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Recent Occultations by Deimos and Ixion William H. Hanna Alice Springs, NT Australia IOTA 32 nd Annual Meeting 13 July 2014 College Park, MD USA

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Topics June was a very good month for firsts Observed an occultation by (II) Deimos Observed an occultation by (28978) Ixion Current setup Historical results

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The Deimos prediction came just in time I normally use Occult Watcher for long-term planning, but John Broughton, a prolific occultation observer based in Queensland, was examining upcoming predictions made by Occult 4 and found that a narrow (~12 km) predicted path for (II) Deimos, not currently listed in an OW feed, would pass just to the south of Alice Springs. John sent me an e-mail (giving barely four hours notice) and I immediately set up under ideal observing conditions. Observed a 1.5-second (of a possible 1.8-sec) occultation. The accuracy of the prediction was no doubt due in large part to the fact that the target star was in the Hipparcos catalog.

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The Deimos Prediction

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The result (at 30 fps)

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Short video of the Deimos occultation (note that Mars is greatly overexposed)

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Ixion prediction Credits: Rio Team & B. Sicardy

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Dim target star

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Gone

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The result (at 3 sec. per frame)

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The target star was a double Credit: Jose-Luis Ortiz

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Post-observation updated prediction

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My current setup 8 Meade LX90 f/10 with a Meade f/3.3 focal reducer at prime focus; polar mount Occasionally use a 14 Meade LX-200 GPS Point Grey Research Grasshopper EX GX-FW-28S5M Sony ICX674 2/3 1920x1440 14-bit CCD Astronomical Digital Video System (I am a beta tester) ADV Recorder v1.5.71 under Ubuntu Linux 12.04 LTS Fujitsu Lifebook E752 Laptop (Linux / Windows 7) with an IEEE 1394b 800 Mbps FireWire ExpressCard

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Recent observations are from my balcony

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on a pier relocated from the hillside

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Results of 135 attempts (as of 20140628) Observed an occultation: 11 Observed a miss: 76 No observation: 48 Weather: 33 Equipment problems: 4 Self-induced: 11 Target star too dim for my equipment: 4 Not set up in time: 3 Misidentified star field: 1 Software feature: 1 Personal reasons: 2

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Positives (52)Europa20120704 (I)Charon20120727 (using a 14) (134340)Pluto20120826 (using a 14) (92)Undina20130206 (790)Pretoria20130320 (578)Happelia20130506 (372)Palma20140217 (65)Cybele20140422 (II)Deimos20140617 (28978)Ixion20140624 (198)Ampella20140625