Art & All,

The matter of the international date line has been settled by now. 
Confusion remains about the cave-dwelling lover.

> SÈrgio Garcia Doret <[EMAIL PROTECTED]> writes:
> 
> > 1 - Assume the hours equals exactly 1/24th of the earth revolution time
> > and suppose a disguster lover choose to retire into a cave, where
> > daylight is entirelly shut off for a period of six months to the minute.
> > ... What adjustment does his watch need?
> 
> As pointed out by others, the assumption does not even come close to
> the actual definition of an hour, but what the heck.  The watch owner has
> more important things on his mind.  I see two answers, depending on the
> type of watch:
> 
> 1) If it the usual "stupid" kind, no adjustment will be necessary.  12
>    o'clock is 12 o'clock, and the watch can't distinguish 12 noon from 12
>    midnight.

The guy obviously is an astronomer; why else would he have a 
watch reading siderial time? 
A 'neat' siderial watch should have a 24 siderial-hour face, as it is 
not easy to know in which half of the siderial day one lives at a 
given civil date and time. 

> 
> 2) If the watch has a date display, then it must be adjusted by 12
>    hours, and it makes a difference whether you set it forward or set it
>    back because you wind up on a different day.  The correct procedure is
>    to set it back to give the rotation about the axis time to make up for
>    the revolution about the sun.

As the lover's watch still reads the correct siderial time after leaving 
the cage after 6 months, no adjustment at all is needed, I would 
say.

> 
> --Art Carlson

Kind regards,

Frans Maes
Peize, The Netherlands
www.biol.rug.nl/maes/

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