[LEAPSECS] operational time -- What's in a name?

Rob Seaman seaman at noao.edu
Mon Mar 31 19:29:07 EDT 2008


Clive D.W. Feather wrote:


> Um, what buttons on the back? My kitchen RC clock has none such

> (probably because just about all of the UK is in the same time zone).


Right. A typical such clock in the U.S. will have one set of radio
buttons for Eastern/Central/Mountain/Pacific timezones and a second
button labeled "DST" whose precise purpose is unclear without reading
the manual. There may also be other button(s) for manual operation.

I don't know what folks do in Hawaii, Alaska and other outlying
timezones. At the observatory the issue we have seen is that the
various conference rooms will have an array of several clocks, say
Hawaii, Tucson, Washington, DC and La Serena, Chile. Originally
somebody will have bought 4 spiffy "atomic" clocks without
understanding that Chile is not supported.

What then happens is that the clock #4 is gimmicked during northern
summer (southern winter) to be Eastern Daylight Time (= Chile Standard
Time, GMT-4). During the winter months (southern summer) this fails
since DST in Chile is outside the range of the clocks. The model
clock I'm thinking of can't have the RC manually disabled, so for half
the year, the clock is either wrong or taken down from the wall or
replaced with something that no longer matches the other three
clocks. (I suppose someone could open it up and disable the radio.)

Evidently, the requirement was never considered for a clock to be
located in one place (with one radio standard), but to display time
for another place. The market for a general enough clock to be
portable to any timezone must be quite slim.

Rob



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