1. Universal Time by IOTA-VTI GPS-ABC ADVS Dave Gault on behalf of T.A.C.O.S Presented to Trans-Tasman Symposium on Occultations No.8 2014 Friday, 18 th April 2014 Melbourne, Australia

2. The Australian Contributors for Occultation Science T.A.C.O.S. currently Tony Barry, Dave Gault, Dave Herald and Hristo Pavlov

3. Universal Time from GPS + = Universal Time +/- 0.000001 sec (GPS manufacturer’s specification) {} Device accuracy = +/- 0.0001 sec Note to self… 1pps LED lit on all devices Note display delay

4. IOTA-VTI International Occultation Timing Association – Video Time Inserter

5. IOTA-VTI Screens Position Screen Time Screen

6. IOTA-VTI GPS Almanac Management System (GPS-AMS) A C B A = alert if IOTA-VTI house keeping is incomplete and is unsure of the quality the current almanac. B = time of the last Almanac Update C = Correction to apply to previous timings if an Almanac update occurred

7. IOTA-VTI Data Quality Assurance (DQA) “ Live ” On Timer Screen IOTA-VTI samples the serial data and the 1pps from the GPS every second 5 tests every second + 1 test sequentially over an hour Overall policy is to ‘squawk’ loudly on error Reports on status of satellite fix

8. GPS-ABC Global Positioning System – Atomic Bomb Clock for visual occultation observations

9. The coded beep of GPS-ABC every second= normal beep beginning of the minute = long beep 10th, 20th, 30th, 40th and 50th seconds= short beep 55th, 56th. 57th and 58th second= brief beep 59th second = silent (no beep) GPS-ABC has a clear and static free coded time-beep Click to hear GPS-ABC and John Vetter in action Or goto YouTube - http://www.youtube.com/watch?v=32NYYs_9AS8http://www.youtube.com/watch?v=32NYYs_9AS8

10. GPS-ABC Almanac Management and Position Sentence

11. Hand Wired GPS-ABC #8 by Chris Chad Cost ~ $115 in parts

12. Printed Circuit Board GPS-ABC Home Assembly or Ready-to-Go Option a; Home Assembly - owner purchases the three major components and a KIT-of-Parts - about an afternoon of work with basic tools and a soldering iron… ……… Cost about $199 Option b; Purchased Fully Assembled, Tested, and Ready-to-Go …………….. Price $249 the catch, I need orders for 10 to purchase the PCB – currently @ 2 contact Dave for more info.

13. ADVS Astronomical Digital Video System

14. ADVS features at a glance Astronomical Digital Video System; is progressive scan video is all digital is 12bit data (Flea3) and 14bit data (GrasshopperEx) exposure range 30 frames per second to 8 seconds per frame has one CCD read noise per frame frame Central Exposure Time accuracy +/-0.001 seconds UT no Instrument Delay compensation required OSD not overlayed on the image data, does not block FOV has control of camera gain, gamma and offset has three modes of screen gamma (linear, lo-gamma & hi-gamma) uses.adv file format.adv file can be repaired if not closed properly (i.e. power outage) video analysed using Tangra3 video easily converted to FITS, complete with metadata supports 3 models of cameras

15. ADVR screens Key =r to record s to stop Keystroke Menu

16. ADVR screens Almanac ready or not GPS Almanac Uncertain -Red question mark -Yellow time display means time is uncertain GPS Almanac now current -No red question mark -Green time display means:- time is now certain --1 means yellow times were incorrect:- subtract 1 second

17. Tangra 3 by Hristo Pavlov

18. Questions?