A 6 second occultation was recorded by David Dunham, using an unattended video recording setup.
3 misses were recorded for this event.
View the IOTA update.
Observers: 1(M) S Kerr,Rockhampton, Queensland, Australia 2 D Dunham,Aileron, NT, Australia 3(M) D Dunham,Taylor Creek, NT, Australia 4(M) R Williamson,Connellon, NT, Australia 5(P) Prediction- IOTA Feed
The circle above is plotted at the expected 169 km diameter of Bertholda. As can be clearly seen in the graphics above, it is not possible to fit a 169km circle to the positive observation without overlapping reported misses. It should be noted that of the chords reported here, only Steve's (chord 1) was recorded with a tracking telescope - all of the others are prepointed and as such only cover the event for a short duration. However, the event time reported by David for his Aileron site does not significantly differ from the prediction and there is no reason to suspect that any of the other sites would have missed the event assuming they were aimed correctly (and the reports state that the correct field was imaged at the correct times).
(420) Bertholda has been extensively observed by occultation before with a very detailed profile recorded on 2003 August 26. The profile is plotted below. While this observation is dominated by visual observers, it clearly shows that (420) Bertholda is an oblong object.
If the dimensions from that observation are applied to the current observation, it can be shown that the miss observations can be accomodated. While it fits more easily on the northern side of the positive observation, it is possible that it could be on the southern side.
David and Joan Dunham had depoloyed a number of additional unattended stations along the Stuart Highway but suffered an unusual number of failures with equipment as well as interference - presumably from animals! It's dangerous in the Australian outback at night!
Observation details for MP ( 420 ) Bertholda By Star TYC 6268-01114-1 On 2015-07-31 at 10:20:17.0 _______________________________ Observer Stephen Kerr Location Rockhampton, Queensland, Australia Longitude +150:30 Latitude -23:16 Altitude 50 m Datum Other Telescope SCT including Cass and Mak Aperture 30 cm Seeing Slight flickering Clear Camera Type Watec 120N+ PAL/CCIR Camera Delay Timing GPS - time inserted Video with frame analysis Missed Comments: Report prepopulated by IOTA Reporting Add-in for OW ver.1.8 _______________________________ Observer David and Joan Dunham Location Aileron, NT, Australia Longitude +133:22 Latitude -22:42 Altitude 662 m Datum WGS84 Telescope Refractor Aperture 8 cm Seeing Steady Clear Camera Type Other - List in Comments NTSC/EIA Camera Delay Timing GPS - other linking Video, photo or photoelectric Disappearance 10:22:57.00 Reappearance 10:23:03.00 Comments: Remote unattended pre-pointed station using a KPC-650-BH? (NTSC) camera, "Supercircuits PC164C-EX2". Recorded with Canon ZR60 #37. Used a paver and paver mount to pre-point the scope the night before. Left the paver in place, returned with scope & mount July 31. -109km(s) of pred. center. IOTA-VTI pre-cal 5:05UT (event -5.3h), post-cal 14:00UT (event +3.6h); .avi files being uploaded to IOTA Dropbox folder. _______________________________ Observer David and Joan Dunham Location Taylor Creek, NT, Australia Longitude +134:09 Latitude -21:08 Altitude 417 m Datum WGS84 Telescope Refractor Aperture 12 cm Seeing Steady Clear Camera Type Other - List in Comments NTSC/EIA Camera Delay Timing GPS - time inserted Video, photo or photoelectric Missed Comments: Remote unattended pre-pointed station using a KPC-650-BH? (NTSC) camera, "Supercircuits PC164C-EX2". Pre-pointed at 9:02 UT (event -1.4h) and recorder left recording. _______________________________ Observer Richard Williamson Location Connellon, NT, Australia Longitude +133:54 Latitude -23:46 Altitude 550 m Datum WGS84 Telescope SCT including Cass and Mak Aperture 20 cm Seeing Steady Clear Camera Type Watec 120N+ PAL/CCIR Camera Delay Timing GPS - time inserted Video, photo or photoelectric Missed Comments: No integration was used. Pre-pointed before the occultation.