Dual Planetary Conjunctions!

Sky-watchers will have a unique opportunity to see two conjunctions of bright planets this month—one in the evening sky after sunset and the other in the morning sky before dawn. Both are showstoppers, but the one before sunrise will be quite spectacular and definitely worth the effort to rise early that day.

Planetary conjunctions are always fascinating sights for observers, as two worlds slowly draw close together over a period of nights and in some cases come so near to each other that they appear to be nearly in contact to the unaided eye. (In actuality, they are separated by many millions of miles in space.) The evening pairing involves Mars and Saturn, visible in the southwestern sky after sunset. They begin August about a dozen degrees apart with Mars to the lower right of the ringed planet. Mars moves closer to Saturn for most the month, finally passing under it from the 23rd to the 26th at which time they will be just 3.5 degrees apart. They will then easily fit within the field of view of binoculars (and just barely within the 3.5 degree, 16x low-power eyepiece field of the Astroscan telescope.).

There will be two other objects in the field of play around these planets this month. The bright blue-white star Spica appears low and to the right of Mars, contrasting nicely with its ruddy color. And much closer to the two planets will be the wide double star Alpha Librae, which can be split in binoculars and will offer a nice sight in the Astroscan.
A much closer and far more spectacular conjunction involves the two brightest planets—Venus and Jupiter—in the predawn sky. Look above the east-northeastern horizon about half an hour or so before sunrise. Early in August, Venus appears there all by itself. But by mid-month Jupiter has risen to meet it. On the morning of the 18th, they will close to within just 0.3 degree of each other! To the unaided eye, they will appear to be nearly touching, while the view in binoculars and telescopes will be truly stunning! And here, any telescope having a low-power field of view of 1 degree will easily encompass the pair. After the 18th, Jupiter continues to rise higher in the sky, moving away from Venus to its upper right. Due to atmospheric turbulence so near the horizon, it unlikely that you will be able to make out the characteristic telescopic features of either planet—the phase of Venus or the cloud belts and satellites of Jupiter. But you may get lucky, so certainly be alert to them.

In closing, August is Perseid Meteor Shower month. The display peaks on the late night of the 12th to 13th, but a waning gibbous Moon will brighten the sky and greatly reduce the number of shooting stars seen.

— James Mullaney
Former assistant editor at Sky & Telescope magazine & author of nine books on stargazing. His latest, Celebrating the Universe!, is available from HayHouse.com.