Universal TimeUniversal Timebyby

IOTA-VTIIOTA-VTIGPS-ABCGPS-ABC

ADVSADVS

Dave Gault on behalf of T.A.C.O.SDave Gault on behalf of T.A.C.O.S

Presented toPresented toTrans-Tasman Symposium on Occultations No.8 2014Trans-Tasman Symposium on Occultations No.8 2014

Friday, 18Friday, 18thth April 2014 April 2014Melbourne, AustraliaMelbourne, Australia

The Australian Contributors for Occultation ScienceT.A.C.O.S.

currentlyTony Barry, Dave Gault, Dave Herald and Hristo Pavlov

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 devicesNote display delay

IOTA-VTIInternational Occultation Timing Association – Video Time Inserter

IOTA-VTI Screens

Position Screen Time Screen

IOTA-VTIGPS 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 UpdateC = Correction to apply to previous timings if an Almanac update occurred

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

GPS-ABCGlobal Positioning System – Atomic Bomb Clock

for visual occultation observations

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 actionOr goto YouTube - http://www.youtube.com/watch?v=32NYYs_9AS8

GPS-ABCAlmanac Management and Position Sentence

Hand Wired GPS-ABC #8by Chris Chad

Cost ~ $115 in parts

Printed Circuit Board GPS-ABCHome 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.

ADVSAstronomical Digital Video System

ADVS features at a glanceADVS 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

ADVR screensADVR screens

Key = r to records to stop

Keystroke Menu

ADVR screensADVR screensAlmanac ready or notAlmanac ready or not

GPS Almanac UncertainGPS Almanac Uncertain- Red question markRed question mark- Yellow time display means Yellow time display means

time is uncertaintime is uncertain

GPS Almanac now currentGPS Almanac now current- No red question markNo red question mark- Green time display means:- Green time display means:-

time is now certaintime is now certain- -1 means yellow times were -1 means yellow times were

incorrect:- subtract 1 secondincorrect:- subtract 1 second

Tangra 3Tangra 3by Hristo Pavlovby Hristo Pavlov

Questions?