Transcript Conjunctions an Oppositions

Planets
Conjunctions, Oppositions and Elongation
Planets without a telescope look just like stars
Except, they move relative to the stars
Conjunctions and Oppositions
In a Conjunction the celestial objects appear
near each other in the sky
In an Opposition the objects appear in opposite
directions,
(If only one object is mentioned the other is
assumed to be the Sun!)
These occur because the earth and the celestial
objects line up
(Please copy all diagrams)
Superior Planets
Superior Planets orbit farther from the Sun
than Earth.
They can be in conjunction or opposition.
They are in Conjunction when they are on the
other side of the Sun.
As far away as they can be from Earth.
They are in Opposition when the Earth is
between the Superior Planet and the Sun.
It is then that they are nearest to the Earth, and
thus are the brightest.
Inferior Planets
Mercury and Venus are inferior planets,
they orbit closer to the Sun than Earth
Inferior Planets can have 2 kinds of
Conjunctions with the Sun
An Inferior Conjunction is when it is between
the Earth and the Sun.
This is when the planet is closest to the Earth,
and thus is brightest
A Superior Conjunction is when it is directly on
the other side of the Sun
Elongation
The elongation of a planet is its distance from the sun in
degrees
Superior planets can have any elongation from 0 to 180°
Inferior planets cannot.
The maximum elongation of Venus is 46°
The maximum elongation of Mercury is 28°
Morning and Evening Stars
Sometimes an inferior planet will rise and set
before the Sun.
You can only see it in the morning before
Sunrise …A “morning star”
At other times it will rise and set later than the
Sun.
It can then be seen only in the evening for a
short time after sunset … an “evening star”
Synodic Period
The Synodic Period of a planet is the time
between two oppositions or conjunctions
of the same type.
This is not the same as the planet’s year…
Because the Earth is moving too!