Jupiter joins the evening sky at the right time for stargazers
Jupiter recently had its closest approach to Earth since 1951.
Have you seen that super bright star popping out in the low southeastern sky during evening twilight? That’s no star but rather the big guy of our solar system, the planet Jupiter.
The 88,000-mile-wide planet, named after the king of the gods in Roman mythology, is visible all night long right now and is almost at its closest approach to Earth for 2022. This week Jupiter is a little over 372 million miles from Earth. The bigger picture is that Earth and Jupiter are much closer to each other than average in their respective orbits around the sun.
In late September, Jupiter reached what astronomers call opposition when it was only around 367 million miles away. In fact it was the closest it’s been to Earth since 1951. It’s called opposition because Jupiter and the sun are at opposite ends of the sky, just like a full moon. Earth lies between the sun and Jupiter, as you can see in the diagram. Since they’re at opposite ends of our celestial dome, Jupiter rises at sunset and sets at sunrise. The Jovian giant is prowling across the sky all night.
Earth and Jupiter get into the opposition position every 399 days or about every 13 months. That’s because it takes Earth slightly over 365 days to make one complete orbit of the sun while it takes Jupiter 12 years to make its much larger solar circuit. So, in the one year that it takes Earth to circle the sun, Jupiter has only made it a twelfth of the way around our home star. It takes Earth another month to “catch up” with Jupiter and line up with it and the sun again.
If you have super eagle eyes, there are times when Jupiter looks like it has tiny appendages on either side of it. These are Jupiter’s moons. There’s no way you can visually resolve them with your naked eyes, but a small pair of binoculars or telescope will reveal up to four of Jupiter’s brightest moons. They look like little stars on either side of the great planet. I’ll have much more on Jupiter’s moons and how to keep up with them in an upcoming Starwatch column.
With even a small telescope, you can easily see Jupiter’s moons, and you can also clearly resolve the disk of the planet and some of its cloud bands and zones that stripe the big guy of the solar system. Jupiter is mostly a big ball of hydrogen and helium gas, but methane, ammonia, sulfur, and other gases create the multi-color cloud bands in its outer atmosphere. The two darker cloud bands on either side of Jupiter’s equator are the easiest ones to spot.
When viewing Jupiter with a telescope, the keyword is patience. Most importantly, wait until Jupiter is high enough above the horizon so you don’t have to look through as much of Earth’s blurring atmosphere to see it. Jupiter should be high enough for decent telescope viewing by around 9 p.m. Also, it’s a good practice to take long, continual views through the eyepiece whenever you have your telescope on any of the planets. That will not only give your eyes a chance to get used to the light level within the eyepiece, but you’ll also have a better chance of catching quiet, less turbulent patches of clearer air passing by in Earth’s atmosphere.
Get used to seeing the king of the planets in our night sky, as it will be visible in the evenings well into next year.
Celestial Happening this week: On Friday evening, Oct. 14, 2022, just after 9 p.m. the waning gibbous moon will be to upper left of Mars. Even with the naked eye Mars will have a reddish tinge to it. On Friday night, Mars will be 65 million away but drawing closer and closer to Earth. Stay tuned.
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul and is author of the book, “Stars, a Month by Month Tour of the Constellations” published by Adventure Publications. Send questions to email@example.com .
The Rochester Astronomy Club welcomes new members and puts on public star parties. Their website is rochesterskies.org .