Michael,
Thanks for your replies.
On 2018-09-27 8:50 PM, Michael Ossipoff wrote:
I'll fill in those topics*, describing the derivation in more detail,
in postings here, if you'd like [ ... snipped ...]
*for the problem of finding how azimuth-misaligned the dial must be,
to have a given wrong time-reading, at a given local true solar time
and solar declination.
I'll take a rain check on that, if I may. I have received explanations
(off list) from Brian Albinson and Hank De Wit which I want to finish
studying before asking for more help.
By the way, I should add that of course all that's necessary is that
the dial be azimuth-rotated so that it tells the time that it should
tell, and so it isn't necessary to solve the problem that we're
talking about in order to azimuth-align the dial.
Yes, of course - but I'm not going to be correcting the dial myself. I
will tell the parks department what I think is wrong and I want to
provide nice simple guidance to help them decide if they want to do
anything about it. Saying something like "Twist the dial about the
vertical, so that rod in the middle is on a north-south line with the
upper end pointing towards the north pole. The line has to be true
north-south not magnetic north-south. You'll need to move it by 7.5
degrees" is more likely to get action than a procedure that requires
them to obtain and work with local solar time (extra hard for a dial
that only shows hours and half hours, and for a job that likely wouldn't
be carried out at a specific date and time).
Steve
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