+--------------------------------+ +--------------------------------+ ASTERIODAL OCCULTATION - REPORT FORM +--------------------------------+ +--------------------------------+ EAON & IOTA-ES EUROPEAN ASTEROIDAL OCCULTATION NETWORK INTERNATIONAL OCCULTATION TIMING ASSOCIATION EUROPEAN SECTION +--------------------------------+ +--------------------------------+ 1. DATE: 2010 Aug 28 STAR: TYC 5758-00120-1 ASTEROID: (1214) Richilde 2. OBSERVER Name: Stefano SPOSETTI Address: In Fun I Vign 7 - 6525 GNOSCA - Switzerland Email: stefanosposetti@ticino.com 3. OBSERVING STATION Nearest city: CH-6500 Bellinzona Longitude: 46deg 13min 53.2sec (N) Latitude: 9deg 1min 26.5sec (E) Altitude: 260m 4. TIMING OF EVENTS Occultation recorded: POSITIVE Type of event: "S"tart observation; "I"nterrupt-start; "D"isappearance; "B"link; "F"lash; "E"nd observation; "I"nterrupt-end; "R"eappearance; "O"ther (specify) Personal Equation Substracted: No Event Time (UTC) Accuracy + Comments code: HH:MM:SS.ss S.ss -S : 22:42:13 -D : 22:46:04.910 (+/- 0.01s) -R : 22:46:10.820 (+/- 0.02s) -E : 22:50:00 Duration: 5.91s (+/- 0.03s) 5. TELESCOPE Type: Schmidt-Cassegrain, Celestron 8-inch Aperture: 200mm Focal length: 800mm (with focal reducer) Magnification: FOV 30x20arcmin Mount: Equatorial Motor drive: Yes 6. TIMING & RECORDING Timekeeping: KIWI-OSD with GPS Garmin 18 LVC Sensor/Camera: Videocamera WAT-120N+, CCIR, 1/2" Sony CCD-Sensor ICX419ALL Videocamera settings: Shutter mode=1, Gain=HI , Gamma=LO Device of recording: Personal computer, TV-AV PCI-TV7130, S-video input, Virtualdub software, saved on Harddisk Mode of recording: Integration time=0.040s (25 Img/s), CCIR, Huffyuv Time insertion: KIWI-OSD 7. OBSERVING CONDITIONS Atmospheric transparency: good Wind: high altitude strong winds; some wind at the observatory Star image stability: poor; FWHM of stars about 10arcsec Minor Planet Visible: no 8. ADDITIONAL COMMENTS 8.1. The luminosity of the star was 10.0magV, 9.6magR. A quite bright target. The minimum integration time of 0.040s was therefore chosen. The Disappearance and Reappearance of the star was evident on the computer screen in the real time moment of the occultation. I warmly thank Gerhard Dangl for his careful analysis of the avi-file and for the evaluation of the Disappearance and Reappearance times of the star. 8.2. I observed the event simultaneously with my 400mm f/4 newtonian telescope equipped with CCD(SBIG ST8XME), located a couple of meters apart. Timekeeping was measured via Computer and Dimension4 software. The mode of recording of the CCD was drift-scan (Winscan 207 software) with an integration of 0.01s/line. The sampling was 1.2arcsec/pixel. The CCD trace suffered from severe turbulence. Stars show a FWHM of 10arcsec!An independent analysis was performed with this second experimental setup, using Iris software, and the results were: Disappearance: 22:46:05.00 +- 0.1s Reappearance: 22:46:10.87 +- 0.1s Duration: 5.87s +- 0.2s This result agrees with the previous evaluation with WAT-120N+ and GPS-time insertion. A jpg-image of the trace of the CCD scan is here http://web.ticino.com/sposetti/_1214__Richilde_28Aug2010_Sposetti_1.JPG The upper trace is only dark subtracted; the lower trace is electronically processed. The Disappearance of the star suffers of some turbulence, while the Reappearance is steeper. This event shows the superiority in time-precision of the video equipment and the GPS time insertion. The quite high brightness of the star and the quite high magnitude-drop favoured the video registration versus the CCD's use. 8.3. My location was inside the 1sigma band, north of the predicted ground path, and was given a 34% of chance of positive detection.