This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, December 30, 2022.
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
As part of the Saint Louis Science Center’s First Fridays, weather permitting, the St. Louis Astronomical Society and the Science Center will set up a number of telescopes outdoors and be on-hand to answer your questions. Telescope viewing begins once it is dark. Regardless of the weather on February 3, join us indoors in our planetarium theater for “The Sky Tonight”. Showtime is at 7 p.m.
*** There will not be a First Friday in January 2023. ***
Observing Highlight of the Week
Winter sky seen from Pokljuka Forrest. Image credit: Dreamy Pixel.
As we look forward to 2023, there are several astronomical events worth taking note of. A solar eclipse, possible naked eye comet and two of the best meteor showers will be free of moonlight. These and several other points of interest will keep us busy in 2023.
For the first few months, we can enjoy views of Saturn and Jupiter in the early evening, but we eventually lose them to the Sun. Saturn reaches superior conjunction in February and Jupiter does the same in April. After superior conjunction, both planets will become visible again in the morning before sunrise as they start another apparition. Mars will remain visible through November when it reaches superior conjunction. Venus is starting an evening apparition and will remain visible in the west after sunset until August when it reaches inferior conjunction on August 13, 2023. Mercury will exhibit several apparitions in 2023 with the best occurring in January and August. The apparition occurring in January is a morning apparition so look for Mercury in the east before sunrise. The apparition in August is an evening apparition so you will find Mercury in the west after sunset. The four outer planets all reach opposition in the last half of 2023. Opposition for Saturn is in August, Neptune is in September and Jupiter and Uranus are in November.
The Moon is always a good target to view no matter the phase. The lunar phase cycle lasts roughly 29.5 days which is a synodic month. Each month, we will see the Moon pass through the zodiac constellations approaching each planet as it completes the cycle. Each month typically has one full moon that in the past was given a name to indicate the time of year. Names like the Full Thunder Moon or the Full Cold Moon are a product of when the Moon was used to keep time. Another name you will hear next year is Blue Moon. Blue Moons occur in years that have 13 full moons. This is possible because our calendar month is on average 30 days long while the synodic month is only 29.5 days. Blue Moons come in two types, seasonal and monthly. Seasonal Blue Moons occur when a season has four full moons, and a monthly blue moon occurs when a month has two full moons. A monthly Blue Moon occurs next year on August 30/31, 2023. The variance in dates is due to time zones. The moment of full moon in St. Louis occurs at 8:36 p.m. on August 30, 2023.
Four eclipses occur in 2023; two are lunar and two are solar. Unfortunately, we will only see one of these from the St. Louis area. On October 14, 2023, an annular eclipse occurs that will be visible throughout the Americas. The path of annularity is only visible along a narrow path while those outside of this path will see various percentages of the Sun partially eclipsed. Annular eclipses are similar to total solar eclipses in that the Moon will pass completely in front of the Sun. The difference between annular and total is determined by the Moon’s distance from Earth. The Moons orbit is not a perfect circle but rather is an ellipse. It is near circular with a mean eccentricity of 0.0549, but it remains that the Moon has a near and far point in its orbit called perigee and apogee. When the Moon is near apogee, it looks a little smaller than the Sun while at perigee it looks about the same size. These differences in apparent size are what determine if we see a total or annual solar eclipse. Because the Moon looks a little smaller near apogee, when the Moon passes in front of the Sun on October 14, 2023, it will not totally obscure the solar disk. Instead, viewers who travel to the path of annularity, will see a thin ring of the Sun unobscured. This ring of light is called an annulus. To see annularity, you will have to travel to parts of Texas, New Mexico, Arizona, Colorado, Utah, Nevada, California and Oregon. In St. Louis, the eclipse will have a magnitude of 0.637 which means we will see a little over half of the Sun obscured by the Moon. The last annular eclipse seen in St. Louis was on May 10, 1994. You can learn more about the October 14, 2023, eclipse and where to view it from at https://www.timeanddate.com/eclipse/solar/2023-october-14
2023 like all years will have lots of meteor showers to look out for. The IAU’s Meteor Data Center lists 966 meteor showers but only 112 are well established. Of these there are only 9 meteor showers listed as major meteor showers. It is these nine that give urban viewers the best chance to see meteors. The table below lists the nine best meteors showers each year, their activity period, peak date and how many meteors you can expect to see during peak activity from a dark location (ZHR). Always remember, the information regarding meteor showers is relevant to a dark location. Hourly visibility rates will change drastically depending on light pollution and moon phase. The two best meteor showers in 2023 will be the Perseids in August and the Geminids in December. These showers will be good this year due to little interference from moonlight. Sky and Telescope has an excellent article that explores the meteor shower outlook for 2023. You can find the article at https://skyandtelescope.org/astronomy-news/the-best-meteor-showers-in-2023/
