(54) Alexandra Occultation well-observed from Oklahoma, Texas, and Baja California on 2005 May 17

The actual path passed about 0.3 path-widths south of the predicted path.

I deployed and pre-pointed 4 small telescopes over an approximately 100-km stretch of Baja California Sur, but they were all too far north so that no occultation occurred at any of them.

Eleven other observers timed the occultation, covering the path well

New: 2006 March 8

The occultation of 8.4-mag. SAO 210301 = TYC 7902-01828-1 by 
(54) Alexandra on May 17th was the best-observed asteroidal 
occultation of the first half of 2005; not until December 3rd was 
there a better-observed event.  I traveled to southern Baja 
California, Mexico, with two 5-inch and two 4-inch Schmidt-
Cassigrain telescopes, PC164C video cameras, and camcorders for 
each.  With help from Kerry Coughlin and friends, we started at 
sunset to deploy them across the northern part of the predicted 
path.  Clouds from the Pacific covered Brian Westerland's site 
minutes before the occultation.  The actual path was south of the 
predicted one, causing my other stations that recorded the star to 
have no event, but they did show that no satellite of Alexandra 
covered the star there.  Observers farther south in the path covered 
the actual path well.  The Elliptical fit of the observations 
projected into the plane of the sky at Alexandra has the following 
parameters:

2a   160.3 +/-1.2 km    major axis
2b   134.8 +/-1.1 km    minor axis
PA    10.7 +/-1.7 deg.  position angle of major axis
Xo -1564.9 +/-0.4 km    X coordinate of center
Yo  6037.6 +/-0.4 km    Y coordinate of center

You can see the Alexandra sky plane view with the observations and 
the elliptical fit in this Power Point file.
The observations are listed here 
and the Occult .obs file is here.

David Dunham
e-mail home dunham@starpower.net; office david.dunham@jhuapl.edu