This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, December 31, 2021.
Information updated weekly or as needed.
Times given as local St. Louis time which is Central Standard Time (CST). For definitions of terminology used in the night sky update, click the highlighted text. If relying on times posted in Universal Time (UT), St. louis is -6 hours when CST.
Public Telescope Viewings
With the changing recommendations from the CDC regarding COVID-19, conversations regarding the return of star parties at the Saint Louis Science Center have begun. We are close to bringing back our public telescope viewings, but a few details still need to be worked out. We will post future updates as we learn more about when we can bring back telescope viewings.
Observing Highlight of the Week
Position of the planets and Moon seen on January 7, 2022, after sunset. Image created using Stellarium.
This week, there are several astronomical events that will keep us busy. The Moon starts a new lunation, Mercury will be at its best for the current apparition, and the Quadrantid meteor shower peaks.
To start, this week marks the end of another calendar cycle. The modern Gregorian calendar is a measure of the cycle of seasons, or what is called a tropical year. A tropical year is 365.242189 days long which is why we use the leap year system. The practice of using an intercalary period roughly every four years is done to keep our calendars in sync with the seasons. Without this system our calendar would be off by 1 day in four years and 25 days in 100 years.
On January 7, 2022, Earth reaches perihelion which is when Earth is closest to the Sun. The far point is called aphelion which occurs on July 5, 2022. These near and far points are called apsides and their occurrence will vary from year to year by a few days. This variance is caused by the Moon’s gravitational impact on the Earth.
The first new moon of 2022 occurs on January 2, 2022, starting lunation 1225. New moon starts the Moon’s synodic cycle which lasts 29.5 days. This cycle is called a synodic month which is what our calendar month is based on. With the start of a new lunar cycle, you can expect to find the Moon in the west after sunset in its waxing crescent phases this week.
Mercury reaches greatest eastern elongation on January 7, 2022, when it will appear roughly 19° from the Sun. Being closer to the Sun, Mercury never strays too far away before it heads back towards the Sun’s glare. This is why Mercury and Venus are only visible after sunset in the west or before sunrise in the east. If you spot Mercury in a telescope on January 7, 2022, it will exhibit a quarter phase.
Mercury is getting easier to see this week, but Venus will be lost to the Sun’s glare. Venus has been found in the west after sunset for most of 2021. That is about to end as Venus will reach inferior conjunction on January 8, 2022. This is when Venus passes between Earth and the Sun. Venus will be seen closer to the Sun each day and will soon be mired in the Sun’s glare. If you try to spot Venus this week, do so with caution. Make sure the Sun has set.
Lastly, the peak of the Quadrantid Meteor Shower occurs on January 3, 2022. The Quadrantids has the potential to be one of the best meteor showers. Some years have seen peak hourly rates of 125 meteors per hour. The challenge with the Quadrantids is it has a very short peak period of about 6 hours. Additionally, the shower’s radiant is best seen around 3:00 a.m. During the peak, the Quadrantids can produce upwards of 125 meteors per hour. Unfortunately, the peak occurs around 3:00 p.m. CST. Average hourly rates are thus expected to be closer to 25 per hour from a dark location.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sunrise is at 7:18 a.m. on Friday, December 31 and sunset is at 4:50 p.m. providing us with roughly 9.5 hours of daylight. Even after sunset, the light from the Sun will dimly illuminate our sky for roughly 1 hour and 30 minutes. This period is called twilight, which ends around 6:25 p.m. this week. For those with a sundial, local noon occurs around 12:03 a.m. this week.
| Day | Sunrise | Sunset |
|---|---|---|
| 2021-12-31 | 7:18 a.m. | 4:50 p.m. |
| 2022-01-01 | 7:19 a.m. | 4:50 p.m. |
| 2022-01-02 | 7:19 a.m. | 4:51 p.m. |
| 2022-01-03 | 7:19 a.m. | 4:52 p.m. |
| 2022-01-04 | 7:19 a.m. | 4:53 p.m. |
| 2022-01-05 | 7:19 a.m. | 4:54 p.m. |
| 2022-01-06 | 7:19 a.m. | 4:55 p.m. |
| 2022-01-07 | 7:19 a.m. | 4:56 p.m. |
| 2022-01-08 | 7:19 a.m. | 4:57 p.m. |
Moon
Moonrise for Friday, December 31 occurs at 4:59 a.m. and moonset will occur at 2:44 p.m. On Friday, December 31 the Moon will exhibit a waning crescent phase with 6% of the lunar disk illuminated. New moon occurs on January 2, 2022, at 12:34 p.m.
