1. Lunar Occultations of Close Double Stars
Occultation of R946, November 14
Lunar Occultations of Close Double Stars
The why and wherefore of
observing these events
NACAA April 20
Occultations Session
Brian Loader RASNZ Occultation Section
SAO
2013 September 12

2. SAO 160149 Occultation Video Frame

3. Occultation Light Curve, Single Star

4. Occultation Light Curve for SAO 160149

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

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

7. Double – Fainter Star second

8. Double Reappearance

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

10. Solution for R68 using OCCULTE E
Prediction: ” °

11. 2 or 3 video frames, ca 0.1 second …
Possible Resolution
2 or 3 video frames, ca 0.1 second …
… ca 30 to 35 milli arc-second...
60 m on the moon,
1AU at 100 light years.

12. 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
1112
2013
184
1296
2014 65
1361

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

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

15. Publication Suitable observations are published in the on-line
Journal of Double Stars Observations.

16. Discovery Papers

17. JDSO July 2010

18. JDSO July 2011

19. JDSO October 2012

20. JDSO April 2014

21. Known doubles, PA and Separation Measured

22. Occultation Discoveries

23. Possible Double Stars shown to be single

24. 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