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Old 01-04-2009, 10:17 AM
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gary is online now
Join Date: Apr 2005
Location: Mt. Kuring-Gai
Posts: 5,299
Arrow Argo Navis and Daylight Saving

Originally Posted by erick View Post
By the way, I'm fairly sure my Argo went off daylight saving last weekend, not that it matters in its operation. Did I spot it correctly? Haven't had time to check since.
Hi Eric,

Your Argo Navis would not have changed its timezone off daylight saving
last weekend. That requires intervention on part of the user, specifically
you would need to enter MODE SETUP, SETUP DATE/TIME and change
the TIMEZONE setting.

Internally Argo Navis maintains the date and time in terms of UTC time,
which is similar to GMT. The TIMEZONE setting in SETUP DATE/TIME
is simply a convenience feature that allows you to enter your offset from
UTC and then your own local date and time. Argo Navis will then do
the arithmetic for you and convert that entry to UTC date/time.

The TIMEZONE setting also is used should you want to view the LOCAL
time in MODE TIME.

Since Argo Navis internally uses UTC and since there is no concept of Daylight
Saving for UTC, if your own part of the world observes Daylight Saving and
goes onto it or comes off it, as far as operation of your Argo Navis is
concerned, it matters not. So, for example, if you forget to change the
TIEMZONE for Victoria next weekend from +11:00 back to +10:00, then
internally the Argo Navis UTC time remains exactly the same and calculation
of positions of planets and any time dependent functions remain correct.
At your leisure, you might then go into SETUP DATE/TIME and change the
TIMEZONE and then press EXIT and Argo Navis will then also show the
correct local time in MODE TIME.

So in a nutshell, Argo Navis does not automatically change the time with
Daylight Saving and since it stores internal time in terms of UTC, it has
no need to. Changing the TIMEZONE setting requires user intervention
and is a non-critical operation as far as the computations the unit performs.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
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