January 21, 2023: The lunar New Year starts at the New Moon. One evening before their conjunction, Venus closes in on Saturn. Two famous triangles are visible after sundown.
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 7:13 a.m. CST; Sunset, 4:52 p.m. CST. Check local sources for sunrise and sunset times for your location. Times are calculated from the U.S. Naval Observatory’s MICA computer program.
Jupiter’s Great Red Spot’s transit times, when it is in the center of the planet in the southern hemisphere: 6:55 UT, 16:51 UT; Jan. 22, 2:47 UT. Convert the time to your time zone. In the US, subtract five hours for EST, six hours for CST, and so on. Use a telescope to see the spot. Times are from Sky & Telescope magazine.
The moon has been a reliable timepiece for many cultures. The earliest Egyptian calendar was a combination of seasons, moon phases, and appearances of stars. Jewish and Muslim religious calendars are founded on the moon. Traditional Asian cultures use the moon to signal the New Year. The dates vary from January 21st to February 20th.
The New Year typically begins at the second New moon phase following the winter solstice. In the western hemisphere, this month’s New moon phase occurs today at 2:53 p.m. CST. In Asia, specifically in Beijing, China, the time is January 22nd, 4:53 a.m. China Standard Time. Calendars show the 22nd as the beginning of the New Year.
Frequently in North America, the Chinese symbolism and names are used in the popular culture, perhaps from the large populations of Chinese immigrants and their descendants. Each year is named by one of the characters in the Chinese Zodiac. The next animal in the circle is the rabbit. So, 2023 is the Year of the Rabbit on the calendar.
Countries across the region have various traditions and names for their new year. Commonly, the day is known as the Lunar New Year or the Chinese New Year. However you celebrate, Happy New Year!
Summaries of Current Sky Events
Here is today’s planet forecast:
Forty-five minutes before sunup, Mercury – the lone bright planet in the sky this morning – is nearly 7° up in the southeastern sky and nearly 30° to the lower left of Antares – the brightest star in Scorpius.
Mercury is nearing its greatest separation from the sun – known as the greatest elongation – on the 30th. We observe the planet swinging from side to side around the sun, orbiting the central star in only 88 days and passing between Earth and the sun every 116 days. When the planet reaches the farthest point in its orbit from the sun seen from Earth, the angle with our planet at the vertex, is known as the greatest elongation or angle. This year the greatest angle occurs on August 27 with a value of 27.4°.
Geometrically, the greatest elongation of either Mercury or Venus occurs when the line from Earth to the planet is tangent to the planet’s imaginary orbit – assuming a circular path. Notice on the accompanying chart that Venus is on the evening part of the diagram, while Mercury is on the morning section. Additionally, notice that the line from Earth to Venus is not yet tangent to the Venusian orbit. That does not occur until June 4.
For those wanting to check out the geometry further for a planet at greatest elongation. If Earth’s distance is known or assumed, how can you calculate the distance of Mercury or Venus from the sun, knowing or measuring the greatest elongation? Check back on January 29th.
Mercury’s orbit is the most non-circular orbit of the eight largest planets. The planet’s smallest greatest elongation this year is 17.9° on September 22nd, when it is a few days from its perihelion or closest point to the sun.
One evening before the Venus-Saturn conjunction, find Venus less than 10° above the west-southwest horizon at 45 minutes after sundown. Dimmer Saturn is 1.1° to the upper left of the Evening Star. They appear to be close together in the sky, but they are millions of miles apart in space.
Tomorrow evening Venus passes 0.4° to the lower left of the Ringed Wonder. In two nights, a lovely crescent moon joins them.
Back to this evening, bright Jupiter, about halfway up in the south-southwest, is above the imminent conjunction and about 40° to the upper left of Venus. The Jovian Giant is the next bright target for Venus. Their conjunction is March 1st.
Mars is in the east-southeast at this hour, but wait a little longer for the background stars to appear. An hour after sundown, it is nearly two-thirds of the way up in the sky in front of Taurus, with its bright star Aldebaran. The Red Planet is moving eastward passing the star on the 30th. Tonight, the separation is 8.4°.
The Pleiades, a star cluster over 8° to the upper right of Mars, may catch your eye. Use a binocular to look closely at the blue-white stars.
Turn the binocular westward and look at Venus and Saturn against the starfield. Venus’ nightly eastward steps have been noticeable against this starfield as it overtakes Saturn. Tonight, it is nearly between Deneb Algedi and 45 Capricorni (45 Cap on the chart). It is 1.0° to the upper right of the former and 0.5° to the lower left of the latter. The separation from Venus to 45 Capricorni is a little larger than the Venus-Saturn gap tomorrow night.
At one hour after sundown, look for the Winter Triangle and the Summer Triangle simultaneously. In the east-southeast, below Mars and Taurus closer to the horizon, Sirius, Procyon and Betelgeuse make the Winter Triangle. Betelgeuse is part of Orion, an easy constellation to pick out because of the three belt stars of nearly equal brightness that line up.
At this hour farther westward, the Summer Triangle, Vega, Altair and Deneb, are low in the western sky. Look for this view of two triangles during the next several evenings, before Altair disappears from view. The Summer Triangle is in the morning sky before sunrise, to the upper left of Mercury in the east-northeast.
At 8:47 p.m. CST, Jupiter is about 15° above the west-southwest horizon from Chicago, not a good spot to view the Great Red Spot at center stage. Sky watchers farther westward with telescopes see the planet higher in the sky and in clearer air. The window for good view of this feature and other atmospheric activity is quickly closing, for Jupiter is starting the sky farther westward and closer to the horizon each evening.
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