Happy New Year!
I'm afraid I have to start this newsletter with a sad announcement: I intend to put this newsletter on a temporary hiatus. I just agreed to teach a math class at the local community college, and although it is only one class, it will be my first college class in 20 years, and I'll probably do some tutoring as well, and all in all I expect it to take a huge chunk of my time. And to be honest, I'm also feeling a bit worn out. I think I could use a break from astronomy for a little while.
My intention is to just focus on math for the next few months and to return to astronomy next summer. I plan to resume the newsletter in May or June, and I also hope to publish three new video courses by the end of the summer. I've drafted the outlines already —Seasons, Latitudes, and Sundials; The Moon; and Eclipses, and Spheres in Space — and I think I can record and publish at least two of them, and hopefully all three, before the academic year begins next fall. These three new courses, alongside my existing constellations course, should make a fairly complete astronomy curriculum for kids. Maybe then I can take a vacation.
Before I leave you for a few months, I wanted to give you an overview of what's coming up in the sky between now and next summer. There is one thing I definitely don't want you to miss — the lunar eclipse on May 15. For early risers, there will also be lots of planetary activity in the coming months over "rosy-fingered dawn," as the poet Homer used to say. We have had several planets decorating the sunset skies for months now, but they will all leave (if they haven't already), and the planets will almost exclusively decorate the pre-dawn skies for the next year or so. If you are interested in meteor showers, springtime is pretty thin on those: the next two will be the Lyrids in April, and the Aquariids in May.
Perhaps this is a good time for a quick review of the on-going characteristic behavior, or "synodic cycles" of each of the planets in the sky:
Mercury is stuck close to the sun, and appears low over the sunrise or the sunset, alternating between them every couple of months. (It was probably named after Mercury because it is so speedy.) The migration from sunset to sunrise happens pretty quickly, while the reverse migration from sunrise to sunset happens more slowly. Currently, Mercury is racing from the sunset scene to the sunrise scene, and it will appear low over the sunrise in mid and late February. It will appear low over the sunset again in late April and early May, and then it will be back over the sunrise in mid and late June.
Venus is also stuck near the sun, but not as closely. So it also alternates between sunrises and sunsets, but it is normally much brighter and higher over the horizon than Mercury. Venus alternates between being the brilliant and beautiful "Evening Star" decorating the sunsets, and the "Morning Star" decorating the sunrises. (It was probably named after the goddess Venus because it is so beautiful.) Very recently it passed the sun on its way from the sunset to the sunrise, and it is already rising quickly over the sunrise. It will become the "Morning Star" in February, March, and April, and then start a very slow descent back into the sunrise through the summer.
Mars has the most erratic behavior of all of the planets. It speeds up and slows down and sometimes goes backwards, and it is normally fairly dim, but has dramatic episodes of brightening, almost as if it were becoming angry every couple of years. For this, and for its distinct red color, it was named after the God of War. Mars is currently fairly dim and low over the sunrise, and it will very gradually climb higher over the sunrise for most of the next year. (The wild behavior occurs at "opposition", which is the event that inaugurated this newsletter in October of 2020, and which will happen again next December. Mars will become very angry again next Christmas.)
Jupiter and Saturn have perhaps the most "normal" or "regular" behavior. They wander in slow circles around the zodiac, creeping slowly from constellation to constellation, and taking a bit more than a year to complete the cycle. (They also have unusual behavior near opposition, as Mars does, but the effects are much more subtle. Mercury and Venus, being trapped near the sun, are never at opposition.) Jupiter is almost as bright as Venus, but unlike Venus, it is not trapped near the sun and can appear high in the sky in the middle of the night, like an imperious god looking down on his domain. Perhaps this is why it was named after the ruler of the Olympians. Saturn is considerably dimmer than Jupiter, and slower. It was probably named after the God of Time because it is so slow. (The Greek name for the Roman god Saturn was "Kronos", as in "chronology" and "chronometer.") Jupiter has been fading into the sunset, and will continue to sink towards the horizon through February, reappearing over the sunrise in late March. Saturn hasn't quite passed the sun yet, but it is probably already too close to the sun and too low in the sunset haze to be seen. It will reappear dimly over the sunrise in April.
After Jupiter finally vacates the sunset in February, the sunsets will remain empty of planets until late 2022 … except for a low and brief appearance by Mercury over the sunsets in April and May.
The morning sky is where all of the planetary action will be for most of the next year. Mercury, Venus, and Mars will appear together over the sunrise for most of February. In March, Mercury will sink back towards the horizon, but will be replaced by Saturn, and then Jupiter will join the scene as well near the end of March. These four — all of the visible planets except Mercury — will hang out in the morning skies for the rest of the spring and into early summer, with Mercury joining them again in June. In mid-June, all five visible planets will be present in the morning skies.
While you wait (I hope) for my return, if you want a personalized guide to the constellations and the planets for any date and time as seen from any location on earth, I recommend the software Stellarium. It's free, and the learning curve is not long.
The Lunar Eclipse of May 15-16
If you are making an astronomical calendar, I'd emphasize this event. This will be a fairly deep total lunar eclipse, best seen from South America or the eastern half of North America. The western half of North America will miss the beginning of the eclipse, but then the sun will set in the west and the moon will rise in the east, and the end of the eclipse will be visible as the moon rises in the eastern sky. Europe and Africa will see the beginning of the eclipse, as the moon descends in the west before the sun comes up, but then the moon will set and the sun will rise and the eclipse will finish with the moon below the western horizon. Asia and Australia will miss the eclipse completely, although New Zealand will be able the catch the final stages.
As with all lunar eclipses, I recommend reminding yourself of a few things while you are watching. Notice that the sun and moon are on opposite sides of you … and thus on opposite sides of the earth … while the event is happening. (This is especially apparent if the eclipse is in progress while the moon rises or sets, which also means while the sun sets or rises.) This is your most important clue that the dark thing covering the moon is the earth's shadow. Also ask yourself: "What is the shape and size of that shadow?"
For more eclipse-observing details, and especially for timetables for any city, I like Time and Date.
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With this, I want to say thanks for being a subscriber, and I hope you'll stick around for a few months while I take my temporary break from astronomy.