Tomorrow, May 22nd, Mars will be at opposition, the point in any planet’s orbit where it is opposite the sun relative to the observer. Well placed high in the southeast at around 9:00 PM, EDT, and located in Scorpius, Mars, being relatively close to us at opposition, rivals giant Jupiter in brightness, further to the west along the ecliptic. Just 2.5 degrees SE of Mars, is its mythological rival (in lore and color), the red supergiant star, Antares. Accompanying Mars and Antares will be the full moon to the NW of Mars, the third and end-point of a line that begins with Antares. Completing the neat quadrangle in the southeastern sky will be majestic Saturn, 2.5 deg. NE of Antares. Tonight’s full moon is this year’s “Flower Moon” and next month’s, the “Strawberry Moon”. Each month, the full moon is associated with an prominent aspect of the current month and season. This month, May, flowers are in full bloom; next month, June, is the Strawberry harvest. A calendar of full moon dates, their names, significance and meaning can be found in the “Old Farmers Almanac”, in Fred Espenak’s Ephemeris and in the Farmer’s Almanac.
During opposition, the distance between two planets, in this case Mars and the Earth, will be at a minimum and if both planets are at perihelion, the distance will be at its absolute minimum or,in other words, they will be as close to each other as possible. With Mars at perihelion in October of this year and Earth at perihelion in January, the two planets are close to this point. Even though they are in opposition tomorrow, the closest approach will be on 30 May. To better understand this we must realize that the two planets’ orbits are unique with the Earth at aphelion (the furthest point from the sun) in July (during the Northern Hemisphere summer, ironically the warmest time of year for that hemisphere). Opposition doesn’t necessarily mean closest approach; that would only occur during the confluence of a shared perihelion.
There was much hype and misinformation circulating during the previous three Martian oppositions, with ominous predictions that Mars would rival the full moon in size, that there was a threat to the Earth or that Mars was going to crash into the Earth. Even at its closest possible approach during opposition, Mars appears only 26 arc-seconds in diameter or the size of a tennis ball at 800 meters (0.5 mile). With its characteristic red-orange color, the only noticeable difference to the casual observer will be a increase in brightness, attributed to its proximity. In order to properly observe Mars, a 15 – 20 cm (6 – 8″) aperture telescope should be used. If you miss this one, the next Opposition of Mars is 27 July, 2018.
Imagination is more important than knowledge
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