International Space Station (ISS) Observing
Visible passes of ISS from St. Louis for the week of December 31 occur during morning hours. The best passes this week occur the mornings of January 5 and 8. Use the table below for information about these and other visible passes this week.
Catch ISS from St. Louis starting Friday, December 31
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 03 Jan | -2.1 | 06:16:08 | 12 | NNW | 06:18:38 | 26 | NNE | 06:21:31 | 10 | E |
| 04 Jan | -1.7 | 05:29:52 | 18 | NNE | 05:30:12 | 19 | NNE | 05:32:40 | 10 | ENE |
| 05 Jan | -3.5 | 06:16:34 | 17 | NW | 06:18:59 | 64 | NE | 06:22:19 | 10 | ESE |
| 06 Jan | -2.8 | 05:30:23 | 37 | NNE | 05:30:40 | 38 | NNE | 05:33:49 | 10 | ESE |
| 07 Jan | -0.7 | 04:44:15 | 15 | ENE | 04:44:15 | 15 | ENE | 04:45:06 | 10 | E |
| 07 Jan | -3.1 | 06:17:11 | 20 | WNW | 06:19:06 | 39 | SW | 06:22:15 | 10 | SSE |
| 08 Jan | -3.7 | 05:31:07 | 69 | S | 05:31:07 | 69 | S | 05:34:11 | 10 | SE |
Magnitude (Mag): The Measure of brightness for a celestial object. The lower the value is, the brighter the object will be.
Altitude (Alt): The angle of a celestial object measured upwards from the observer’s horizon.
Azimuth (Az): The direction of a celestial object, measured clockwise from an observer’s location with north being 0°, east being 90°, south being 180° and west being 270°.
For information about ISS flyovers and other visible satellites, visit www.heavens-above.com
Detailed information regarding all unmanned exploration of our universe, missions past, present, and planned, can be found at Jet Propulsion Laboratories:
The Visible Planets
Looking southwest, at 5:30 p.m. December 31, 2021. Credit: Stellarium, EG
Looking southeast, at 6:30 am, January 1, 2022. Credit: Stellarium, EG
This week, five naked eye planets are visible. Mercury, Venus, Jupiter and Saturn are visible in the southwest after sunset. Mars is still tough to see but it is steadily climbing out of the Sun’s glare in the east before sunrise.
Mercury
Mercury is exhibiting another evening apparition. Those with clear horizons in the southwest will see Mercury about 30 minutes after sunset. Mercury reaches greatest eastern elongation on January 7, 2021.
Venus
Venus is nearing the end of another evening apparition. It will be visible in the southwest as the sun sets. Venus will set at 5:53 p.m. Venus is on its way back towards the Sun’s glare as it approaches inferior conjunction on January 8, 2022.
Mars
A new apparition for Mars has begun. Mars rises at 5:26 a.m. Start looking for Mars around 6:00 a.m. as it clears trees and buildings. Mars will continue to climb out of the Sun’s glare as we see the end of 2021. Mars reaches opposition next year on December 7, 2022.
Jupiter
Look for Jupiter in the southwest as it starts to darken outside. Jupiter sets at 8:49 p.m. and will set about 30 minutes earlier each week. Jupiter reaches superior conjunction on March 5, 2022.
Saturn
Saturn is visible about 20 minutes after sunset in the southwest. Saturn sets at 7:15 p.m. Saturn will reach superior conjunction on February 4, 2022.
James S. McDonnell Planetarium
Night Sky Update: December 31 – January 8, 2022