This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, January 27, 2023.
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.
Observing Highlight of the Week
Image of comet C/2022 E3 (ZTF) taken by Randy Harrison. The green color seen in the coma of the comet is caused by diatomic carbon. Image credit: Randy Harrison.
Our highlight this week will again be the comet C/2022 E3 (ZTF). Interest in this comet is increasing owing to several articles and news pieces beginning to make the rounds. Likely the rest of January and some of February will continue to focus on updates regarding C/2022 E3 (ZTF). If you would like to revisit past posts regarding the comet, they will stay posted on the Night Sky Update page of our website.
This week, C/2022 E3 (ZTF) will make its closest approach to Earth on February 1, 2023. The comet poses no threat to Earth as when nearest it will be roughly 26 million miles away. As it passes near Earth, the comet will speed through our circumpolar sky showing quite a bit of movement each night. This week C/2022 E3 (ZTF) is passing between the Big and Little Dippers while spending most of the week in the constellation Camelopardalis. As the week comes to an end, C/2022 E3 (ZTF) will be heading towards the bright star Capella in the constellation Auriga.
Magnitude estimates are indicating C/2022 E3 (ZTF) is between 5.5 and 6.0 magnitude. It is now expected that C/2022 E3 (ZTF) will peak around 5.5 magnitude. For most this means the comet will remain a binocular target. Traveling to a dark sky might reveal naked eye views of the comet but if you have any light pollution you will need binoculars.
Weather has not been great this last week so views from St. Louis have been limited. I last saw C/2022 E3 (ZTF) on January 26, 2023 and would put the comet around 6th magnitude. Looking at current forecasts, it appears our next clear night will not be until Monday, January 30, 2023. On this night, the comet will appear about 10.5°east of the North Star. Another complication is the Moon. January 28, 2023, marks first quarter phase for the current lunation. This unfortunately means moonlight will interfere when the comet is brightest. As we wait for clear skies, Sky and Telescope has an excellent article that goes deeper into details about C/2022 E3 (ZTF). It is also another source of maps showing the comets location.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sunrise is at 7:11 a.m. on Friday, January 27 and sunset is at 5:17 p.m. providing us with roughly 10 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 6:49 p.m. this week. For those with a sundial, local noon occurs around 12:11 p.m. this week.
| Day | Sunrise | Sunset | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 27-Jan | 7:11 a.m. | 5:17 p.m. | ||||||||||
| 28-Jan | 7:10 a.m. | 5:18 p.m. | ||||||||||
| 29-Jan | 7:09 a.m. | 5:19 p.m. | ||||||||||
| 30-Jan | 7:08 a.m. | 5:20 p.m. | ||||||||||
| 31-Jan | 7:07 a.m. | 5:21 p.m. | ||||||||||
| 1-Feb | 7:07 a.m. | 5:23 p.m. | ||||||||||
| 2-Feb | 7:06 a.m. | 5:24 p.m. | ||||||||||
| 3-Feb | 7:05 a.m. | 5:25 p.m. | ||||||||||
| 4-Feb | 7:04 a.m. | 5:26 p.m. |
Moon
Moonrise for Friday, January 27 was at 10:44 A.m. and moonset occurs at 12:18 a.m. on the following day. Friday, January 27, the Moon will exhibit a waxing crescent phase with 41% of the lunar disk illuminated. New moon occurs on January 28, 2023, at 9:19 a.m.
International Space Station (ISS) Observing
There are several visible passes of ISS from St. Louis for the week of January 27. They occur during evening 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, January 27
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 01 Feb | -2.7 | 19:19:14 | 10 | WNW | 19:21:46 | 45 | WNW | 19:21:46 | 45 | WNW |
| 02 Feb | -3.8 | 18:30:24 | 10 | NW | 18:33:44 | 69 | NE | 18:35:41 | 23 | ESE |
| 04 Feb | -2.3 | 18:29:24 | 10 | WNW | 18:32:32 | 38 | SW | 18:35:40 | 10 | SSE |
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 5:48 p.m. on January 28, 2023. Credit: Stellarium, EG
Looking southeast at 6:40 a.m. on January 29, 2023. Credit: Stellarium, EG
Mercury
Mercury is currently exhibiting its best morning apparition of the year. The best chance to see it will be about 30 minutes before sunrise. At this time Mercury will be roughly 10° above the southeastern horizon. Mercury reaches greatest western elongation on January 30, 2023.
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. This week, look for Venus in the southwest about 20 minutes after sunset.
Mars
Mars now rises before sunset becoming visible once it is dark. Look for it in the east about 30 minutes after sunset. Mars sets by 3:26 a.m.
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. Jupiter now sets at 9:56 p.m.
Saturn
Now past opposition, Saturn rises before sunset. You can find this giant world in the southwest about 30 minutes after sunset. Saturn will soon be lost to the Sun’s glare as it approaches superior conjunction on February 16, 2023. Saturn sets by 6:37 p.m. Saturn has become increasingly difficult to see. For many this may be our last chance until Saturn returns to the morning sky later this spring.
James S. McDonnell Planetarium
Night Sky Update: January 27 – February 4, 2023