The cast of Heliacal - 2012 includes: Ryan Sirois

Venus rises heliacaly when reaching arcus visionis between 5.3 and 6.0 degrees.

(Arcus visionis is the altitude of the Sun below horizon when Venus is exactly on the horizon).

Because Venus is bright and its brightness is stable, the heliacal rise of Venus can be computed easily. Something that cannot be said for the other planets and stars. The last systematic (and published) observations of heliacal risings were made 2000 years ago in Mesopotamia!

There are several theoretical algorithms for computing the heliacal phenomena, but none of them is reliable because of the lack of observations.

This is soon to be changed.

More on the heliacal phenomena, their computation and real first-hand observations can be found by clicking the 'Related link' below.

Heliacal

heliacal

Light, solar.