John:
(I don't know if each paragraph will be enclosed in asterisks. That
happened in one of my posts, but not in the other. I use an asterisk for
multiplaction and any spurious asterisk at the beginning and end of a
paragraph shouldn't be confuse with that multiplying asterisk.)
Here is the
Sorry, I accidentally wrote h = , when I meant sin h = , at the
beginning of the formula for h, given Az, Lat, and dec.
Michael Ossipoff
---
https://lists.uni-koeln.de/mailman/listinfo/sundial
I'm sorry--another typo:
I meant to say:
If your input azimuth is west of south, then h and its sine must be
positive.
If your input azimuth is east of south, then h and its sine must be negative
I really didn't mean to post so much, but I wanted to correct those typos.
Michael Ossipoff
Another omission:
By Az, I ;mean your desired azimuth, expressed in angular
distance-in-azimuth from north or south, whichever of those distances is
less (depends on whether your intended azimuth is closer to north or to
south)..
The appeal of the briefer solution that someone else posted is
From: Roger Bailey
Sent: Wednesday, March 04, 2015 5:28 PM
To: Michael Ossipoff
Subject: Re: Jack: Duration of sunlight on a particular day
Hello Michael,
I responded to Jack and provided a spreadsheet that calculated sunrise and
sunset times that included the option for refraction. This
I used your splendid and accurate BSS Horizontal Sundial design pdf but with a
couple of variations. I used a 6 square ceramic tile as the
dial plate, rather than 6mm MDF board, but the making of the gnomon may you
find more interesting. I drew the gnomon by using the
free Sketchup Make
Jack:
You wrote:
*I have been trying to figure out how to plot the duration of daylight over
** the course of the year as a function of latitude. (I would generate a **
curve for each latitude I am interested in.)*
*[endquote]*
*You said to disregard physical effects such as atmospheric
Richard:
You wrote:
If you know the zenith distance, z, of the sun (90° - elevation angle) as
well as the azimuth (A) then you could use:
sin(h) = -sin(z)*sin(A)/cos(delta)
where delta is the sun's declination. The latitude of the site, phi, is not
needed.
Computing the hour angle when the
