A Half-Year Downunder

1. A Half-Year Downunder 2016 July 30 IOTA Meeting OSU, Stillwater, Oklahoma David W. & Joan B. Dunham This is a continuation of our talk on “a year downunder” at the IOTA meeting in mid-October 2015. At that time, we had interrupted our 11-month stay in Australia to come home to visit my dying close colleague of many years, Robert Farquhar (he passed away on October 18, during the last sessions of the IOTA meeting). This describes our experiences in Australia after we resumed our stay there on 2015 October 29.

2. The RASNZ Annual Meeting and the 9th Trans-Tasman Symposium on Occultations drew us to New Zealand for 11 days before our long stay in Australia, in mid May 2015. Our stay in Australia ended with the National Australian Convention of Amateur Astronomers in Sydney on Easter weekend, late March 2016. The 10th Trans-Tasman Symposium on Occultations was also held there, starting on the last day of NACAA.

3. Sept. 11, 19:59 UT, occultation of 9.2-mag. star by Asterope Joan and I ran 11 stations along the Stuart Hwy from Wycliffe Well to Churchills Head (northern attended station), 3 120mm maxi’s, 6 80mm midi’s, a mini with an integrating camera, & the 10in. scope. The 3 southern stations had no occultation, station 4 camera battery was too low, and the 7 others were all positive, a record for us. The PPMX catalog showed a large north shift (see below) which is why we set up as far north as Churchills Head (good thing we did) & later work by S. Preson confirmed a north shift likely. failed Generated and posted by Brad Timerson Most stations didn’t have VTI’s so in 2016 Feb. we tested ZR’s

4. Sept. 11, 19:59 UT, occultation of 9.2-mag. star by Asterope The northernmost & southermost chords 1 & 8 were VTI time-inserted. This shows non-linear drift may be a problem with some of the Canon ZR camcorder clocks; 3 test runs have quantified those drifts. 30th anniversary of ICE at GZ!

5. October 8, central Australia, the 15% sunlit waning cresent Moon occulted Venus, providing an opportunity to try to record Ashen light on dark side of Venus for about 30s before the sunlit part reappeared. This was our last observation before returning to the US around the time of the IOTA meeting; much more about it is in a separate presentation. The video can be seen at https://www.youtube.com/watch?v=r6TsRBQaMzI&feature=youtu.be X15189 Venus

6. Gosses Bluff (impact structure) Inside Gosses Bluff We returned to Alice Springs for a week around the start of Nov., to better explore the MacDonald Ranges and Gosses Bluff, that we hadn’t seen earlier during our stay in Alice Springs.

7. Move to Canberra & NSW trips, late 2015 – early 2016 “Pitch Black” Spaceship Sundial, D. Herald & M. Streamer Coober Pedy, SA Murrumbateman, NSW One Tree Hill, north ACT On Mount Kosciusko, NSW

8. nw of Dubbo, NSW for Lampetia occ’n, mid November 2015 As usual, Joan helped a lot with this deployment; about 400 km n. of our home in ACT On 2014 Aug. 24, I had 5 +’s and 1 – for this asteroid in cen. Missouri

9. Moree, NSW for Sidonia occ’n, mid December 2015 AU Telescope Compact Array, Narrabri Warrambungle National Park Solar System Model from AAO (579) Sidonia profile, 2015 Dec. 17 A collaboration with John Broughton

10. Tasmania, 2016 January, with brother Douglas & wife Cape Pillar Mount Cradle At a Café Tasmanian Devil

11. 2016 Feb. 4, Graze of SAO 106879 n.e. of Bridgeton, WA Star mag. 7.6, Moon 16%-, CA 3S, alt. 28 deg.

12. 2016 Feb. 4, Graze of SAO 106879 n.e. of Bridgeton, WA Star mag. 7.6, Moon 16%-, CA 3S, alt. 28 deg. Above left: Path across W. Aus. Above: Whole path over region northeast of Bridgeton Left: Detail of the “best” zone for the attended stations

13. 2016 Feb. 4, Graze of SAO 106879 n.e. of Bridgeton, WA Star mag. 7.6, Moon 16%-, CA 3S, alt. 28 deg. We ran 2 remote and 2 attended stations with 3 midi’s and 1 maxi. The maxi successfully recorded a few occultations of the star, but the star was too faint for useful data from the midi’s

14. e. of Northam, WA for Desiderata occ’n, early Feb. 2016 Lake at Northam Wave Rock, Hyden Pinnacles Nat’l Park, Cervantes (344) Desiderata profile, 2016 Feb. 8

15. The ZR camcorders and MiniDVR’s that didn’t have real-time IOTA-VTI time insertion were tested on 3 nights, with similar times (relative to sunrise) & temperatures that occurred for the 2015 Sept. 11 Asterope & 2016 Feb. 8 Desiderata occ’ns The deviations from a constant rate were similar for the 3 tests, so the times were improved by applying an average of the test corrections, resulting in smaller residuals for the fits, shown in the next slide. Without tests like these, the results show that errors of a few tenths of a second are likely for past occultations where the recorder clock was used for timing, and errors >1s can occur if the IOTA-VTI calibrations are half a day or more from the event.

16. Sept. 11, 19:59 UT, occultation of 9.2-mag. star by Asterope With 7 chords recorded across the length of the asteroid, this was our most successful effort ever to observe an asteroidal occultation.

17. 2016 March 25-28, Sutherland, we attended 50th NACAA, and TTSO10 after it, while staying in the Sydney area during the last part of March (we explored the Blue Mountains and Sydney). We returned to the US in time for the April 5th occultation by (216) Kleopatra (separate presentation), and the North East Astronomy Forum 5 days later.

18. Torres Strait Laura Red – previous, D,J,&W Blue – previous, D only Green – 2015-6, D & J Orange – 2015-6 & previous