[LEAPSECS] Straw men

[Ian Batten]

On 9 Jan 2012, at 16:32, Gerard Ashton wrote:


> On 1/9/2012 10:55 AM, Ian Batten wrote:

>> pace all the bizarre claims about bear hunting

> 

> There are a number of laws and rules related to sunset and sunrise, including hunting, turning headlights on

> in automobiles, and being present in parks. No reliable evidence has been presented as to whether

> authorities try to enforce these close to the cut-off time. The only agencies I have seen that actually

> publish sunset and sunrise times for the public to make it easier for the public to avoid violations

> are agencies that regulate hunting and fishing. These agencies will have to examine their calculation

> method to make sure the change does not affect them.


The only practical source for sunrise and sunset times is published data (it's called "lighting up time" in the UK).  That data will be published in civil time, and you are expected to keep your watch in civil time.  Unless you make a habit of keeping old newspapers so you can reuse the published information on the same date a century later, or you keep old nautical almanacs for the same purpose, it's hard to see how this is affected by making civil time UT1, UTC, TAI or anything else: so long as the events are published in the same scale as people are expected to keep their watches in, it's all good.

In any event, the error associated with unhitching UTC from UT1 will accumulate at around a minute per century.  One minute of time is 1/1440 of a day, which is 17 miles at the equator.  So if you went hunting at the equator with 100 year old data for sunset, unless the sunset is published at 17 miles intervals and you're expected to know the correct value, the slew between UT1 and UTC is a smaller factor in the calculation than is your position.  If anyone seriously believes that legislation about lighting up, hunting hours and so on is enforced to one minute precision, I have a bridge to sell them.  

And if you are worried that in fact it might be enforced by a GPS-toting warden with OCD issues, then all  you have to do to protect yourself against this savage assault is to to turn your lights off and pick up your shotgun a minute later in the morning, and turn your lights on a put your shotgun down a minute earlier, than the published values.  That'll give you  a century's protection from the problem.

ian