Hi folks,
Those of you who want to edit Guide's lists of city names, or are
interested in the dataset of two million city names that Jost mentioned
a few posts back, or who would like to see an example of that data for
Australia, should take a look here:
http://www.projectpluto.com/random.htm
Regarding lists of events, such as occultations and conjunctions:
I regard this as being more likely, after the recent improvements to
the way the Help system works. The example I posted a few days ago,
where you can get a list of asteroid occultations, click on one, and
have Guide show you that event, has revised my thinking about how I
would do this. Generating similar lists, such as "mutual planetary
occultations" or "lunar occultations of bright stars", ought not to
be excessively painful. I think. (The main problem, as usual, is
lack of time.)
As Niels Foldanger points out, _Dance of the Planets_ has the
advantage of being able to numerically integrate objects. (I think
it's the only popularly-available software to do this.) Were Guide
able to do this, it could:
(1) Show certain deep-space probes such as Voyagers 1 and 2, Galileo,
Cassini, NEAR, etc.
(2) Show heavily-perturbed objects such as P/Lexell, which was ejected
from the solar system by Jupiter in 1770, and P/Shoemaker-Levy 9 (the
one that collided with Jupiter in 1994).
(3) Let you run experiments in which an object is added with a given
position/velocity, and see where it goes.
(1) and (2) can actually be more readily handled by pre-computed
ephemerides, of the sort Guide now uses to show outer satellites of
Jupiter, Saturn, Uranus, and Neptune. This yields greater accuracy
and convenience, since it works by doing immense amounts of math _once_
and storing the result. The third function would be rather pleasant to
have, but I must admit that it is somewhat outside the realm of things
I want to add to Guide!
James, you asked about Guide's handling of daylight savings time...
in general, Guide just uses whatever zone you've set. If you set
DST, it uses that for all dates. Set standard time, and it uses that
for all dates. This evades the fact that switching to DST is a local,
governmental matter (hence devoid of any logic or predictability.)
This reminded me that Australian/New Zealand users might want to
know about a way to switch Guide's list of time zones from the US
names (EST = -5 hours from UT, etc.) to a list of zones for those
countries. The way to do this is now described at
http://www.projectpluto.com/random.htm
-- Bill