This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, April 16, 2021.
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
Star parties at the Saint Louis Science Center have temporarily been canceled due to recommendations from the CDC regarding COVID-19. All public telescope events are canceled until further notice. As conditions change, we will reevaluate and update this article once public observing events resume.
Observing Highlight of the Week
Constellation Lyra Rising in the Northeast at 10:00 pm
Credit: Stellarium, EG
This week the annual Lyrid Meteor Shower will peak on the night of April 21-22, 2021. Meteor showers are annual events that occur as Earth encounters debris streams left by other objects in the solar system that orbit the Sun. In most cases, the culprit of the debris streams are comets. This is the case for the Lyrids that are caused by debris left by Comet Thatcher C/1861 G1. C/1861 G1 is a long period comet that take about 415.5 years to orbit the Sun. Its last perihelion occurred in 1861 and it will reach its next perihelion in 2283.
Observing meteor showers is simple. The only requirements are clear skies and knowledge of the showers radiant. A meteor shower radiant is the point in the sky that a meteor’s path appears to radiate from. It is not necessary to only observe the radiant, but rather it gives you an idea of where you will see meteors. Meteor showers will be best viewed when the radiant is at its highest in the sky for your location. This typically occurs after midnight.
The radiant for the Lyrids is in the constellation Lyra the Harp. You can find Lyra rising in the northeast by 10:00 p.m. To find Lyra, look for the bright star Vega which will be the brightest star visible above the northeast horizon at 10:00 p.m. The Lyrids will be best viewed after midnight once Lyra is seen higher in the sky.
An additional complication will be the moon phase. On April 21, the Moon will exhibit a waxing gibbous phase with about 64% of the lunar disk illuminated. The Moon will set at 4:01 a.m. and will be less of an issue once it is lower in the western sky. The Lyrids are a moderate meteor shower so visibility will be low if viewed from light polluted skies. The Lyrids are known to produce fireballs so be on the look out for periodic bright meteors.
Meteor showers are one of the most enjoyable and easy astronomical events to observe. It is always best if you go somewhere dark and bring along a nice reclining chair. If you would like to learn more about meteor showers visit www.amsmeteors.org
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sunrise is at 6:23 a.m. on Friday, April 16 and sunset is at 7:39 p.m. providing us with over 13 hours of daylight. Even after sunset, the light from the Sun will dimly illuminate our sky for about 1 hour and 40 minutes. This period is called twilight, which ends around 9:14 p.m. this week. For those with a sundial, local noon occurs around 13:01 p.m. this week.
Day | Sunrise | Sunset |
---|---|---|
2021-04-16 | 6:23 a.m. | 7:39 p.m. |
2021-04-17 | 6:22 a.m. | 7:40 p.m. |
2021-04-18 | 6:20 a.m. | 7:41 p.m. |
2021-04-19 | 6:19 a.m. | 7:42 p.m. |
2021-04-20 | 6:18 a.m. | 7:43 p.m. |
2021-04-21 | 6:16 a.m. | 7:44 p.m. |
2021-04-22 | 6:15 a.m. | 7:45 p.m. |
2021-04-23 | 6:13 a.m. | 7:46 p.m. |
2021-04-24 | 6:12 a.m. | 7:47 p.m. |
Moon
Moonrise for Friday, April 16 occurs at 8:59 a.m. and moonset will occur at 12:12 a.m. the following morning. On Friday, April 16 the Moon will exhibit a waxing crescent phase with 17% of the lunar disk visible. First quarter moon occurs on April 20 at 1:59 a.m.
International Space Station (ISS) Observing
Visible passes of ISS from St. Louis for the week of April 16 occur during morning hours. The best passes this week occur on the morning of April 23. Use the table below for information about this and other visible passes this week.
Catch ISS from St. Louis starting Friday, April 9
Date | Starts | Max. altitude | Ends | |||||||
---|---|---|---|---|---|---|---|---|---|---|
Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
21 Apr | -0.8 | 05:42:51 | 10 | SSE | 05:43:56 | 11 | SE | 05:45:02 | 10 | ESE |
23 Apr | -2.4 | 05:42:37 | 10 | SSW | 05:45:43 | 35 | SE | 05:48:50 | 10 | ENE |
24 Apr | -1.6 | 04:56:04 | 10 | S | 04:58:31 | 20 | SE | 05:01:04 | 10 | E |
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 8:30 pm, April 16, 2021
Credit: Stellarium, EG,
Looking Southeast, at 5:00 am, April 17, 2021
Credit: Stellarium, EG
This week, three naked eye planets are visible. Mars is found high in the west after sunset. Jupiter and Saturn can be found in the southeast before sunrise.
Venus
Venus is starting another evening apparition. It is still a little too close to the Sun to see but Venus should be easy to spot by the start of May shortly after sunset.
Mars
Currently Mars appears as a 1.4-magnitude object that will be visible high in the west about 40 minutes after sunset. Mars sets by 12:29 a.m.
Jupiter
Jupiter is visible in the southeast before sunrise. Jupiter rises at 4:00 a.m. and will be easy to see in the southeast by 5:00 a.m.
Saturn
Saturn has returned to our morning sky. Saturn rises at 3:20 a.m. and will be easy to spot by 4:30 a.m. looking southeast.
James S. McDonnell Planetarium
Night Sky Update: April 16-April 24, 2021