Lunar Occultations of Close Double Stars Occultation of

Lunar Occultations of Close Double Stars Occultation of R 946, 2011 November 14 The why and wherefore of observing these events NACAA 2014 April 20 Occultations Session Brian Loader RASNZ Occultation Section SAO 160149 2013 September 12 1

SAO 160149 Occultation Video Frame 2

Occultation Light Curve, Single Star 3

Occultation Light Curve for SAO 160149 4

Double Star Occultation, Light Curve Secondary Intensity Step Length (seconds) Primary Intensity 5

Double Star Occultation, Light Curve 176 ± 78 Step Length (seconds) 1. 16 s 367 ± 42 6

Double – Fainter Star second 7

Double Reappearance 8

Double Star Programme Aims Accurate times of both events Position Angle and Separation and Magnitudes md Discovery of new doubles Confirmation / Rejection Publication of results 9

Solution for R 68 using OCCULT N EE Prediction: 0. 092” 258. 37° 10

Possible Resolution 2 or 3 video frames, ca 0. 1 second … … ca 30 to 35 milli arc-second. . . 60 m on the moon, 1 AU at 100 light years. 11

Total Number of Observations Archived as at 2014 April 6 Year of Obsn. No of Obsn Cumulative up to end 2007 147 2008 75 222 2009 223 445 2010 249 694 2011 196 890 2012 222 1112 2013 184 1296 2014 65 1361 12

Numbers of Observations Received as at 2014 April 6 WDS ‘double’ WDS ‘single’ No. of Obsn. 393 148 No. of stars 209 96 No. > 1 Obsn. 87 34 Max obsns. per star 7(+2 nil) 4 OCc ‘double’ OCc ‘single’ Discoveries Doubtful Dbl Wide Dbl >3” TOTALS 35 498 109 98 80 1331 19 310 82 75 64 855 8 125 14 15 11 294 3 6 6(+2 nil) 4 5 Group 13

Numbers of Observers by Country Australia New Zealand 11 4 Japan 17 USA 9 Europe 7 14

Publication Suitable observations are published in the on-line Journal of Double Stars Observations. http: //www. jdso. org 15

Discovery Papers 16

JDSO July 2010 17

JDSO July 2011 18

JDSO October 2012 19

JDSO April 2014 20

Known doubles, PA and Separation Measured 21

Occultation Discoveries 22

Possible Double Stars shown to be single 23

Observer Separation 10° round the Moon’s limb projected on the Earth’s surface is ca 3° latitude Hobart – Melbourne ca 5° Melbourne – Sydney ca 4. 5° Sydney – Brisbane ca 6° Brisbane – Rockhampton ca 4. 2° Perth Adelaide Murrumbateman 24

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