2003 Jan. Bathilde Occ'n - 2 remote videos & Maryland expedition results

New: 2003 Feb. 21

     The January 11th occultation of SAO 117679 by (441) Bathilde
was the first one where unattended telescopes at two sites
successfully recorded the target star during the appulse.  You know
about Roger Venable's successful remote recording of the
occultation, while several miles away he also timed the occultation
visually with a pair of binoculars, the first remote video/attended
visual observation of an asteroidal occultation (in contrast, for the
two other remote successes, mine with 9 Metis in Sept. 2001 and
Steve Preston's with the occultation of 26 Gem by 701 Oriola in
April 2002, video recordings were made at all stations).  On January
11th, I also ran a remote video station, and it recorded the target
star during the minute surrounding the closest approach, but that
station was outside the occultation path and had no occultation.

     I obtained permission from a homeowner on the north side of
Glennville, Georgia, to set up a C-8 in his yard, about 100 feet
east of the north-south highway US301 and overlooking a large dark
field.  Alin Tolea and I set up the telescope with f/3.3 focal
reducing lens and Watec 902H camera about 2 hours before the
appulse, and at just the right time, we aimed the telescope at a
distinctive group of stars near Procyon, aimed at the same
declination as the target star but two hours of R.A. less.  That is,
it was pointed at the altitude and azimuth that the target star
would have at the time of the appulse so that we would not have to
worry about the accuracy of a clock drive; the telescope's clamps
were locked and it was not driven.  Then several miles south of
Glennville, we couldn't find any houses with awake occupants near
US301, but we found a small deserted building and set up a
C-5 at the edge of woods near it, and focused the video and aligned
the finder scope, using another f/3.3 reducer and PC-164C camera.
Then we drove several miles north of Glennville, where Alin and Magda
Tolea stayed, setting up their 4-inch refractor with another PC-164C
and a reducing lens.  On the way back to the C-5, I stopped at the
C-8, and 30 minutes before the occultation I started the video
recording, then went to the C-5, got the video running there, and
located the target star a few minutes before the occultation.  In
summary, our expedition from Maryland obtained the following
negative observations at 3 sites near US301 in Georgia:

Distance  (determined with W. Warren's Magellan GPS)
from         W.
center,  Longitude  Latitude  Height   Location       Observer
km      deg.  '    deg.  ,     feet
25N      81 54.562 +32 03.576  150  near Midway      Alin Tolea
14N      81 55.396 +31 57.070  156  n. Glennville    none (remote)
 3N      81 55.840 +31 51.250   39  s. of Glennville David Dunham

The target star crossed the video field at the remote site from
3h 54m 10s to 3h 55m 57s UTC.  The closest approach time there was
3h 55.5m, but the target star arrived in the field a little earlier
(that is, the observation interval was not symmetric about the
closest approach time) because we did not take into account the
difference between solar and sidereal rates.

David Dunham