Orbital binaries/Genesis

Bill J Gray Mar 30, 2002

Larry, about "Genesis": this is yet another bug. Genesis is actually
a probe, one being sent out to the L1 point between the Earth and Sun.
Guide should not be treating it as if it were a comet (the Galileo probe
can also appear in that list, and shouldn't; probes in heliocentric orbit,
such as Cassini and the Voyagers and Pioneers, are okay.) This will
be fixed in the next update I post.

The fact that Guide can show such objects is probably news to
everybody. I did some work on it a while ago, but it's not exactly
perfect yet. It sort of developed from some attempts I made to get
orbital elements for "historical" (and some current) spacecraft, as
described at

http://www.projectpluto.com/probes.htm

I do want to complete display of probes (and, especially, display
of viewpoints _from_ probes; seeing the views from Cassini and
Galileo as they zip around the moons of Saturn and Jupiter is quite
impressive). I put it on the back burner in the rush to get other things
done for Guide 8.

On another topic: I can now state confidently that orbital binaries
will be handled properly in the next update. Last night, I rigged
Guide to show "more info" about them, including ephemerides such
as (for Sirius and Sirius B/"the Pup"):

Year PA Sep Year PA Sep Year PA Sep
2002.0 130.5 5.40 2007.0 101.9 7.62 2012.0 85.7 9.49
2003.0 123.0 5.85 2008.0 98.0 8.04 2013.0 83.2 9.80
2004.0 116.6 6.30 2009.0 94.5 8.44 2014.0 80.8 10.07
2005.0 111.0 6.75 2010.0 91.3 8.81 2015.0 78.5 10.32
2006.0 106.2 7.19 2011.0 88.4 9.16 2016.0 76.3 10.55

(The above may only make sense with a fixed-size font.) So
the basic functions are in place; it won't take much more to get
Guide to show such stars properly positioned when you zoom in
on them.

-- Bill