Recent Positive Asteroid Occultations

Last Updated 2018 November.

Highlight: More than 50 reports in one year exceeded in 2018 October, and 8 positives, one was a double star anomaly.

Introduction:

My monitoring of an asteroid occultations was 1979 when predictions were being produced by Gordon Taylor. My first dissappearanec-reappearance, (130) Elektra, was recorded by video in 2010, a long wait. From 1990 I was becoming more active using low-light video with help from Andrew Elliott ( Assistant Director of the BAA Asteroid and Remote Planets Section 1995-2010). Up till 2003 I was using a Philips security camera module (25fps), sometimes with a Micro Channel Plate image intensifier. When the camera malfunctioned I obtianed the integrating WAT 120N+ and a manual sync VTI. I'm now exclusively a video observer using GPS as time source. This page summaries the positive events recorded since 2010.

Light curves obtained using TANGRA software by Hristo Pavlov
European results prepared by Eric Frappa: http://www.euraster.net/results/index.html

Bar Graph: The proportion in green are the +ve events.
Planetary satellites are in yellow: Titan/28Sgr in 1989 July, and Triton in 2017 Oct.

Diagrammatic Instrument Setup for video recorded events. Mobile recording equipment

Table:
Colour code to exposure times:: BLUE = with a 30cm F4 reflector Orange = with a 20cm F4 reflector

4 Positive events 2010:

Date	Body	Prediction	Link to report	Observed duration	Maximum duration	Magnitude Star / Astrd	Magnitude drop	Exposure	Light curve	Chords
Feb 20	(130) Elektra		Report	10.7	16.2 s	11.5 / 12.2	0.9	0.16		Chords
Mar 01	(532) Herculina		Report	5.8	23.0 s	10.0 / 8.9	0.33	0.64		One observer
Jun 05	(80) Sappho		Report	6.72	8.1 s	10.7 / 11.7	1.4	0.16		Chords
Oct 31	(213) Lilaea	Track Track-2	Report	7.1	5.9 s	10.8 / 12.8	2.2	0.64		One Observer

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5 Positive Events 2011:

Date	Body	Prediction	Link to report	Observed duration	Maximum duration	Magnitude Star / Astrd	Magnitude drop	Exposure	Light curve	Chords
Feb 15	(106) Dione		Report	21.76	36.6	12.7 / 12.3	0.6	0.32		Chords
May 03	(42) ISIS		Report	1.76	4.6 s	11.5 / 13.3	2.0	0.16		Chords
Sep 14	(48) Doris		Report	14.40	16.3 s	12.3 / 11.2	0.3	0.32		Chords
Nov 25	(83) Beartrix		Report	3.84	8.1 s	13.0 / 12.2	0.4	0.16		Chords
Dec 18	(1796) Riga		Report	3.44	8.6 s	11.9 / 16.0	4.1	0.16		Chords

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1 Positive Event 2012:

Date	Body	Prediction	Link to Report	Observed duration	Maximum duration	Magnitude Star / Astrd	Magnitude drop	Exposure	Light curve	Chords
Feb 23	(41) Daphne		Report	13.6	22.1 s	12.3 / 11.6	0.5	0.16
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Positive Events 2013 - NONE

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4 Positive Events 2014

Date	Body	Prediction	Link to Report	Observed duration	Maximum duration	Magnitude Star / Astrd	Magnitude drop	Exposure	Light curve	Chords
Jan 17	(56) Melete		Report	1.2	10.2 s	12.0 / 13.1	1.4	0.16
Apr 18	(386) Siegena		Report	13.8	14.6 s	12.6 / 13.0	(r) 0.9	0.16		One observer
Apr 18	(241) Germania		Report	NEG	8.5 s	11.9 / 13.7	2.1	0.16
Sept 02	(391) Ingeborg		-	2.2	2.7 s	12.4 / 12.6	0.9	0.16		Recorded by Adrian Jones

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2 Positive Events 2015:

Date	Body	Prediction	Link to Report	Observed duration	Maximum duration	Magnitude Star / Astrd	Magnitude drop	Exposure	Light curve	Chords
Sept 30	(275) Sapientia	observers	YouTube	14.7	18s	7.9 / 13.0	5.0	0.08s	Analysis	Euraster.net
Dec 20	(589) Croatia			6.2	7.3s	9.6 / 13.5	3.9	0.04s	Fame capture	Euraster.net

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4 Positive Events 2016:

Date	Body	Prediction	Link to Report	Observed duration	Maximum duration	Magnitude Star / Astrd	Magnitude drop	Exposure	Light curve	Notes
Feb 16	(423 ) Diotima			29.2	30	13.0 /11.9	0.5	0.16s		8" LXD55
May 23	(583) Klotilde			1.8	7.2	9.0 / 13.5	3.5	0.08s
Aug 09	(107) Camilla			18.9	22.9	14 / 12.8	0.4	0.08s
Oct 10	(268) Adorea			3.1	3.7	14 / 12.3	1.5	0.08s

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5 Positive Events 2017:

Date	Body	Prediction	Link to Report	Observed duration	Maximum duration	Magnitude Star / Astrd	Magnitude drop	Exposure	Light curve	Notes
Feb 07	(690) Wratislavia			8.4	14.7	12.8/13.1	0.7	0.32
Sep 24	(31) Euphrosyne			7.4	12.2	12.7/11.6	0.3	0.04
Oct 05	TRITON UTube			142	160	12.7/13.5	1.4v	0.64
Nov 19	(18) Melpomene			2.64	5	12 / 12.8	0.7v	0.04
Nov 28	(377) Campania			8.4	9	12 / 13	0.2v	0.04

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Positive Events 2018:

Date	Body	Prediction	Link to Report	Observed duration	Maximum duration	Magnitude Star / Astrd	Magnitude drop	Exposure	Light curve	Chords/Notes
April 21	(130) Elektra			16.4	20	11.6 / 12.9	1.5	0.04
May 05	(74) Galatea			7.42	9.5	12.9 / 13.4	0.8 r	0.08		OW observer chart Euraster.net chords
Sep 06	(238) Hypatia		Additonal Notes	12.0	13.4	11.2 / 11.9	1.2	0.16		Strong twilight (Sun at -7 deg). Combined Mag 10.7, Barlow x2 used. Frame
Sept 23	(2875)Largerkvist		Additional Note	0.60	1.0	11 / 16	0.4 Double Star Comes	0.08	Frame
Sept 26	(1573) Vaisala			0.68	1.0	12 / 13	2.2	0.08	Frame	Shift indicated - only one observtion in Moonlight
Oct 20	(27561) 2000 KJ1		Three observers got chords across this 20km object. The preliminary Occult profile is elongated.	2.12	2.0	13 / 17	4.0	0.16
Oct 29	(156) Xanthippe		The best UK event of 2018 with 14 observers positive following an alert to BAA members.	5.70	7.0	12 / 14.	2.3	0.04
Nov 02	(137) Maliboea		In strong twilight	4.64	6.0	12.6 / 13	0.5	0.16
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