Earlier this morning, Mars and Mercury passed very close to one another low in the eastern sky at dawn. Sunday morning (Sept. 17), they’ll still be just ½° apart and preceded by the star Regulus, planet Venus and the crescent moon. It gets even better on the 18th, when the moon, now sliver-thin, resides like a king on a throne surrounded by his subjects, in this case three planets and Regulus, in a dance line just 11.5° long. Clear skies and a wide open view to the east are all you need to see these beautiful alignments.
Mercury, always a bit elusive, is now brighter than magnitude 0 and easier to find than usual. Look for it about 12° below and left of brilliant Venus starting about an hour to 45 minutes before sunrise. When you see Mercury, much fainter Mars will poke out just to its upper right. Regulus is further up and near Venus, which by the way, will be in conjunction with the star on the 19th (Central time) but closest together for the Americas at dawn on the 20th, when they’ll be ½° apart.
Getting up at dawn isn’t as hard as it used to be in July, when you had to set the alarm for 4 a.m. Now you can roll out around 6!
Did you watch the Cassini finale? What a fantastic mission, and with all the data and photos sent over the past 13 years, astronomers will be busy for a long time to come. Cassini dove into the planet’s atmosphere, sending science data for as long as its small thrusters could keep the spacecraft’s antenna pointed at Earth. Mission control tweaked the probe to get another 30 seconds of life before it burned up like a meteor in Saturn’s atmosphere at 6:55 a.m. CDT at 9.4° N, 53° W.
There were no photos taken during its plunge because pictures take up a lot of space and are slow to transmit; NASA’s priority instead was to gather as much data as possible on the composition of Saturn’s atmosphere. Despite no final image, Cassini took a wonderful timelapse of Saturn’s moon, Enceladus, on September 13 as it set behind the clouds — a fitting farewell postcard.