Daytime Iridium seen / Automating Iridflar

Craig Cholar (3432P@VM1.CC.NPS.NAVY.MIL)
Mon, 01 Dec 97 23:20:41 PST

I saw my first daytime Iridium flare today.  The method of staking
out sight lines the night before, using landmarks such as tree tops,
really works.  Having my backyard conveniently on the flare centerline
helped a bit, too.  :-)

A slightly modified version of the Iridflar output:

Ir   Date      Time       Azm El  Range SunEl M FlrAng Mag SMag
18 97-12-01 16:22:46 PST  263 26  1503   4.3  F  0.01 -3.8 -6.1

I decided to wimp out and use 7x50's, but I think I could have
seen the flare without them.  I'll have to try more of these
daytime flares.  The nighttime ones are getting pretty scarce,
at least at my latitude.

If you don't use Rob Matson's Iridflar, you can stop reading now.

I run Iridium flare predictions for several locations in the
San Francisco bay area, and if I see a good flare coming up I
post a heads-up to a local astronomy discussion group.  A good
portion of the subscribers like watching the flares, but use
platforms such as Macs or Unix systems which currently lack an
Iridium flare prediction program, so I run predictions for them.
To make it easier to run batches of predictions, I use an MS-DOS BAT
file and a text editor to do all of the following in a WIN 95 DOS
session in background:

1) Edit each Iridflar config file (one for each location) using
   an automated macro to insert today's date and time.
2) Invoke a DOS TSR program to 'stuff' the keyboard with the
   appropriate number of carriage returns, and an 'n' to supply
   the 'Another calculation?' prompt.
3) Run Iridflar, after stuffing the keyboard buffer.
4) Repeat steps 1-3 for each location.  I do predictions for six
   locations, and the BAT file does all of them for me each time it's
5) Use the DOS copy command to create a single Iridflar output file.
6) Edit the output file with a text editor macro to create an HTML
   document, converting the lat/long to URL's to link to both the
   Tiger Map Server (great detail, but slow) and the Xerox Parc
   map server (not much detail, but faster).  I've already posted
   an earlier version of this macro to Seesat-L.
7) Issue a 'START C:\IRIDMAP.HTM' command as the last step.  This
   activates my browser and brings up the Iridflar web page I just
   created.  I can then click on the flares that look good, see
   the locations of the centerlines displayed on the map, and send
   off predictions saying that cities a, b, c, etc. are going to be
   on the centerline.

The keyboard stuffer program is available at
if you do a keyword search for '' in the DOS category.
Here's an example of how I use it, just before calling Iridflar:

stuffit +0 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13
         P30,0,160,"calculation?" +1 13 >nul
The above two lines are broken up here, but are one continuous line
in the BAT file.  The +0 clears the keyboard buffer.  Each 13 represents
a carriage return in hex, and the P30... parameters tell Stuffit to
wait for a prompt with "calculation?" in it, and press enter when it
shows up, after pausing for a second.

The text editor macros I have won't work unless you have the Kedit
editor, a commercial (not shareware) product.

 Craig Cholar    3432P@VM1.CC.NPS.NAVY.MIL
 Marina, California
 36 41 10.3N,  121 48 17.9W    (36.6862, -121.8050)      UTC -8