Hi folks,
Catching up on a few things here, so this will be a longer mail than
usual:
I've just posted an update (so far, only to the 32-bit Windows
software) that fixes assorted problems reported over the last few days.
I think I've gotten everything except the troubles DE Green reported;
still haven't figured out what's going on there.
The only actual "improvement", as opposed to a bug fix, is in the
Extras menu. I moved assorted RealSky/DSS functions into a dialog box
of their own. This box also shows up if you right-click on the corner of
an image, then select "more info". It provides access to all the image
functions that were previously in the Extras menu, plus the ability to
set the range of fields of view at which images are shown.
Philippe Mollet wrote:
"..(1) I wanted to know what part of the moon would have been captured
with my scope and webcam, but it seems that Guide draws the CCD-frame
first, and then puts the Moon on top of it (so the frame becomes
invisible)."
And the moon (and RealSky/DSS images) also overwrote aperture circles
and the border. All switched now, to draw in the proper order.
"...(2) Here are the specs for the Philips Vesta-webcam..." Ah, a good
thought... I have added this to CCDS.NAM.
Off-topic question: if anyone has succeeded in getting images of
stars, covering a field of at least a few degrees with a cheap Web cam,
please contact me via private e-mail. I've not abandoned my hopes of
using such a camera to make digital setting circles almost obsolete, as
discussed at
http://www.projectpluto.com/webcam.htm
though my own experiments with a Connectix gray-scale camera have been
less than encouraging.
Claude Serquet wrote:
"...(1) Time on trails is UT. Is it a way to change to local time ?"
Also fixed: the new version shows such times in the currently selected
time zone.
"Where can I find a description of the .tle file format ?"
http://users2.ev1.net/~mmccants/molcdesc.html
"...I played a little with the new possibility to set location on
probes and satellites...I encountered a problem when animating backward
to go back to earth, guide crashes when the date become before starting
date of the probe."
Also when you go past the "end date" of the elements (most of the probes
have the elements marked as expiring past a certain date.) I have no
really good way to handle this, but I've revised Guide to extend the
first and last elements available into the past and future. That is,
when displaying Pioneer 10 for dates before 1973, Guide will use the
elements for the first leg of that mission (an ellipse that basically
has a perihelion at Earth's orbit, and an aphelion at Jupiter's...
a "minimum-fuel" orbit). For dates after 2000, it just extends the
current hyperbolic elements.
"...I would appreciate to see the distance to the targeted object if
not too much work for you." For this, I'd either click on the targeted
object and then use 'more info', or use "Animation... Make Ephemeris."
Additional bug fixes: John Greaves pointed out (off-list) that some
user-added datasets that span multiple files, such as UCAC-1 and AC2000,
were broken; and that the Barnard dark nebula outlines were sometimes
resulting in extraneous lines zinging across the screen. All fixed now.
Possibly interesting factoid about that asteroid (5587) 1990 SB:
this looks as if it might conceivably be a member of the Alinda group.
These are objects that end up in a 3:1 resonance with Jupiter, meaning
an orbital period of about four years. The result is that Jupiter slowly
hikes up their eccentricity, until eventually, they cross the path of
a planet and get booted into some new orbit. (4179) Toutatis is probably
the best known example; its orbital period is almost exactly four years,
and it's made close passes by us in late 1992, 1996, and 2000 (right
around the dates of US presidential elections).
If (5587) is indeed an Alinda (and it may not be; its elements are
borderline), Jupiter may continue to boost its eccentricity until it
becomes an Earth-crosser, and a possible subject of concern to our
descendants in a few thousand years.
About Pat's suggestion of attempting to track objects at non-sidereal
rates: I have indeed considered this. It would be especially nifty with
artificial satellites, most of which travel well below the 8 degree a
second slew rate of an LX-200.
Main problem is that Guide would have to send a stream of coordinates
to the LX-200, so the scope would sort of jerk along to follow the object,
rather than smoothly following it. (Of course, for something as slow as
an asteroid, this is less of a problem!)
At one time, I think Mel Bartels was contemplating satellite tracking
as part of his AltAz system, possibly doing so by taking a closely-spaced
ephemeris from Guide and interpolating it. Dunno if that ever happened,
though...
-- Bill