User`s guide

120 Starry Night User’s Guide
Planetary Events: A Solar Transit is the
passage of one planet across the face of the
Sun. These rare events require the use of a
safe solar filter designed specifically for
viewing the Sun.
Greatest Elongation is the greatest angular
distance to the east or west of the Sun
reached by a planet, usually Mercury and
Venus. When a planet is at its eastern
elongation, it sets after the Sun and is at its
best visibility in the evening sky. When a
planet is at its western elongation, it sets
before the Sun and is at its best visibility in
the morning sky.
There are two types of Solar Conjunctions.
An Inferior Conjunction is the passage of
Mercury or Venus between Earth and the
Sun. The outer planets cannot pass
between Earth and the Sun and therefore
cannot come to inferior conjunction. A
Superior Conjunction is the position of a
planet when it is on the far side of the Sun
(and in conjunction with the Sun).
A Quadrature occurs when the angle
between the Sun and a planet is 90 degrees
or a quarter of a circle. Eastern Quadrature
is defined when a the planet is 90 degrees
to the east of the Sun, and Western
Quadrature when a planet is 90 degrees to
the west of the Sun.
Solar Opposition is the position of a planet
when it is opposite the Sun in the sky.
Graph Tool
The Graph offers a way of examining
changes in an object’s qualities over time.
The horizontal axis of the Graph always
plots time, while the vertical axis can plot
one of several different qualities
(magnitude, altitude in sky, distance, etc.).
It is possible to plot more than one object
on the Graph at one time.
Opening the Graph: You open the Graph
by clicking and dragging down the area on
the Starry Night window between the the
toolbar and the sky view. As you drag
down, a graph is revealed. By default, the
Moon and Sun are plotted when you open
the Graph.
Tip: You can also open/close the graph by
pressing Ctrl-G (Windows) or Cmd-G
(Macintosh).