Exercise:

From St.Andrews, at 6 pm on 1998 February 2nd,
the Moon appeared at altitude +39°, azimuth 196°,
while Saturn is at altitude +34°, azimuth 210°.

How far apart did the two objects appear?

The difference in azimuth is 14°.

Use the cosine rule:
cos MS = cos MZ cos ZS + sin MZ sin ZS cos Z = 0.98
so MS = 12.3°

Which was further east?

The Moon is further east, and higher up, than Saturn.

Back to "the alt-az system".