Highlights Of The Waxing Gibbous Moon

The crater Copernicus is one of the moon’s finest and visible in binoculars. A small asteroid excavated the rocky bowl some 800 million years ago. Since then the crater’s walls have slumped to create a series of concentric terraces. Mountain peaks formed of rock that rebounded after the impact are seen the crater’s center. NASA / LRO

Take a look at tonight’s waxing gibbous moon in almost any pair of binoculars tonight and you’re going to see one of its most magnificent craters — Copernicus. Named for Nicholas Copernicus, the Polish astronomer who placed the sun rather than the Earth at the center of the solar system, the crater is 58 miles (93 km) wide and 2.4 miles (3.8 km) deep, twice the depth of the Grand Canyon.

The sun rises at Copernicus nine days after new moon which happens to be tonight (Jan. 4, 2020). Sunrise is one of the most exciting times to view lunar features because the long shadows cast by a low sun (whether moon or Earth) reveal rich textures in the landscape. Solar rays pick out little details in the landscape like knobs and hills, cracks and crevices, and in the case of Copernicus, its terraced inner walls and central mountain peaks.

Copernicus lies along the moon’s terminator tonight (Jan. 4), where the sun is rising at the moon. The right side of the moon is already in sunshine; the remaining portion is still in darkness until the sun rises there as the moon fattens to full. Tonight Copernicus is near the sunrise line, so the low-angled light makes it pop. Your binoculars will also reveal the crater Plato located north of Copernicus. Virtual Moon Atlas

For these you’ll need a small telescope, but binoculars will easily show Copernicus astride the terminator tonight. What a beautiful and rugged ring it is! You’ll also notice that it’s surrounded by a nimbus of mottled light called rays. They formed when rock blasted from the impact 800 million years ago rained back down on the surface and dug up countless smaller craters. Each tiny impact exposed lighter-colored soil beneath the sun-baked surface, the reason the rays look bright.

Use the moon and pair of binoculars to find the planet Uranus tonight. Stellarium

Take some time to explore the moon — binoculars will show many more craters besides Copernicus and Plato. When you feel ready to move on, use the map above to guide you to the planet Uranus. Luna shines only 5° from Uranus tonight which is about equal to the field of view of a typical pair of binoculars. If you place the moon outside the bottom of the field of view, you’ll see three stars in a bent line just above the center of the field. The middle “star” is Uranus. It’s flanked by two true stars both of which are a little fainter than the planet.

The Solar and Heliospheric Observatory (SOHO) took this photo of Jupiter and Mercury from space early this morning, Jan. 4, 2020. Both planets are too close to the sun to see from the ground right now. SOHO hides the sun behind a special occulting disk to block the glare. The fuzzy object between the two planets is the globular cluster M22.  NASA / ESA

Uranus is a cold and distant world 1.8 billion miles (2.9 million km) from the Earth at the moment and currently in the constellation Aries near the border with Cetus the Sea Monster.  I like using bright objects to find fainter ones. The brightest object of all is the sun, but it lights up the atmosphere so much we don’t ordinarily use it to point us to other celestial objects. But if you could view the sun from space today the way SOHO does and use your hand to block its light, you’d spy the planetary duo of Jupiter and Mercury several degrees to the west of our star.