Re: They call it 'Earth hour'
- From: Dr J R Stockton <reply0913@xxxxxxxxxxxxxxxxxx>
- Date: Sat, 28 Mar 2009 14:18:13 +0000
In sci.astro.amateur message <270320091744199226%star@xxxxxxx>, Fri, 27
Mar 2009 21:44:21, Davoud <star@xxxxxxx> posted:
Dr J R Stockton wrote:
Can some manufacturer of 32768 Hz watch/clock crystals be persuaded to
offer in addition similar 32857.7 Hz crystals (check figure first)?
Then a little deft work with a soldering iron should make your chosen
clock sidereal.
A soldering iron in a wristwatch? One who succeeded at that would
probably get the Nobel for deftness. If you aren't familiar with that
particular prize it's because they don't often award it.
In sci.astro.amateur message <260320091422230893%star@xxxxxxx>, Thu, 26
Mar 2009 18:22:22, Davoud <star@xxxxxxx> posted:
I've been looking for an inexpensive, analogue, sidereal wall clock
_and_ for a sidereal wrist watch in the under $1k range for the longest
time. Any hints?
You were also looking for a wall clock; others were looking for a wall
clock too. And I wrote "clock".
Nevertheless : you may not have them in your unspecified country - but
for years I used Weller thermostatically-controlled soldering irons with
interchangeable substantially pointed bits. A little work with a needle
file, or long use, could produce a point as sharp as might be needed. I
also used, occasionally, a much smaller iron, for which a new bit had a
small sharp edge that could be easily filed to a point. Granted, it
requires a suitable iron; I also had one the size and shape of a young
cricket bat - but perhaps you so not have those where you live.
I have experience of soldering wire in the upper forties SWG; even 50
SWG, I think.
Alternatively, one of the pins of a standard crystal circuit is driven
from the chip and the other goes to a chip input. With the aid of a
phase-locked loop and another frequency source, such as an adjacent
mean-solar clock, and having removed the crystal from the would-be
sidereal clock, drive that input with a waveform at the above frequency
and sufficiently[*] similar in shape to what it usually sees.
A wristwatch that also requires a backpack is not exactly what I was
looking for :<)
AISB, you also wanted a wall clock, as did others. But one who *really*
wants a wrist display should be able to accept a thin wire pair running
up inside the sleeve and down into a pocket.
The clockwork watch I am wearing today has a 3 cm dial; perhaps some
enterprising manufacturer supplies 3 cm wearably-mounted LCD (or better)
displays driven through a nice thin lead ...
--
(c) John Stockton, near London. *@merlyn.demon.co.uk/?.?.Stockton@xxxxxxxxxxx
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