This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, January 13, 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
Position of comet C/2022 E3 (ZTF) from January 15 – 21, 2023. C/2022 E3 (ZTF) is in the constellation Boötes and will be seen heading north. The two constellations highlighted in the image are Hercules and Boötes on the top. Image created using Stellarium.
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 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.
C/2022 E3 (ZTF) is currently found in the constellation Boötes and will remain here through January 22, 2023. Now that it is past perihelion, C/2022 E3 (ZTF) will begin to rapidly head into the circumpolar sky. For the time being, C/2022 E3 (ZTF) remains a morning target as it slowly passes through Boötes. This will change near the end of January but for now set those alarm clocks.
On January 14, 2023, I finally had a chance to track down the comet around 5:00 a.m. To see it, I used both 8×56 and 15×70 binoculars. Due to bright moonlight, I had to use averted vision and motion for my eye to see the comet’s faint coma. Due to interference from moonlight, it was hard to give a magnitude estimate, but it was just bright enough to see in larger binoculars. As the Moon continues to wane this week, seeing conditions will improve making the comet easier to spot. As we head later into the week, I will continue to try and spot it in smaller binoculars. For the time being, telescopes will still provide your best chance to see C/2022 E3 (ZTF).
To find the comet it will be necessary to have a good map of the sky. There are several free tools available but the one I use most is a software called Stellarium. This is free to download which has versions of the software for all platforms. I also recommend the Comet Chasing website as they will update maps of the comets path as needed.
As always, weather conditions are a complication. An excellent resource to track weather conditions at your observing site is cleardarksky.com. Once you set your observing location it will provide an astronomer’s forecast. One of the local astronomy clubs, The St. Louis Astronomical Society, has set up a St. Louis Missouri link on this website. You can find that by searching for St. Louis Clear Sky Chart. According to current forecasts, it looks like Tuesday morning is our next best chance to see C/2022 E3 (ZTF).
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, January 13 and sunset is at 5:01 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 6:36 p.m. this week. For those with a sundial, local noon occurs around 12:09 p.m. this week.
| Day | Sunrise | Sunset | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 13-Jan | 7:18 a.m. | 5:01 p.m. | ||||||||||
| 14-Jan | 7:17 a.m. | 5:02 p.m. | ||||||||||
| 15-Jan | 7:17 a.m. | 5:03 p.m. | ||||||||||
| 16-Jan | 7:17 a.m. | 5:04 p.m. | ||||||||||
| 17-Jan | 7:16 a.m. | 5:06 p.m. | ||||||||||
| 18-Jan | 7:16 a.m. | 5:07 p.m. | ||||||||||
| 19-Jan | 7:15 a.m. | 5:08 p.m. | ||||||||||
| 20-Jan | 7:15 a.m. | 5:09 p.m. | ||||||||||
| 21-Jan | 7:14 a.m. | 5:10 p.m. |
Moon
Moonrise for Friday, January 13 is at 11:32 p.m. and moonset occurs at 11:21 a.m. on the following day. Friday, January 13, the Moon will exhibit a waning gibbous phase with 61% of the lunar disk illuminated. Last quarter moon occurs on January 14, 2023, at 8:10 p.m.
International Space Station (ISS) Observing
There are several visible passes of ISS from St. Louis for the week of January 13. 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 13
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 15 Jan | -3.3 | 18:30:43 | 10 | SSW | 18:33:53 | 41 | SE | 18:34:08 | 40 | ESE |
| 17 Jan | -3.5 | 18:29:57 | 10 | WSW | 18:33:16 | 63 | NW | 18:34:23 | 37 | NNE |
| 18 Jan | -3.7 | 17:41:16 | 10 | SW | 17:44:35 | 71 | SE | 17:47:53 | 10 | NE |
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 6:00 p.m. on January 14, 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. 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.
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: January 13 – 21, 2023