Using SkyMap to improve success

Matson, Robert (ROBERT.D.MATSON@cpmx.saic.com)
Mon, 10 May 1999 11:01:09 -0700

Hi Jonathan,

> So, I went 3-6, 50.0%.  So, this year I have gone 5-24, 20.8%.
> And in 1998 (my first year of satellite observing), I went 41-128, 32.0%.
> And overall, I have gone 46-152, 30.3%.

If you switch to using SkyMap (assuming you have a PC) you should
be able to improve those percentages to better than 80%.  Having
solid, recognizable, stellar landmarks is the key to successful
satellite acquisition -- especially dim satellites.  One technique
I've used with great success is concentrating on the southern
part of the sky, say from azimuth 150 to 210.  Since the vast
majority of observable satellites/rocket bodies are in near polar
orbits, the southern and northern regions of the sky have the
greatest density of bright objects.  At this time of year (for those
in the northern hemisphere), the south is better than the north
due to the improved satellite phase angle.

That said, figure out what bright, recognizable constellations/stars
are midway up in the sky from az 150-210 from 1 to 2 hours after
sunset.  Right now that would be Corvus, Hydra, Leo and
Virgo.  Corvus and Leo are good targets because their constellations
are "tight enough" to be recognizable in binoculars, and the
stars that make them up are fairly bright.  Virgo is a little more
spread out, and I've always had difficulty using it as a reference.
It's a little better right now since Mars is close to Spica.  So you
might expand your search targets to include the Mars/Spica area.
The head of Hydra is also an excellent binocular target which I
have used with great success as a "staging area" for dim
satellites.  However, it is getting a bit far into the southwest now.
It's more useful in March and April.

Once you've settled on your target areas, you can use SkyMap
to zoom in on each of those regions and search for all satellites
passing through (over the space of an hour or two) which reach
a given magnitude (e.g. all satellites brighter than magnitude +5
passing through Corvus from 8:30pm to 10pm).  Pick out the
brightest ones, generate a hard copy, and you're ready to go!

For a typical night, I generate 5 or 6 hardcopies, one for each
region I'm interested in, with 5 to 8 satellite tracks on each.
(Much more than this and each page gets too cluttered).  Even
in my 5th mag (at best!) light-polluted skies, I routinely observe
20 or more satellites using this method in 90 minutes.  Quite
often I see 3 or 4 unexpected satellites in addition -- I draw a
line segment on my map showing the location and direction,
and jot down the time so that I can identify it later.

If you need help setting up SkyMap, I can give you some
pointers, as can many of Seesat-L's members.  With a
pair of binoculars and a little experience, you'll be acquiring
satellites that are less than a magnitude brighter than your
limiting magnitude:  6th or even 7th magnitude.

SkyMap can be found at the Visual Satellite Observer's
Home Page at:

ftp://ftp.satellite.eu.org/pub/sat/programs/ibmpc/sky63.zip

You'll also want sky62aux.zip, hip8.zip and hip8idx.zip, all at
the same location.

Best wishes,
Rob