star charts while observing

Ryan Rudnicki (RR03@academia.swt.edu)
Thu, 08 Dec 1994 13:37:02 -0600 (CST)

Folks:

I forward the following message for two reasons.  First, to the beginner
satellite watchers the following information may be of interest.
Second, I wonder if the seasoned satellite observers use the star map
technology Dave refers to toward the end of his post?  

Until now, folks take the predicted positions of satellites generated 
by a program like Mike McCants' Quicksat and transfer RA & declination manually
to a star chart for use in the field when observing the actual satellite. As far
as I know, folks have been using traditional star atlases. Is there anyone
out there who has used a digital star atlas/program and printed out an
evening's worth of maps on their laser printer? Afterwards the maps can
be annotated and filed or discarded (recycled).

If so, which star map program is best or the most widely used? Has an
interface been written between the satellite prediction program (Quicksat,
Traksat, ...) and the star chart program so the process from prediction to
map production is automated? If so, between which prediction/star atlas
programs? Has anyone used the SkyMap program mention by DM below?  The
only SkyMap I know of was written by a fellow in England and can be downloaded
from a machine in the UK. The SkyMap program to which DM refers was apparently 
written by a fellow in San Diego, California and I'm not familiar with it at
all.

Ryan Rudnicki
rr03@academia.swt.edu


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>Date: Tue, 06 Dec 1994 20:34:41 -0600 (CST)
>From: Dave Mullenix <djmullen@facstaff.wisc.edu>
>Subject: Mir is coming for Christmas!
>To: amsat-bb@amsat.org

>Just a heads up:

>Mir begins a series of visible evening passes over North America this
>month.  Most of us will have some excellent evening passes just
>before and after Christmas.  Mir, the Space Shuttle and a couple of
>the "secret" recon satellites are the brightest objects in orbit.  Mir
>looks like a very bright star moving across the sky.  A typical pass
>is six to eight minutes long, from when you first see it until it
>disappears into the earth's shadow or fades out near the horizon.

>I've found that people are VERY interested in knowing when and where
>to look to actually see Mir.  I usually use tracking programs to look
>for good passes and plot them on star maps.  Then I announce the
>times and where to look for the best passes on local 2-meter nets.
>We never fail to have several dozen people monitoring the repeater
>when pass time comes and everybody has a great time watching it.
>(And you can occasionally hear Mir on 145.55 while you watch it go
>over - an absolutely delightful experience!) You can hardly find a
>better way to introduce hams to hamsats.

>If you'd like to try this, you'll need a tracking program that can
>calculate VISIBLE passes.  To see a satellite, it not only has to be
>above your horizon, but the sun has to be down at your location while
>the satellite is still in sunlight above you.  Most ham oriented
>tracking software only tells you when the satellite is above the
>horizon. 

>I normally use TrakSat 2.80 for most of my visual work.  It shows
>orbits on a world map or on a star map.  It can also output the data
>in text form (altitude, azimuth, range, etc) to a disk file.  TrakSat
>2.80 will work on XTs with Hercules monitors or better and if you
>have a slow computer you can let it chug away overnight, searching 30
>days ahead and saving the results in a disk file you can read in the
>morning.

>Once you've found a likely pass, it helps to plot Mir's path on a sky
>map.  This lets you tell people things like, "Mir will pass through
>the bowl of the Big Dipper at 7:13 pm", which helps people find it.

>If you decide to do this, I HIGHLY suggest you calculate and watch a
>few passes to get the hang of it before announcing it on the air.
>There are some pitfalls, such as a pass that looks great on paper,
>except that it's across the western sky and you're looking at the
>shadowed side of the space station, which makes it very dim and hard
>to see.  Another problem is that Mir occasionally reboosts - fires
>its rockets to raise its orbit back up to where it should be.  When
>it does this, of course, your predictions are toast.

>Another program is even better for finding visual passes if you can
>figure out its arcane menu structure.  This is SkyMap and it plots
>"near publication quality" star maps and then plots the satellite's
>path across them.  Once you figure out how to tell it to do so, that
>is.  SkyMap also has a great search routine that finds future visible
>passes very quickly - again, if you can figure out how to do it.

>Both programs are widely available on BBSes and can be found on the
>Clear Skies BBS in Madison, WI at (608) 249-7130.  I've also just
>uploaded them to oak.oakland.edu.  Look for these file names:

>TrakSat: TRAK280A.ZIP, TRAK280B.ZIP
>SkyMap:  SKY57A.ZIP, SKY57B.ZIP, SKY57C.ZIP

>If anybody has any questions, I'd be happy to help.  Email me at
>djmullen@facstaff.wisc.edu.

>Thanks and Merry Xmas,
>Dave, N9LTD