1	Practical NEO work where amateurs can still make a contribution Peter Birtwhistle Great Shefford Observatory www.birtwhistle.org Summer Meeting, Basingstoke 19th July 2008
2	Agenda Minor Planets & the Near Earth Objects (NEOs) Equipment Basic techniques Positional work – Astrometry Photometry Discovery Very fast moving objects (VFMOs)
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4	Equipment for NEO work Ideally… 25cm / 10” or bigger telescope CCD (essential for real-time work) GoTo mount and some degree of automation in telescope positioning and image taking ‘Ready to go’ (permanently polar-aligned mount) … Images need to be measured and results sent to the Minor Planet Center (MPC) the same night
5	Great Shefford Observatory
6	Great Shefford Observatory
7	Basic Techniques
8	Track & Stack Example: 2004 TD₁₈21/22 October 2004 120 x 30s exposures = 1 hour total exposure
9	Stacking with the right tracking…
10	Stacking with the right tracking…
11	Stacking with the right tracking…
12	Positional work
13	Positional work New discoveries from NEO Confirmation Page (NEOCP) Unconfirmed, with potentially large uncertainties Follow-up of confirmed discoveries NEOs during their discovery apparition NEOs at their second return Recovery , with potentially large uncertainties – line of variation Follow-up after recovery NEOs at further returns
14	Confirming NEOCP FMOs (Fast Moving Objects!) Example: AO18761 discovered by LINEAR 2004 May 24 05:00 UT at mag +18.8, motion 34”/min Added to NEOCP 14 hours later at 18:48 UT By 2004 21:00 UT mag +19.3 motion 24”/min Prediction by the Minor Planet Center showing area of sky where object is likely to be Position (0,0) is the ‘nominal’ position, the most likely location to find the object. Each dot represents a ‘variant’ orbit.
15	Confirming NEOCP FMOs
16	New discovery confirmation Discovered by LINEAR 06:58 UT 11 July 2005 Added to the NEOCP 40 hours later(!) Magnitude 16-17 and moving at 50”/min By then uncertainty area 9° x 0.3° and growing fast Telescope/CCD field of view 18’x18’ – a big search required…
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18	Example AU52949 = 2005 NG₅₆
19	2007 RS₁
20	2007 RS₁
21	2007 RS₁
22	2007 RS₁
23	2007 RS₁
24	2007 RS₁
25	2007 RS₁
26	2007 RS₁
27	2007 RS₁
28	2007 RS₁
29	2007 RS₁
30	2007 RS₁
31	2006 RH₁₂₀= 6R10DB9
32	2006 RH₁₂₀= 6R10DB9
33	Recovery of NEOs at 2^nd return Uncertainties in old orbits mainly in T (Perihelion time) 2005 BT₁ 2007 DA
34	Recovery of NEOs at 2^nd return
35	Recovery of 2005 BT₁
36	Recovery of 2005 BT₁
37	Recovery of 2005 BT₁
38	Recovery of 2005 BT₁
39	Recovery of 2007 DA
40	Recovery of 2007 DA
41	Recovery of 2007 DA
42	Photometry
43	(54509) YORP = 2000 PH₅ This naming collectively honors Ivan O. Yarkovsky, John A. O'Keefe, V. V. Radzievskij and Stephen J. Paddack, who were instrumental to the realization that radiation torques due to sunlight can affect the spin states of minor planets. Data on this object provided the first direct observational evidence for the YORP effect.
44	(54509) YORP = 2000 PH₅
45	(54509) YORP = 2000 PH₅
46	(54509) YORP = 2000 PH₅
47	(54509) YORP = 2000 PH₅
48	2008 JL₂₄ Discovered by LINEAR on 11 May 2008 at magnitude +17 and moving South-East at 46"/min in the evening sky in Virgo, about midway between Arcturus and Spica…
49	2008 JL₂₄
50	2008 JL₂₄
51	2008 JL₂₄
52	2008 JL₂₄ 79 x 6 second exposures taken over a period of 13 min 43 sec 4 complete rotations Amplitude 0.7 magnitudes
53	2008 JL₂₄
54	2008 JL₂₄
55	2008 JL₂₄
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57	Minor Planet Discoveries Problems for small telescopes discovering faint NEOs …and it needs plenty of luck to discover a bright NEO… Main belt “discoveries” have often been observed before… Tying up possibly many one-nighters Follow-up at other oppositions to get numbered
58	Checking for moving objects
59	Checking for moving objects
60	Very Fast Moving Objects (VFMOs)
61	Observing known VFMOs Normally very small, only bright enough to be discovered when already close to Earth Often very little lead time before closest approach Watch NEOCP for telltale signs – fast acceleration within 24 hours Try to catch as early as possible on night of close approach – uncertainties grow quickly
62	2005 UW₅– a VFMO
63	A VFMO NEO discovery?
64	Discovering VFMOs VFMOs find you, you don’t find them! When to chase and when to ignore?
65	Discovering VFMOs VFMOs find you, you don’t find them… When to chase and when to ignore?
66	Discovering VFMOs Must notice in real-time Reduce exposure length and shift telescope to keep up for first few minutes or longer if possible Measure positions, preferably not ends of trails Use Sat_ID for quick ID of known ART SATs Use FindOrb to work out orbit (or simple extrapolation) and extend ephemeris to keep following… Try to determine if artificial satellite or NEO?!
67	VFMO 2007 EH
68	VFMO 2007 EH
69	Phase Effect
70	2007 EH: 10-11 March 2007
71	2007 EH: 10-11 March 2007
72	2007 EH at closest approach
73	Practical NEO work where amateurs can still make a contribution Peter Birtwhistle Great Shefford Observatory www.birtwhistle.org Summer Meeting, Basingstoke 19th July 2008