Home»Gallery»Portola Valley Ranch, Windy Hill, Etc.»12/15-22/2020 The Great Conjunction of Jupiter and Saturn»12/15-19/2020 Jupiter, Saturn and the Moon after Sunset

In recent days my focus has shifted from our immediate environment: Frog Pond, Coal Mine Ridge, seasons, birds – to the celestial. Yes, even from here we can see the stars and the planets.

A special event is approaching on December 21: another “Great Conjunction”, when Jupiter passes Saturn in our night sky. The last one this close was on July 16, 1623 -- but this was close to the Sun from here, and hard to see in the Northern Hemisphere. So let's remember back to March 4, 1226, when the two planets were closer and more-easily visible from the Earth -- in the morning, before dawn. Really close Great Conjunctions tend to come every 400 years or so -- though stay tuned for the morning of March 15, 2080 for another one this century.

I have a wonderful view of the planets and Moon from here in Portola Valley, California. The new Moon, just a sliver, at the horizon at sunset — then night after night, rising up past the two planets, gradually growing from a sliver to a fatter crescent. By now, December 19, the Moon (our Moon, not the generic moon of our Solar System) is way above the planets, hanging much longer in the evening darkness.

The planets — Jupiter and Saturn — grow ever closer, each night. On Dec. 21, they are predicted to appear as one (to the naked eye).

Regardless of its relative rarity, it is cool to see them moving ever closer, night by night. Yes, I do plan to go outside tomorrow eve — with my camera, just for fun. (Though there are many better photographers with better gear, who will capture more spectacular images, I am sure. Many places will be able to see this, clouds permitting.)

Here are a few photos of the lead up to this great event. Taken from Portola Valley Ranch, California with a hand-held camera. You can even see the moons of Jupiter, moving around our sister planet – in different configurations a few days apart!

Here is how to see the Great Conjunction from where you are – if the sky is clear:
1. Go to a place you can see the sun set on the horizon. From Portola Valley, look for a good view of sunset over Skyline. But stay away from crowds .
2. As it gets darker, note the waxing Moon. Keep an eye out for the first star.
3. There they are! Bright planets (or single “planet”, as seen tomorrow eve.) Fairly low over the horizon, in the direction of sunset.
4. Enjoy. Binoculars might help. With a telescope (or even my camera!), you can see some of the moons of Jupiter. A better telescope would show you Saturn in all its glory, rings, moons, and all. All mixed up together as seen from here.

Don’t just watch for one night. The drama plays out over many nights. The stately procession of the heavens; the Moon moving up, its sliver of light getting larger as its sun-facing side turns toward us. Jupiter and Saturn moving past each other, kissing on the way by. The stars, wheeling in the sky, gradually showing a different pattern as the Earth orbits the Sun. Winter Solstice!!

Helen points out that you can find these planets between the Moon and the point where the Sun has just set. That is, in the Plane of the Ecliptic. Music of the Spheres: all angular momentum in our Solar System points in roughly the same direction. The planets around the Sun are in (almost) the same plane. Their axes of rotation each point in roughly the same direction: they rotate the same way. (Uranus is an exception regarding axis of rotation; our former "planet" Pluto is out of the plane as well as having a different axis of rotation. Perhaps Pluto was captured, not formed with the rest of our current planets??) The Earth's rotation axis is a little further off than that of some of the other planets -- did we have a big collision at the creation of our Moon? And most moons and rings are also rotating in about the same direction. You can see that Jupiter's moons point roughly toward Saturn as they approach each other. All angular momentum, pointing in about the same direction, toward our North Star. (Does anyone know about the angular momentum of the *Galaxy*?)

So go outside. Watch the Moon, Jupiter, Saturn, the other planets, and the stars. Lie down on the Earth on your back, spread your arms wide, and feel the Earth carry you as it turns. The North Star stays in its place on the axis, as we wheel and turn.