The Red planet reached opposition Tuesday, April 8 at 21 UT. A planet is at opposition when it is in the opposite direction from the Sun. Earth overtakes it on it’s inside orbit and crosses the line between the planet and Sun. Mars is now rising in the southeast at sunset, is on the meridian at midnight and sets at dawn.
This is the middle of the best time to observe Mars glowing like the ember of a prehistoric campfire, but don’t dawdle. Because Mars’ orbit is slightly elliptical we’ll be closest April 14 at about 0.62 AU (Astronomical Unit) or 58 million miles. The tiny Red planet’s angular size will max out at only 15″ (arc seconds) until about April 21. By comparison Saturn will appear 19″ wide at opposition in May from a distance of nearly 900 million miles!
This will be the best Mars opposition since 2007 but not as near or bright as the opposition of May, 2016 or the brighter yet apparition of July, 2018 which will be more then 3 times brighter than this year.
My friend Don Spain of the Little Bear Observatory in Louisville has devised an interesting observing project for this apparition of the Red Planet. This obeserving project will require a refractor telescope of at least 3 inch aperature or a reflector of 6 inches or more. Download Don’s PDF observing activity sheet, make four or more observations of the Martian surface features, sketch what you see, send him your sketches and he will prepare a map of the Red Planet based on your sketches. Email Don using the above link to request his observing tips, sketch sheets, etc.
Since Mars is just past opposition it is rising in the southeast at dusk. It is best to allow the planet to rise out of the atmospheric muck, so plan to make your observations at around midnight local time when the planet is highest in the south. Mars is presently in constellation Virgo a few degrees west of 0.98 magnitude Spica. Use the chart above, which shows the view to the southeast at midnight local time April 15.