About the three problems Pierre turned up:
Guide stores the information as to which items have been
installed in 'mark' (.MAR) files. That particular data should
be read in _once_, when the program starts, from STARTUP.MAR.
Instead, Guide could reset it every time it read a .MAR file.
Not a Good Thing... I've fixed this, and have posted a new
http://www.projectpluto.com/guide8.zip (still about 450 KBytes).
Pat Anway mentioned the WDS problem on-list a few days ago.
That prompted me to do some hunting and to remove one byte
from the program. The version now on the Web site will list
WDS data in "more info" correctly.
About asteroids: one problem I ran into with Guide 8 is
that there are about five times as many asteroids as there
were for the first Guide 7 disks. I had to do several things
to accommodate this. In Guide 7, for dates close to the
present, Guide used a 50-day spacing of epochs. I eliminated
that, so a 200-day spacing is used for all dates. (More on
this later.) I also made use of the fact that I had an extra
CD to put some of the more "distant" (in time) elements. But
even with this, I still had to reduce the range of dates
supplied to run from about 1960 to 2023.
Eventually, I may have a DVD to play with, and will be
able to greatly extend the range of elements. (Or, much more
likely to happen in the short term, I may provide numerical
integration in Guide so element sets for distant dates can be
generated.) In the meantime, we are stuck with a shorter
range of dates than I would like. (The data in the 1950s was
especially useful when dealing with DSS images from that era.
You could zoom in on such an image, spot an asteroid trail,
and usually identify it pretty quickly.)
That 200-day interval, meaning that 100 days of
perturbations can be ignored (instead of 25 days with a 50-day
interval), is a _big_ problem, especially for people working
with near-earth objects and high-precision applications such
as occultations. The errors scale quadratically, which means
that Guide's asteroid errors can now be 16 times greater than
they once were.
On the other hand, this just gives me one more reason to
include numerical integration. Do that, and the accuracy
reverses to become _better_ than it was in Guide 7, and the
range reverses: with some patience, you can generate elements
going back (or ahead) as far as you like. Once the initial
chaos of upgrading everybody dies down, that's my top priority.
-- Bill