| Shower | Activity Period | Maximum | Radiant | Velocity | r | Max. | Time | Moon | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Date | S. L. | R.A. | Dec. | km/s | ZHR | |||||
| Quadrantids (QUA) | Dec 26-Jan 16 | 2022-01-04 | 283.3° | 15:20:00 | +49.7° | 40.2 | 2.1 | 120 | 500 | 13 |
| Lyrids (LYR) | Apr 15-Apr 29 | 2022-04-22 | 032.4° | 18:10:00 | +33.3° | 46.8 | 2.1 | 18 | 400 | 2 |
| eta Aquarids (ETA) | Apr 15-May 27 | 2022-05-05 | 046.2° | 22:30:00 | -01.1° | 65.5 | 2.4 | 60 | 400 | 15 |
| Southern delta Aquarids (SDA) | Jul 18-Aug 21 | 2022-07-31 | 127.6° | 22:42:00 | -16.3° | 40.3 | 3.2 | 20 | 300 | 13 |
| Perseids (PER) | Jul 14-Sep 01 | 2022-08-13 | 140.0° | 03:13:00 | +58.0° | 58.8 | 2.6 | 100 | 400 | 27 |
| Orionids (ORI) | Sep 26-Nov 22 | 2022-10-21 | 207.5° | 06:21:00 | +15.6° | 66.1 | 2.5 | 23 | 500 | 7 |
| Leonids (LEO) | Nov 03-Dec 02 | 2022-11-18 | 236.0° | 10:17:00 | +21.6° | 70 | 2.5 | 15 | 500 | 5 |
| Geminids (GEM) | Nov 19-Dec 24 | 2022-12-14 | 262°0 | 07:34:00 | +32.3° | 33.8 | 2.6 | 120 | 100 | 2 |
| Ursids (URS) | Dec 13-Dec 24 | 2022-12-22 | 270°5 | 14:36:00 | +75.3° | 33 | 3 | 10 | 500 | 10 |
Lastly, the comet C/2022 E3 (ZTF) is poised to make its closest approach to Earth on February 1, 2023. When it is nearest Earth, the comet is expected to become 4th magnitude placing it within naked eye visibility. At the time of closest approach, C/2022 E3 (ZTF) will appear in the constellation Camelopardalis. This constellation is circumpolar so the comet will visible all night in the north. Keep in mind that magnitude predictions for comets are just predictions, the comet does not always perform as the models indicate. The last half of January and the month of February will be the best time to try and find C/2022 E3 (ZTF). Planetarium software such as Stellarium are great tools to keep track of comets and other objects in the sky.
2023 has several astronomical events to look forward to. There are several resources online that you can check throughout the year to see what is coming up next. In-the-sky.org, and Heavens Above are two website I frequent throughout the year. If you visit either of these websites, make sure your viewing location is set to where you are before getting times. Also keep in mind timings are often posted in Universal Time (UT).
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 30 and sunset is at 4:49 p.m. providing us with roughly 9.5 hours of daylight. Even after sunset, light from the Sun will dimly illuminate our sky for roughly 1 hour and 30 minutes. This period is called twilight, which ends around 6:24 p.m. this week. For those with a sundial, local noon occurs around 12:03 p.m. this week.
| Day | Sunrise | Sunset |
|---|---|---|
| 2022-12-30 | 7:18 a.m. | 4:49 p.m. |
| 2022-12-31 | 7:18 a.m. | 4:49 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. | 4:54 p.m. |
| 2022-01-07 | 7:19 a.m. | 4:55 p.m. |
Moon
Moonrise for Friday, December 30 is at 12:17 p.m. and moonset occurs at 1:22 a.m. on the following day. Friday, December 30, the Moon will exhibit a waxing gibbous phase with 60% of the lunar disk illuminated. Full moon occurs on January 6, 2023, at 5:08 p.m. This is the first of 13 full moons in 2023.
International Space Station (ISS) Observing
There are several visible passes of ISS from St. Louis for the week of December 30. They occur during morning hours. The best passes for this week are listed below. Use the table below for information about these passes.
Catch ISS from St. Louis starting Friday, December 30
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 03 Jan | -3.7 | 06:40:13 | 10 | NW | 06:43:35 | 78 | NE | 06:46:55 | 10 | SE |
| 04 Jan | -2.9 | 05:53:51 | 27 | NNW | 05:55:17 | 44 | NE | 05:58:30 | 10 | ESE |
| 06 Jan | -3.7 | 05:54:26 | 41 | WNW | 05:55:22 | 61 | SW | 05:58:39 | 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 south at 5:30 p.m. on January 1, 2023. Credit: Stellarium, EG
Looking west at 2:30 a.m. on January 2, 2023. Credit: Stellarium, EG.
This week, four naked eye planets are visible. Mars rises in the early evening and is visible most of the night. Jupiter and Saturn rise before sunset and will be visible once it is dark. Venus is visible in the west about 20 minutes after sunset.
Venus
Venus is climbing out of the Sun’s glare as it starts another an evening apparition. Once high enough above the horizon, Venus will be a bright target in the west after sunset until August 2023 when it approaches inferior conjunction.
Mars
Mars now rises before sunset becoming visible once it is dark. Look for it in the east about 30 minutes after sunset.
Jupiter
Now past opposition, Jupiter will be visible about 30 minutes after sunset. Jupiter reaches superior conjunction on April 11, 2023. As we progress towards this date, we will see Jupiter slowly wander towards the Sun.
Saturn
Now past opposition, Saturn rises before the Sun sets. You can find this giant world in the south about 45 minutes after sunset. Saturn is still a fine target though telescopes and will be a highlight of the evening sky for the rest of the year.
James S. McDonnell Planetarium
Night Sky Update: December 30, 2022 – January 7, 2023