facing directly at the
sun. I suppose the precision with which the panels face the sun is
going to be the key factor.
ZOOM IN/OUT n LEVELS:
You _can_ add such buttons to Guide... a totally undocumented
function, but quite doable. One such button already exists, and
if you look at TOOLBAR.DAT, you'll see this:
2271 g!set_mi.bmp Zoom out four levels
To create a button to zoom out N levels, change 2271 to be 2275-N.
To create one to zoom _in_ N levels, change it to be 2275+N. To
create a totally useless button that doesn't zoom in or out at all,
change it to be 2275.
If you add a new button, instead of revising the existing one,
you should go to the top of TOOLBAR.DAT and increment the number of
buttons. Incidentally, there are assorted comments about TOOLBAR.DAT
at the end of that file.
CRASH OF 16-BIT GUIDE:
Thomas Roehr pointed out that the Win3.1 version of Guide is behaving
very badly indeed. I have tracked this one down and had hoped to announce
that the fixed version was posted... not quite yet, though; maybe
tomorrow (along with assorted minor improvements).
HOUR ANGLE UPDATING:
Dennis Means pointed out that when you move the cursor, all sorts
of figures in the legend (alt/az, RA/dec, constellation, ecliptic
and galactic coordinates) update to reflect the new cursor position...
but the hour angle value does _not_ get updated. Point taken.
Unfortunately, it's not a quick fix, and won't be part of the next
update.
Regarding the dropped text in 'RA/dec mode' animation: I'd suggest
using 'proper motion' animation in such cases instead. This causes the
entire screen to be updated. In Windows, the 'RA/dec mode' is almost,
but not quite, obsolete. (In DOS, I don't have much choice except
to use this mode... it really continues to exist almost solely for that
reason.) Incidentally, if you use _any_ mode except 'RA/dec', the
hour angle _will_ get updated (as will everything else).
DECAYING ARTIFICIAL SATELLITES:
I have indeed considered modifying Guide to handle "close-in",
decaying artificial satellites. The amount of work required is truly
daunting, but it _is_ a mathematically interesting problem... one
obstacle is that, were I to produce a satellite motion theory with
the necessary accuracy, I'd probably get the US Government _very_
annoyed with me, and would get my tax returns audited for the
remainder of my life. Some discussion of this is at
http://www.projectpluto.com/future.htm#satellite_model
FIXED SOLAR ALTITUDE ANIMATION:
Thomas Roehr also suggested that it would be nice to have an
animation mode with a 'fixed' solar altitude: that is, if you
started with the sun at altitude -18 degrees after sunset (astronomical
twilight), then the next 'step' would put the sun at the same altitude
at the following day. Animation 'steps' would usually be almost, but
not quite, one day.
The same idea came up about a year ago in a _Sky & Telescope_ article
by Stuart Goldman, discussing interesting/useful features missing from
astronomical software. I liked the idea then, and still do.
-- Bill