The moon’s getting brighter and brighter as its phase fills out this week. I can tell because it’s easier to spot my black dog on our nightly walk. Instead of blending into the darkness, she’s an inky shape against the moonlit road. Moonlight’s a strange thing. We’ve lost most of our snow cover as the weather has warmed, exposing pale brown and gray grasses in the open fields. But under the illumination of last night’s swelling moon, the fields glowed bright enough as if still covered in snow. I actually looked twice to make sure.
Tonight’s moon has a pleasant surprise in store. A waxing gibbous, it will pass just 1° — your pinkie extended at arm’s length — below Regulus, the brightest star in Leo the Lion. Regulus, a name meaning “little king”, lies just in back of the lion’s front paws.
We call these close alignments of celestial objects conjunctions. They’re pleasing to view with both the naked eye and binoculars. Far below the moon and just one day before opposition, you’ll spot unmistakable Jupiter, now the brightest planet in the evening sky.
Tomorrow, Jupiter reaches opposition, when it’s lined up directly behind the Earth and opposite the sun in the sky. It will rise around sunset, reach its highest point in the sky around 1 a.m. and set the next morning around sunrise. On the 8th, the planet will be closest to the Earth and brightest for all of 2017.
The best views of any planet are when its close, so opposition traditionally marks the time when amateur astronomers make a point to view the planet every clear night we can. Even a small telescope will show its two most prominent “stripes” or cloud belts, called the North and South Equatorial Belts, and the planet’s four brightest moons: Io, Europa, Ganymede and Callisto.
For more observing tips on observing Jupiter, please see my article, Jupiter Close, Bright and Up All Night on Sky & Telescope’s website. Happy moonlight nights!