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ASTERIODAL OCCULTATION - REPORT FORM

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EAON & IOTA-ES

EUROPEAN ASTEROIDAL OCCULTATION NETWORK

INTERNATIONAL OCCULTATION TIMING ASSOCIATION EUROPEAN SECTION

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1. DATE: 17 Mar 2017
STAR: 4U 423-53132
ASTEROID: (25846) 2000 EF93

2. OBSERVER
Name: Stefano SPOSETTI
Address: 6525 GNOSCA - Switzerland
Email: stefanosposetti@ticino.com

3. OBSERVING STATION
Nearest city: CH-6525 Gnosca
Longitude: 9d 1m 26.5s (E)
Latitude: 46d 13m 53.2s (N)
Altitude: 260m
(WGS84)

4. TIMING OF EVENTS
Occultation recorded: UNCERTAIN
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.sss

-S : 19:07:04
-D : 19:11:17.56 ± 0.08 s
-R : 19:11:17.88 ± 0.08 s
-E : 19:16:43

Duration: 0.32 s ± 0.16 s

TELESCOPE
-Type: Schmidt-Cassegrain, Celestron 11-inch
-Aperture: 280 mm
-Focal length: 930 mm (with focal reducer)
-FOV: about 23x18 arcmin
-Mount: Equatorial
-Motor drive: Yes

6. TIMING & RECORDING
Sensor/Camera: Videocamera WAT-910HX, CCIR, 1/2", ICX429ALL sensor
Videocamera settings: Shutter = x8; Gain = 41/41; Gamma = 1.00
Device of recording: Personal computer, Imaging Source DFG/SV1 PCI grabber, composite input, Virtualdub software, saved as uncompressed file on Harddisk
Timekeeping: GPS 1PPS (US Global Sat EM-406A)
Time insertion device: IOTA-VTI, v.1.1.42
Integration time: 0.160 s

7. OBSERVING CONDITIONS
Atmospheric transparency: good
Wind: no
Star image stability: fair
Minor Planet Visible: -

8. ADDITIONAL COMMENTS
-Target position at: azimut = 137 deg; elevation = 29 deg
-Moonlight: none

Accordingly to Occultwatcher's prediction (UKOCL feed):
-Rank: 9
-Probability: 3.8 %
-Lightdrop: 4.6 mag
-Max duration: 1.3 s
-Event time: 19:12:06 UT
-Error in time: 9 s

-Tangra v. 3.6.0 was used to generate the lightcurve (aperture photometry, average background).
-A correction of - 0.100 s was applied because of the use of an integration camera.
-Because of a lightdrop to zero during 2 integration frames, and a very early anticipation of 49 s relative to the predicted event time, the observation has to be judged as UNCERTAIN.

-A lightcurve can be seen here:
http://sposetti.ch/wp-content/uploads/2014/09/2017_03_17_2000EF93.png