planet watch
above the solar system
Volume 23 -- Issue 4
Above the Solar System -- April 2017

Name April 01 April 11 April 21
Mercury 128o 44' 176o 59' 212o 46'
Venus 195o 34' 211o 40' 227o 42'
Earth 191o 27' 201o 18' 211o 05'
Mars 067o 32' 072o 46' 077o 56'
Ceres 060o 50' 062o 58' 065o 10'
Jupiter 197o 43' 198o 29' 199o 14'
Saturn 262o 13' 262o 32' 262o 50'
Plot planet positions using polar graph paper that you can download from this web site - or at that web site create your own.

This uses a coordinate system called heliocentric longitude where the 0o point is at the April or Vernal Equinox coordinate of 0 hours Right Ascension. From 0o longitude an object's orbit around the Sun and its heliocentric longitude increase at a rate determined by the orbital speed of the particular planet. The planet motion is counterclockwise as the animation below shows. Using the coordinates provided here a planet position may be plotted using degrees ranging from (0o to 360o) of heliocentric longitude. Once plotted the orbital position of one planet could be compared with that of another planet. Or the relative orbital speeds of an inner planet could be compared with that of an outer planet.

Terrestrial Planets and Dwarf Planet Ceres in Motion at 5 day intervals.
Above the Terrestrial Planets - April 2017

Click here to see an animated graphic showing the
Terrestrial Planets orbiting the Sun during 2017.

Explore our Solar System with this really cool tool. Click here to go to the Solar System Scope web site.