27 May 2016

Mars at Opposition

Mars at Opposition
Mars just reached opposition, a time when it is in a straight line with the Earth and Sun. Mars therefore rises at sunset and is visible all night. It is also at its brightest, because usually opposition is also when the planet is at its closest approach to Earth and is fully illuminated, like a Full Moon.

Mars is presently located in Scorpius and as viewed from Earth is going through 'retrograde motion' in which the steady westward movement of the planet is temporarily interrupted by a reversal in motion back toward the east, as the Earth speeds past Mars in its orbit. The path of Mars in the background stars is nicely captured in this image from Naked Eye Planets and shows the retrograde path of Mars quite clearly.

Mars is easy to spot, a bright orange dot in the south that is grouped near another bright orange-red dot (in this case, Antares, the brightest star in Scorpius), and contrasting with a yellow-white dot that is Saturn.

Image courtesy Sky & Telescope