Latitude from zenith angle and declination

Knowing the zenith angles and declinations of the northern and southern stars, it is possible to determine the latitude of the observation site.

Notes:

  1. Northern star is any star north of the zenith with known declination.

  2. Southern star is any star south of the zenith with known declination.

Conditions:

  1. Both stars are at upper transit (culmination).

latitude

latitude of the observation site.

Symbol:

phi

Latex:

\(\phi\)

Dimension:

angle

north_zenith_angle

zenith_angle of the northern star.

Symbol:

theta_N

Latex:

\(\theta_\text{N}\)

Dimension:

angle

south_zenith_angle

zenith_angle of the southern star.

Symbol:

theta_S

Latex:

\(\theta_\text{S}\)

Dimension:

angle

north_declination

declination of the northern star.

Symbol:

delta_N

Latex:

\(\delta_\text{N}\)

Dimension:

angle

south_declination

declination of the southern star.

Symbol:

delta_S

Latex:

\(\delta_\text{S}\)

Dimension:

angle

law

phi = (theta_S - theta_N + delta_S + delta_N) / 2

Latex:
\[\phi = \frac{\theta_\text{S} - \theta_\text{N} + \delta_\text{S} + \delta_\text{N}}{2}\]