1 DATE : 12/DEC/2004 STAR : TYC 0144-01868-1 ASTEROID : (85) IO 2.OBSERVER: Name: Stefano SPOSETTI Address: CH-6525 Gnosca, Switzerland E-mail: stefanosposetti@freesurf.ch 3.OBSERVING STATION: Nearest city: CH-6500 Bellinzona Station: Gnosca Observatory Latitude: 46deg 13min 54sec (N) Longitude: 9deg 1min 30sec (E) Altitude: 260 m Single/Multiple: single 5.TELESCOPE: Type: Newtonian Aperture: 40cm Magnification: - Mount: equatorial Motor drive: yes 6.TIMING & RECORDING: Occultation recorded: POSITIVE Personal Equation Substracted: No Event Time in UT Code: HH:MM:SS.ss S.ss S 21:01:54,2 D 21:05:41.5 ± 1s R 21:05:55.5 ± 1s E 21:11:03,5 Duration of the occultation: 14,0 +- 0,2s Timekeeping: via Computer thru "Dimension4" software. Mode of recording: CCD drift-scan thru "Winscan 207" software. Device of recording: SBIG ST8 CCD 7.OBSERVING CONDITIONS: Atmospheric transparency: good Wind: no Star image stability: good Temperature: 0 deg C 8.ADDITIONAL COMMENTS: The accuracy of the absolute time measurement is +-1sec. The accuracy of the duration of the occultation is +- 0,2s While I'm quite confident of the accuracy of the duration of the occultation, it was quite difficult to determine the absolute timings ot the start and the end of the occultation. I can provide an selected image of the drift-scan.