Lunar transit

Matson, Robert (ROBERT.D.MATSON@cpmx.saic.com)
Wed, 22 Jul 1998 16:02:09 -0700

Hi All,

Terry Pundiak asked if anyone has ever seen a satellite pass in front of
the moon --
confirmed with software.  The answer is a definite yes.  In fact, the
transit was
predicted in advance (using SkyMap) and then observed.  Seesat member
Jim
Varney posted an account of the observation to sci.astro.amateur:

> Tonight three observers from the Sacramento Valley Astronomical
Society
> -- Chris Hulbe, David Larzelere and Jim Varney -- went to a rural area
of
> Sacramento County, California (121.1 W, 38.6 N) to attempt to observe
Mir
> transit the 3 day old moon.  We were well armed for the event -- a
C-8,
> 20x80's, 10x50's, 6x50's, a camcorder and two 35mm cameras.
> 
> The predicted passage was Oct. 5, 1997 at 03:01:50 UT, with Skymap
> predicting a track from cusp to cusp right across the earthshine.  The
> moon was only 6.3 degrees above the western horizon.  The audio track
> from the camcorder gives a feel for what it was like:
> 
> 
> "I have Mir.  About 7 o'clock, a degree and a half."
> "Is it closing in?"
> "Closing in!  One degree, 7 o'clock!"
> "Almost ingress...!"
> "Ingress now!"
> "Wow..."
> "On the moon, on the moon!"
> "And... Egress!"
> "That was GREAT! Oh man!"  "Awesome!"
> 
> It took Mir 5.1 seconds to cross the lunar disk and was about 3rd or
4th
> magnitude.  Mir was dim because it was low in the sky and at long
range.
> 
> One of the things we remarked about was how accurate Skymap was.
Skymap
> just absolutely *nailed* the track right across the lunar disk.
Skymap
> called a cusp-to-cusp transit and that is just what we saw.  Hats off
to
> Rob Matson, author of Skymap -- outstanding job with Skymap!

I wholeheartedly encourage others to attempt to duplicate the
feat.  Timing is good right now since we're at new moon. --Rob