Oh, no! I think I may have my initial term for tan gamma inverted, so my
result would be an angle relative to EW.
I have to go out for the day now, but will check my calculation when I
get home.
Steve
On 2024-07-20 8:50 a.m., Steve Lelievre wrote:
On 2024-07-20 7:01 a.m., John Goodman via sundial wrote:
My ultimate objective is to find the sun's hour angle on a given day, in a
given location, when it reaches a selected azimuth.
John, here's my attempt. I've never used this result so my calculation
needs checking.
Cheers,
Steve
/δ/is solar declination
/φ /is latitude
/ω/is hour angle
/γ/is azimuth
Solar position vector S is
so
Rearrange:
Above equation is of form:
Using trig identities:
where and
in which case
or
or
We have to watch out for quadrant in inverse functions.
--
https://www.gnomoni.ca
https://www.youtube.com/@gnomonica
---------------------------------------------------
https://lists.uni-koeln.de/mailman/listinfo/sundial
