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Occultation observations from around the world Jan 2011 to Jun 2012. Dave Herald. Part 1. Lunar Occultations. Summary of observations Jan. 2011 – Jun. 2012. # Observations by region. Nth America 357 Australasia 1201 Japan 928 Europe 2082 MiddleEast 88. # Reported Grazes by region.
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Occultation observations from around the worldJan 2011 to Jun 2012 Dave Herald
Part 1 Lunar Occultations Summary of observations Jan. 2011 – Jun. 2012
# Observations by region • Nth America 357 • Australasia 1201 • Japan 928 • Europe 2082 • MiddleEast 88
# Reported Grazes by region • Nth America 2 • Australasia 10 • Japan 12 • Europe 10 • Middle East 2 • Total 36
Grazes with 5 or more observers 2011 Apr 23 – Australia (5) 2011 Sep 17 – Australia (6) 2011 Aug 24 – Europe (5) 2012 Jan 29 – Japan (6)
Grazes by number of events (>10) • Date # events Region (# observers) • 2011 Sep 17 42 Australia (5) • 2011 Apr 8 36 Australia (3) • 2011 Nov 3 36 Japan (4) • 2011 Aug 22 34 USA (2) • 2011 Aug 24 31 Europe (5) • 2011 Oct 3 30 Japan (3) • 2012 Jan 29 28 Japan (6) • 2011 Mar 13 27 Japan (2) • 2011 Mar 11 20 Europe (2) • 2011 Dec 10 16 Japan (2) • 2012 Feb 4 14 Japan (1) • 2012 Apr 1 14 USA (1) • 2012 Apr 29 13 Europe (1) • 2011 May 7 12 Japan (1) • 2011 Jun 23 12 Australia (1) • 2012 Jan 29 12 Europe (1)
Double star observations Reports collected and analysed by Brian Loader, New Zealand • # positive measures 94 • # doubtful doubles 30 • # definite ‘not double’ 58 • # wide doubles 22
Some double star solutions R3287 S97067 S96610 S76152
Part 2 Asteroidal Occultations Summary of the best events Jan 2011 – June 2012
Number of successful events by region, and max # sites: 2011/01 2012/06 • Australasia 51 + 29 (7 sites) • Europe 51 + 31 (19 sites) • Japan 25 + 21 (25 sites) • US 76 + 27 (57 sites) Japan has a much smaller land area than the other regions; Australasia has a much smaller population
Double stars discovered in asteroidal occultations • New double stars can be discovered in an asteroidal occultation • Separations are usually in the range 0.1” to 0.001” • If several observers, the uncertainty in separation can be less than 1 milli-arcsecond
7 double stars discovered since Jan 2011 Star number Sep (mas) P.A. Date Asteroid HIP46249 6.5 ± 1.1 50.2 ±12.2 2011 Jan 24 160 Una 1866-01091-1u 12.5 34.0 2011 Sep 13 177 Irma 2849-00430-1 0.6 68.4 ± 3.3 2012 Jan 13 759 Vinifera HIP41337 93.0 93.0 2012 Jan 19 911 Agamemnon 1865-01119-1 23.0 99.0 2012 Feb 18 177 Irma 0126-00781-1 3.5 ± 1.0 38.3 ±14.6 2012 Mar 11 57 Mnemosyne 6273-01033-1 36.0 151.0 2012 Mar 20 44 Nysa
Star diameter from 90 Antiope • Dia from 61 light curves : 2.14 0.03 mas • For ‘complex’ occultations, correct interpretation of a light curve may depend on results from adjacent chord => need to ensure data is available for re-analysis.