AND AUSTRALIA TIME RESOURCES
SINCE 2006, ONLY LIMITED UPDATES HAVE BEEN MADE TO PARTS OF THIS
WEB SITE. WHILE MOST OF THE INFORMATION HERE IS CORRECT AND
RELEVANT, THE SITE IS NOW SLOWLY "SLIDING" INTO BECOMING OUT OF
DATE. FOR NOW, THIS INFORMATION IS LEFT ON THE SERVER
BECAUSE IT INCLUDES SOME GOOD MATERIAL AND HISTORIC REFERENCES.
WE RECOMMEND YOU
ALSO USE OTHER SITES AND CONTACTS TO GET MORE UP TO DATE
INFORMATION. WHAT YOU FIND HERE IS NOT NECESSARILY 'WRONG' BUT
THERE MAY BE OTHER, BETTER WAYS TO ACHIEVE YOUR AIMS. YOU
ARE STILL WELCOME TO CONTACT THE ORIGINATOR OF THIS SITE WITH
CORRECTIONS OF MAJOR ERRORS.
AT SOME POINT IN THE FUTURE THIS SITE WILL BE
DISCONTINUED BECAUSE THE
WEBMASTER HAS A NEW RANGE OF ACTIVITIES AND INTERESTS.
IF ANOTHER PERSON
(INTERESTED IN A FIELD SUCH AS ASTRONOMY, GEOPHYSICS, ETC.) WOULD LIKE
TO TAKE OVER THE MANAGEMENT OF THIS SITE, PLEASE CONTACT THE
timing_nza EMAIL ADDRESS.
Most bold, underlined text contains links to connected or
related web sites.
If you can help with additions, corrections, etc. please
contact us at:
WHAT TIME FORMAT AND
ACCURACY DO YOU NEED ?
CONSIDER YOUR REQUIREMENTS:
- We assume that you have no problem working out the hour and
minute. This web site is concerned with getting the right second
and fraction thereof.
- Many people in homes and offices are quite happy with an accuracy
of "a few seconds" or "about one second". For this you can use
radio time pips on the hour, most handheld navigation type GPS
receivers, some telephone
services, and setting the computer clock from an Internet NTP server.
some other regions of the world, 'radio controlled' (so called
are often used.
- But for visual, manual scientific observations a reliable time
accurate to 0.1 second (100 ms) or better is generally
required. In some
(ref. below), the telephone 'speaking clock' or shortwave radio is a
low cost solution and may just be good enough
the task. However, a dedicated GPS time
(i.e. not a standard navigation GPS) would still be a superior
- For instrumental timing (video or photometer), we really need 10
ms or 1 ms or better. The most practical option here is a GPS
device with a dedicated time function
that uses the 1 PPS time output (i.e. not an average standard
- (** For the connoisseurs amongst our readers we shall not enter
here the discussion over the definitions of, and differences between
'accuracy', 'inaccuracy', 'precision', 'uncertainty'...... that would
be a whole separate book..... Please forgive any errors here.)
- How will an observed "Event"
be related to a "Standard Time" system? Where and
in which directions are known 'delays'.
- Do you need a time reference for a "Single Spot Check"? Such as
'setting' a stopwatch or observing one single well defined event?
At a 'set' time, or at a time of your choosing?
- Or do you need a recordable "Continuous
Time Stream for ~ many minutes or longer?
For example for an asteroidal occultation or a grazing lunar
- For Video recording the best, and now readily available, option
is a GPS based Video Time
FOR SERIOUS WORK:
OF TIME - Direct Links to a Primary Time Standard:
- GPS - using the dedicated 1 PPS
time output - EXCELLENT
- for accuracy and availability, GPS is the superior option,
but Dedicated GPS Time devices are required for
high accuracy. (Caution: NOTE that the time display
on standard handheld 'navigation' GPS units is often a few seconds off).
- Short Wave Radio Standard Time Stations - GOOD - depending on
reception, these stations offer very decent accuracy and good
reliability - WWVH, WWV, CHU, etc. Very good if you
can elect to perform your time check at a time of the day with good SW
- Setting the Computer clock - very convenient, with fair accuracy
depending on the method, hardware and operating system used and the
type of computer link
- Low Frequency self correcting clocks
- generally these are not expected to work reliably in
the New Zealand / Australian region for lack of a local transmitter,
but a few sporadic reports suggest you could be lucky....
- Telephone (fixed line, GSM,
CDMA, UMTS, 3G) - convenient, limited accuracy,
please refer to the
page for specific considerations, depending on the
source of time used for each available number and the transmission mode
(fixed line or mobile / 'cell' ).
- Regular FM / MW Broadcast
Radio - usable in some cases of well specified
time pips on the full hour. Increasing concerns over changes in
time source used, networking arrangements and current and/or future
To carry 'time' between a device linked to the primary source and
e.g. a remote field site, or a group of multiple observing stations, or
to maintain local time when the primary source is inaccessible, we may
also use a (secondary)
Local Clock like a clock,
stopwatch or electronic
bleeper, which is first synchronised with a primary time source and checked again after the observing run.
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