Dominic Ford, Editor
From the Outer Planets feed
Unlike most of the planets, which follow almost exactly circular orbits around the Sun which only vary in their distance from the Sun by a few percent, Mars has a significantly elliptical orbit. Its distance from the Sun varies between 1.38 AU and 1.67 AU – a variation of over 20% – meaning that it receives 31% less heat and light from the Sun at aphelion as compared to perihelion.
Mars's distance from the Sun doesn't affect its appearance. From Ashburn, at the moment of aphelion it will be difficult to observe as it will appear no higher than 13° above the horizon. It will be visible in the dawn sky, rising at 05:12 (EST) – 2 hours and 2 minutes before the Sun – and reaching an altitude of 13° above the eastern horizon before fading from view as dawn breaks around 06:27.
The position of Mars at the moment it passes aphelion will be:
|Object||Right Ascension||Declination||Constellation||Magnitude||Angular Size|
The coordinates above are given in J2000.0.
|The sky on 07 October 2017|
17 days old
All times shown in EDT.
The circumstances of this event were computed using the DE405 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).
This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.
|07 Oct 2017||– Mars at aphelion|
|27 Jul 2018||– Mars at opposition|
|31 Jul 2018||– Mars at perigee|
|16 Sep 2018||– Mars at perihelion|