Home > Hammer Projection

Formulae

Equatorial coordinate

X = ( 2 √2 cos(δ) sin(α/2) )  ⁄  √( 1 + cos(δ) cos(α/2) )

Y = ( √2 sin(δ) )  ⁄  √( 1 + cos(δ) cos(α/2) )

where (α, δ) = (Right Ascension, Declination)

Horizontal coordinate

X = ( 2 √2 cos(alt) sin(az/2) )  ⁄  √( 1 + cos(alt) cos(az/2) )

Y = ( √2 sin(alt) )  ⁄  √( 1 + cos(alt) cos(az/2) )

where (az, alt) = (Azimuth, Altitude)

Wikipedia

Hammer Projection

Planetarium - Version 1.3.1