Sunset angle at soltice

Hi,

At the day of soltice, at a certain latitude, what is the equation that
determines the angulat position of the setting sun. It is most north, but
by how much?

Thanks.

Cheers,
Don W

Donald Wilgus wrote:

At the day of soltice, at a certain latitude, what is the equation that
determines the angulat position of the setting sun. It is most north, but
by how much?

An object's azimuth at setting is to a first approximation

A_s = 360° - acs(sinD*secL),

where D is its declination and L the observer's latitude, ignoring
such effects as atmospheric refraction. Assuming from "most north"
that you're talking about the (northern) summer solstice the sun is
at its maximum declination of about +23°5, so the constant 0.398 can
be substituted for sinD. A few sample values:

Lat. A_s
60° 323°
45° 304°
30° 297°
0° 293°

Due to the symmetry of the secant function WRT sign the azimuths are
the same whether the latitude is north or south.

--Odysseus

Thanks, I'll check it out.
Don W.



"Odysseus" wrote in message
...
Donald Wilgus wrote:

At the day of soltice, at a certain latitude, what is the equation
that
determines the angulat position of the setting sun. It is most north,
but
by how much?

An object's azimuth at setting is to a first approximation

A_s = 360° - acs(sinD*secL),

where D is its declination and L the observer's latitude, ignoring
such effects as atmospheric refraction. Assuming from "most north"
that you're talking about the (northern) summer solstice the sun is
at its maximum declination of about +23°5, so the constant 0.398 can
be substituted for sinD. A few sample values:

Lat. A_s
60° 323°
45° 304°
30° 297°
0° 293°

Due to the symmetry of the secant function WRT sign the azimuths are
the same whether the latitude is north or south.

--Odysseus