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Gerard,
You could make a sheperd's dial. These are location
specific.
Attached is a picture of the scale for such a dial
with correction for longitude and equation of time.
It would be better if you make two, one for the
morning hours and one for the afternoon hours.
Red cq blue lines in the picture.
Also a Capuchin dial for one latitude can be
corrected for longitude and EoT but also split the pattern in two
parts.
Correction for daylight saving time is no more then
adding new numbers to the dial.
Such altitude dial will not work accurate around
noon but the possibility to make them for clock time is present.
Best wishes, Fer.
Fer J. de Vries
Eindhoven, Netherlands
lat. 51:30 N
long. 5:30 E
----- Original Message -----
Sent: Tuesday, October 17, 2006 8:36
PM
Subject: Heliochronometer card
dials?
Ok, so I do realize
that "heliochronometer" and "card dial" are sort of
mutually exclusive. I’m
looking for a way to make some easy to read card dials that read in standard
mean time.
I work at a number of historical reenactment fairs and I’d
love a quick and portable way to show people how fun sundials can be and that
sundials can be accurate. I have a number of universal ring dials but they
read LAT. I’d like the dial to read in mean time because initially I’d like to
be able to skip the explanation of Local Apparent Time vs. Mean Time and such.
I
realize that altitudinal card dials are not the most accurate, but since there
is no such thing as a pocket Schmoyer dial I’m looking for an alternative that
offers simplicity and a hook to catch people’s interest--and I'll be using
them in the summer so the sun will have some altitude for the dial to discern.
*
I’m
considering drafting latitude, longitude and date specific Capuchin dials
corrected for daylight savings and the equation of time. I realize these dials
would be one offs only of use at one location at one date, but since card
dials can be drafted fairly easily this seems like a reasonable way to go.
Granted, one can make a "universal" Capuchin dial that compensates for
latitude and the time of the year, but such a dial still reads in LAT--Perhaps
I could make two rotating hour wheels that line up with the hour scale to set
for daylight savings, longitude offset from the center of the time zone and
the equation of time (one for am and one for pm--I don't think there is a way
to make a single wheel work)
I’m wondering if people have any alternate
suggestions and ways to make drafting more efficient on my Adobe CS2 equipped
non-Intel Mac? (that is, I don't have Delta CAD at the
moment.)
Thanks,
Gerard
*Others may think that the
path of the sun is fascinating as it is and doesn’t need to be equated with
mean time, but I, personally, didn’t become fascinated by dialing until I
discovered all the reasons why the dials I saw in parks didn’t read clock time
and I assume that others may be dismissive of sundials for similar
reasons.
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