Occultation of SAO 134182
by minor planet (663) Gerlinde - 2003, Feb 13/14
In the night of
February 13/14, 2003, the bright 9.0 mag star TYC
4814-00668-1 = SAO 134182 was predicted to be
occulted by minor planet (663) Gerlinde, a 104 km
diameter body. The calculated occultation path was
extremely favourable for Belgium (see figure below).
The event was predicted to happen around 19h48m UT.
Manek, Czech Astronomical Society
Sky conditions were
quite good over the whole of Belgium. Except
for the strong moonlight, the sky was clear and
rather stable (but freezing cold). At the start of
the evening, it became evident that the occultation
was receiving a lot of attention from Belgian
amateur astronomers, looking at the number of emails
appearing on the "bulletin board" of our
national astronomical association VVS.
I decided to attempt "high-speed" CCD
photometry to register the 4.7 magnitude drop that
would last for about 13.4 seconds. I used an SBIG
ST-7 CCD on my 0.35-m f/6.3 telescope, and selected
a small CCD image field to considerably speed up the
download time. I exposed each CCD image for 0.8
seconds. Add to this a download time of about 1.2
seconds, and I was able to monitor the occultation
with a "time resolution" of about 2
seconds. Next to SAO 134182, I made sure to include
1 additional comparison star, that I would use to
measure the magnitude drop.
I started my CCD
observations around 19h40m UT, and continued till
about 20h00m UT. The resulting light curve is
depicted below, and clearly illustrates that no
occultation was measured with a duration > 2
seconds. The "noise" on the light curve is
due to the short exposure time and the faint
observers, spread over Belgium, also reported
negative observations. This, by itself, is valuable
from a scientific point of view, but I would of
course have preferred to actually measure the
One final remark :
almost 10 years ago, on January 12th, 1993 to be
precisely, I made a successful visual observation of
the occultation of PPM 154323 (a mag 9.2 star) by
minor planet 1330 Spiridonia (Stamm, J. 1996.
Reports of asteroidal appulses and occultations.
Occultation Newsletter 6: 221-224). This was the
first time such an event was observed from Belgium.