This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, April 14, 2023.
Information updated weekly or as needed.
Times given as local St. Louis time which is Central Daylight Time (CDT). 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 -5 hours when CDT.
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 May 5, join us indoors in our planetarium theater for “The Sky Tonight”. Showtime is at 7 p.m.
Observing Highlight of the Week
A meteor seen in the sky above the ALMA observatory. As defined by the American Meteor Society, a meteor is the light phenomena which results from the entry into the Earth’s atmosphere of a solid particle from space. Image credit: ESO/C, Malin.
This week the Lyrid meteor shower reaches its peak activity. This is predicted to occur around 01:00 UTC on April 23, 2023, which corelates to 8:00 p.m. CDT, on April 22, 2023. The Lyrid meteor shower is listed as a moderate meteor shower that can produce 10-20 meteors per hour during peak activity. It is always advisable to travel to a dark location to see the most meteors. In urban skies, visibility rates will drop dramatically, but it is a meteor shower worth observing regardless of city lights.
Late winter and early spring are the slow time of they year for watching meteor showers. The Lyrids are one of the better meteor showers during this slow time. One thing the Lyrids are know for is producing bright meteors. Occasionally, some meteors will become brighter than any star or planet visible. These bright meteors are called fireballs.
Most meteor showers are caused by comets with a few being caused by asteroids. The Lyrids are the result of comet 1861 G1 Thatcher. This long period comet orbits the Sun every 415.5 years. It last reached perihelion in 1861 so it will be a while before it returns to the inner solar system. As comets orbit the Sun, they leave behind debris released as the comet heats up. As its ices sublimate, material trapped in the ice is deposited along the comet’s orbital path. If the comet’s orbit is close enough to Earth’s orbit, we pass through this debris leading to a meteor shower. Meteor showers are annual events because we pass through the debris of a given comet at the same time each year.
A meteor shower is identified by its radiant. This is the point in which a meteor appears to emanate from. As Earth moves through a meteor stream, the radiant will drift relative to the background stars. The Lyrid radiant is near the bright star Vega found in the constellation Lyra the Harp.
For those hoping to see the Lyrids, you can start looking northeast around 11:00 p.m. Unfortunately, the Lyrid radiant is just beginning to rise at this time so there will be few meteors to see. As the radiant climbs higher above the horizon, you will have a better chance of seeing meteors. The best views will come after 2:00 a.m. on April 23, 2023.
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sunrise is at 6:26 a.m. on Friday, April 14 and sunset is at 7:36 p.m. providing us with a bit over 13 hours of daylight. Even after sunset, light from the Sun will dimly illuminate our sky for roughly 1 hour and 40 minutes. This period is called twilight, which ends around 9:11 p.m. this week. For those with a sundial, local noon occurs around 1:01 p.m. this week.
There is a hybrid solar eclipse on April 20, 2023. The eclipse begins at 1:34 UTC. Unfortunately, this means we will not see any of the eclipse in St. Louis because for us 1:34 UTC on April 20, 2023, translates to 20:34 CDT on April 19, 2023. The eclipse occurs when it is nighttime for us. This is a good reminder that solar eclipses occur at least twice a year, but they are not always visible where we live. If you would like to learn more about the eclipse on April 19/20, 2023, visit https://www.timeanddate.com/eclipse/solar/2023-april-20
| 14-Apr | 6:26 a.m. | 7:36 p.m. | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 15-Apr | 6:25 a.m. | 7:37 p.m. | ||||||||||
| 16-Apr | 6:23 a.m. | 7:38 p.m. | ||||||||||
| 17-Apr | 6:22 a.m. | 7:39 p.m. | ||||||||||
| 18-Apr | 6:21 a.m. | 7:40 p.m. | ||||||||||
| 19-Apr | 6:19 a.m. | 7:41 p.m. | ||||||||||
| 20-Apr | 6:18 a.m. | 7:42 p.m. | ||||||||||
| 21-Apr | 6:16 a.m. | 7:43 p.m. | ||||||||||
| 22-Apr | 6:15 a.m. | 7:44 p.m. |
Moon
Moonrise for Friday, April 14 is at 3:38 a.m. and moonset occurs at 1:22 p.m. Friday, April 14, the Moon will exhibit a waning crescent phase with 33% of the lunar disk illuminated. New moon occurs on April 19, 2023, at 11:13 p.m.
International Space Station (ISS) Observing
There are a few visible passes of ISS from St. Louis for the week of April 14. They occur during morning hours. These passes are listed below. Use the table below for information about these passes.
Catch ISS from St. Louis starting Friday, April 14
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 20 Apr | -1 | 5:19:08 | 10 | SSE | 5:20:42 | 13 | SE | 5:22:16 | 10 | E |
| 22 Apr | -2.6 | 5:17:29 | 1 | SSW | 5:20:24 | 37 | SE | 5:23:34 | 10 | ENE |
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 west at 8:00 p.m. on April 16, 2023. Credit: Stellarium, EG
Looking East at 6:00 a.m. on April 17, 2023. Credit: Stellarium, EG
This week, four naked eye planets will be visible. Mercury, Venus and Mars are found in the west after sunset. Saturn is now visible in the east about 30 minutes before sunrise.
Mercury
Mercury is visible in the west about 30 minutes after sunset. Mercury will reach greatest eastern elongation on April 11, 2023. Mercury remains visible in the west after sunset through April 20, 2023. After this date it will become increasingly difficult to spot Mercury.
Venus
Venus is now well into its current evening apparition. 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 west about 20 minutes after sunset. Venus sets at 10:59 p.m.
Mars
Mars now rises before sunset, becoming visible once it is dark. Look for it high in the west about 30 minutes after sunset. Mars sets by 1:39 a.m.
Saturn
Saturn is slowly climbing out of the Sun’s glare about 30 minutes before sunrise. For many of us, Saturn may still be too low to spot due obstruction along the horizon. 30 minutes before sunrise, Saturn will appear roughly 10° above the horizon.
James S. McDonnell Planetarium
Night Sky Update: April 14 – 22, 2023