Report:
DATE:
2009-08-03
STAR:
45 Cap
(5.96m)
PLANETARY BODY: Planet Jupiter
OBSERVER:
Name: Marc
DELCROIX
E-mail: delcroix.marc@free.fr
Address: 2, rue de l'Ardèche
31170 TOURNEFEUILLE, FRANCE
OBSERVING
STATION: Nearest city: Tournefeuille (31 - France)
Station: Marc Delcroix's Home
Latitude: N 43 34 59.05 (Google Earth)
Longitude: E 01 19 34.43 (Google Earth)
Altitude: 163 m (Google Earth)
Single station
TIMING
OF EVENTS: OCCULTATION RECORDED: POSITIVE
Type of event
Start observation
Interrupt-start Disappearance
Blink Flash
End observation
Jnterrupt-end
Reappearance
Other (specify)
Event Time (UT)
P.E. Acc.
Code HH MM SS.ss
S.ss S.ss
S -
22:50:01.3217
0.008 :
"H" - 22:59:04.8
0.1 : Half nominal stellar intensity
E -
23:04:04.8726 0.008 :
TELESCOPE:
Type:
REFLECTOR
Aperture: 254 mm Magnification: F/11
Mount:
EQUATORIAL Motor drive: YES
TIMING & RECORDING:
Time source: NTP server ntp2.oma.be, synchronisation with
BeeperSync running
Sensor: CCD (Lumenera SKYnyx 2-0M, 0.4s individual
exposures, Custom Scientific 890nm(18nm) methane filter)
Recording: PC (Lucam Recorder)
OBSERVING CONDITIONS:
Atmospheric transparency: 4/5
Wind: none
Temperature: ~22°C
Star image
stability:
4/10 Minor planet visible:
yes
Observer analysis results:
-
half nominal stellar intensity estimated at 22:59:05.8 UTC, computed
around 22:58:42 UTC, C-O=-24s
computed
time derived from
-estimated predicted time for star at 1bar level in Jupiter
atmosphere for observing location between Pic du Midi and Paris
(France) - see http://jupiter2009.iota-es.de
-estimated predicted time for half nominal stellar intensity
(at 2µbar level in Jupiter atmosphere) = time at 1bar level -36s
Animation:
Lightcurves:
6 minutes light curve around half nominal stellar intensity:
2 minutes light curve around half nominal stellar intensity:
Data:
-
2000 0.4s frames, from 22:50:01.3217 UTC to 23:04:04.8726 UTC
- PC time synchronized with Beeper Sync, estimated time keeping
precision below 8ms
Data
processing information:
-
Individual frames timestamp at mid of individual exposure, taking into
account delay between end of frame and time of recording on PC as delay
between current and previous frame minus individual exposure time
-
Dark substraction
- Exposures aligned
- Photometry performed:
- with fixed circle including star and part of Jupiter limb
(where
immersion occured), excluding major Jupiter details in methan (Great
Red Spot) rotating along capture
- on Io satellite with same radius circle
- Intensity calibration:
- usage of factor=average Io
Intensity/Current frame Io intensity for each frame to
compensate for turbulence/transparency
- substraction of linear (y=ax+b)
least squared regression performed on
intensity before start of occultation, to compensate for sky background
evolution
-
Half nominal stellar intensity estimation performed on 19 frames
sliding average:
- by calculating half nominal stellar
intensity as [(calibrated
intensity averaged before immersion)+(calibrated intensity averaged
after immersion)]/2
- find the time for which
this intensity is reached on the main decreasing light curve (between
22:58:48 UTC and 22:59:13 UTC)
- Method 1: intersection of light curve with line average of linear least squared regression of intensity before immersion, and wh
Marc
Delcroix
2009-08-07, updated 2009-08-09