Great Conjunction of Saturn and Jupiter Observing Guide

Mark your calendars! On Monday evening, December 21, 2020, the winter solstice (the shortest day and longest night of the year in the Northern Hemisphere), a spectacular celestial event will be visible low in the southwestern sky during evening twilight: the “Great Conjunction” of Jupiter and Saturn!

What makes this conjunction extra special is that at their closest, the two largest planets in our Solar System will be just 0.1 degrees apart in the sky (6 arcminutes of angular separation) and will almost appear to touch each other as seen from Earth. To put it into better perspective, that is just 1/5 of a full moon diameter. Now that is too close for comfort!

Every now and then, we may notice other conjunctions taking place in the sky. Planets will pair up with other planets, and sometimes the Moon will meet up with a planet such as Venus, or even a distant star. The term “Great Conjunction” is the pairing of gas giants Jupiter and Saturn. This is a rare event (taking place about every 20 years on average).

It takes Jupiter 12 years to fully circle around the Sun, while Saturn takes much longer—almost 30 years—to do the same. As it works out, Jupiter laps Saturn once every two decades, and this is when a Great Conjunction occurs. However, not every Jupiter/Saturn conjunction is as close as this year’s event due to the slightly different angles between the Earth, Jupiter and Saturn relative to each other. The “Great Conjunction” of December 21 will be an extraordinary exception! They have not been this close together since 1623 (397 years ago).

Viewing Tips:

• Jupiter and Saturn will be easy to locate and be a noticeable pair as there are no other stars in the night sky that can outshine Jupiter. Jupiter will shine at magnitude -2.0, while Saturn will be much dimmer at +0.6. If you are a beginner and unfamiliar with the night sky, a planetarium app for your smartphone can help point the way. Some of the more robust apps like SkySafari and Celestron’s SkyPortal will also let you know what time the planets rise and set.
• Do not wait until December to begin watching Jupiter and Saturn. They are visible now! Take note of their positions and keep track of them as they move closer and closer together in the weeks leading up to their historic conjunction.
• A few days before the conjunction, note where Jupiter and Saturn are located near the southwestern horizon, so you will have an idea of where they will be on the night of December 21. This will enable you to select the best viewing location with a clear unobstructed view of the southwestern horizon.
• Set up early. There will only be a short window to see the event—about two hours.
• On the evening of December 16 and 17, the thin crescent Moon will be joining Jupiter and Saturn in the southwestern sky. Look for an enchanting evening display.
• Use a telescope at about 75x to 100x magnification or more to fit both planets along with their respective moons in the same eyepiece field of view. What a treat it will be to see the two most popular planets together at the same time in the same eyepiece! Please note that because Jupiter and Saturn will be relatively close to the horizon, the view may become somewhat distorted. After all, you will be observing the planets through the thickest part of Earth’s atmosphere.
• If you have access to a binocular or a spotting scope, use it! Any optical aide will enhance the planets for a more memorable viewing experience. Even a small 8x42 or 10x42 binocular will show Jupiter as a disc and reveal its four brightest moons! Unfortunately, the magnification will not be strong enough to reveal Saturn’s rings. Be sure to use a tripod if one is available to help steady the view, or use a table, wall, or automobile hood/trunk to prop up your arms to help minimize any shaking.

• If no optical aide is available, just use your unaided eyes and enjoy the view.
•  Capture this historic moment with your camera! These planets will not be this close again until the year 2080. Because Jupiter and Saturn will be near the horizon, include a foreground subject for a more picturesque composition. Selfies, anyone?

• Once the historic Great Conjunction of Jupiter and Saturn is over, it does not mean you should stop observing. Continue to follow the planets, and you will gradually see them separate and slowly move apart as the nights go on.

While the year 2020 will go down in history as one of the most stressful for most everyone, it will be leaving us on a high note with the Great Conjunction of Jupiter and Saturn. News of this event is already creating quite a stir in the media as people from all over the world are gearing up to witness one of the most impressive planetary gatherings of a lifetime. This is an event that you do not want to miss!