Celestial Bodies - rhannequin/astronoby GitHub Wiki

Currently, Astronoby only supports the following major bodies of the Solar System:

• the Sun (Astronoby::Sun)
• planets from Mercury to Neptune, including the Earth (Astronoby::Earth, ...)
• the Moon (Astronoby::Moon)

Given an ephemeris (Astronoby::Ephem) and an instant object (Astronoby::Instant), these classes enable to get instances which provides positions in different reference frames.

You can learn more about ephemerides and reference frames.

ephem = Astronoby::Ephem.load("inpop19a.bsp")
time = Time.utc(2021, 7, 8)
instant = Astronoby::Instant.from_time(time)

venus = Astronoby::Venus.new(ephem: ephem, instant: instant)
apparent_position = venus.apparent.position

apparent_position.x.km.round
# => -148794622

Each of these bodies also provide their own equatorial radius (Astronoby::Distance).

Astronoby::Venus::EQUATORIAL_RADIUS.meters
# => 6051800

Attributes of planets

For all Solar System bodies, except the Sun and the Earth, the following attributes are available. Note that dynamic values accessible through instance methods, while absolute values are accessible through class methods.

#constellation

Constallation where the body appears in the sky as seen from Earth. Returns a Astronoby::Constellation object.

venus.constellation.name
# => "Cancer"

venus.constellation.abbreviation
# => "Cnc"

#phase_angle

"Sun-object-Earth" angle. Returns a Astronoby::Angle object.

venus.phase_angle.degrees.round
# => 40

#illuminated_fraction

Fraction of the object's disk illuminated as seen from Earth. Returns a Float between 0 and 1.

venus.illuminated_fraction.round(2)
# => 0.88

#apparent_magnitude

Apparent brightness of the body. Returns a Float.

venus.apparent_magnitude.round(2)
# => -3.89

::absolute_magnitude

Absolute brightness of the body. Returns a Float.

Astronoby::Venus.absolute_magnitude
# => -4.384