Monday evening September 29th the waxing crescent Moon will be about 6o from the planet Mars. Mars in turn is about 3o away from its nemesis, so to speak, the reddish star Antares in Scorpius the Scorpion. Why the ‘nemesis’? The name Antares translates into rival or anti Ares, the Greek G-d of war. It is thought that the name for the star was given at a time when the two are like they are now – separated by only a few degrees. It may have been an attempt to differentiate between the two at the times when they are close and their respective colors appear similar.
Whatever the reason for the name it is always interesting to compare the two objects, both for color comparison, as well as for comparing the their respective apparent magnitudes. Mars currently shines with an apparent magnitude of 0.80, while Antares has an apparent magnitude of 1.03. There are times when the magnitude comparison is in favor of Mars. This would be when Mars is at or near opposition, and Earth is at or near aphelion. How often this happens is a factor of how many years it takes for Mars to return to the same constellation, or in this case, back to being close to Antares. Every 15 years or so Mars and Antares are in the sky together, and give or take several months to two will close in on each other as they are currently.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.