Occultation by asteroid (429) Lotis
Observed: 8 Aug 2010
9 Aug 2010
updated 24 Sept 2010 (astronomical note), 24 Aug 2012
corrected 10 Apr 2017 (shadow size)
The minor planet 429 Lotis was observed occulting a 11.3 mag star.
The duration of the occultation is 1.8±0.4s.
The occultation of the 11.3 mag star UCAC2 31 081 100 by asteroid (429)
Lotis on 8 Aug 2010 was predicted by S. Preston and the information conveyed
over the Planoccult mailing list.
The observation was carried out with a 203mm f/6.3 SC telescope, a Clear
filter and a SBIG ST7E camera (KAF401E CCD). The conditions were fairly
good. The exposure was 60s long, starting at 23:06:50 UT: the telescope
tracked for 5s, then the drive was switched off by computer. The stars
then trailed for 55 s.
The computer clock was checked by listening to the Horloge Parlante (Observatoire
de Paris, France) and its precision is estimated to +/-0.5s. Futhermore,
the program for the image aquisition (MaximDL V4) records the time
to the nearest second.
A part of the resulting image is:
1: begin of the trail
2: begin of the disappearance
3: end of the disappearance
4: end of the trail.
My image is 0.294° and 765 pixels width. The trails are 607+/-1 pixels
long, start at 23:06:55 UT and lasts 55 s. The distance between 1 and
2 is 272+/-1.5 pixels, and between 2 and 4 335+/-2.5 pixels. The disappearance
is then at 23:16:19.6 UT +/-1.3s. The duration of the occultation is 19.5+/-4.0
pixels or 1.8+/-0.4s.
The occultation was also observed by C. Gualdoni, in Italy. A computation
of the chords by Euraster is HERE.
Telescope and camera configuration.
Computer and software configuration.