This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, June 19, 2020.

Information updated weekly or as needed.

Times given as local St. Louis time (CDT).  For definitions of terminology used in the night sky update, click the highlighted text.

For now, star parties at the Saint Louis Science Center have 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.

The Sun and Moon


The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA

Sunrise is at 5:37 a.m. on Friday, June 19 and sunset is at 8:29 p.m. providing us with about 15 hours of daylight. Even after sunset, the light from the Sun will dimly illuminate our sky for roughly 2 hours. This period is called twilight, which ends around 10:27 p.m. this week. For those with a sundial, local noon occurs around 1:03 p.m. this week.

DaySunriseSunset
2020-06-19 5:37 a.m.8:29 p.m.
2020-06-20 5:37 a.m.8:29 p.m.
2020-06-21 5:37 a.m.8:29 p.m.
2020-06-22 5:37 a.m.8:29 p.m.
2020-06-23 5:38 a.m.8:29 p.m.
2020-06-24 5:38 a.m.8:29 p.m.
2020-06-25 5:38 a.m.8:30 p.m.
2020-06-26 5:38 a.m.8:30 p.m.
2020-06-27 5:39 a.m.8:30 p.m.

Summer Solstice 2020

The summer solstice for 2020 occurs on June 20 at 4:43 p.m. officially marking the beginning of summer. After June 20 days will grow shorter as the Sun gets lower in the sky each day. You can observe this behavior yourself by measuring the length of a shadow at local noon. The easiest way to do this is to find a nice sunny location and put rod into the ground. The rod acts as a shadow caster or what is called a gnomon.  Each day measure the rod’s shadow at local noon, and you will see the shadow gets longer until we reach the winter solstice in December. In ancient times astronomers observed the behavior of the Sun to keep time, know when to plant and harvest crops and to guide cultural behaviors.

June 21, 2020 Annular solar eclipse (not seen in St. Louis)

An annular solar eclipse occurs on June 21 but sadly it will not be visible from St. Louis. The annular eclipse will be visible in parts of China, India, Saudi Arabia, and parts of Africa.  Solar eclipses only occur during new moon and when the moon is crossing the plane of the ecliptic. The next solar eclipse visible from St. Louis is on October 14, 2023.  We will only see a partial eclipse, but parts of the country will see an annular eclipse.

Moonrise for Friday, June 19 occurs at 4:23 a.m. and moonset will occur at 7:09 p.m. On Friday, June 19 the Moon will exhibit a waning crescent phase with about 2% of the lunar disk illuminated. New moon occurs on June 21 at 1:42 a.m.

International Space Station (ISS) Observing

Credit: NASA

Visible passes of ISS from St. Louis for the week of June 19 occur during morning hours. The best of these occurs on the morning of June 27. Use the table below for information about this and other visible passes of ISS.

Starlink 9 is scheduled to launch at 4:58 p.m. on Tuesday, June 23. This could change depending on launch conditions. Live views of the launch should be available online through the live SpaceX streaming channels. Soon after a Starlink launch there are opportunities to see trains of satellites pass overhead. For those that have not seen one of these satellite trains they are impressive to see. Visit www.heavens-above.com for more information.

Catch ISS from St. Louis starting Friday, June 19

Date Starts  Max. altitude  Ends  
TimeAlt.Az.TimeAlt.Az.TimeAlt.Az.
25 June-1.8 04:51:1610S 04:53:5522SE 04:56:3410E
26 June-1.2 04:04:4010SSE 04:06:1012SE 04:07:3910ESE
27 June-3.7 04:51:2811SW 04:54:3671SE 04:57:5710NE

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:

http://www.jpl.nasa.gov/

The Visible Planets


Looking South, at 12:00 am, June 20, 2020
Credit: Stellarium, EG


Looking East and South, 5:00 am, June 20, 2020
Credit: Stellarium, EG

This week, four naked eye planets are visible in the morning. Jupiter and Saturn rise in the evening but are better seen after midnight. Look for them rising in the southeast and after midnight they will be in the south. Mars will be best seen in the southeast a few hours before sunrise and Venus will be low to the east just before sunrise.

For those tracking Jupiter and Saturn as they approach their great conjunction later this year, the two gas giants currently appear about 5.5° apart in the sky. Jupiter appears to be moving away from Saturn right now due to retrograde motion. This is all an illusion caused by Earth passing by slower moving Jupiter. Saturn has also started retrograde motion. If you keep watching these planets as 2020 progresses, you will see some interesting behaviors that inspired early astronomers to track the skies.

Venus

Venus has begun another morning apparition. After months of seeing Venus in the west after sunset Venus is now visible in the east before sunrise. Venus will clear most trees and buildings in the east about 30 minutes before sunrise. Venus remains a morning object until March 26, 2021 when it reaches superior conjunction.  Venus reaches maximum western elongation on August 12, 2020.

Mars

The red planet rises around 1:08 a.m. and will be high enough to see in the southeast by 2:00 a.m. Opposition for Mars occurs on October 13, 2020. As we head towards this date Mars will appear brighter and larger through a telescope improving surface details. Surface features are already visible when viewing conditions are favorable.

Jupiter

The king of the planets is rising around 10:07 p.m. and should be visible in the southeast around 11:00 p.m. Each week you will find Jupiter rising roughly30 minutes earlier than it did in the previous week. Opposition for Jupiter occurs on July14. On this date Jupiter will be at its brightest for the 2020 apparition.  After this date Jupiter will rise before the Sun sets.

Saturn

Saturn is rising around 10:25 p.m. and will be visible in the southeast around 11:20 a.m. Saturn reaches opposition on July 20. For those with a telescope keep track of the orientation of Saturn’s rings.  Since Saturn is tilted on its rotational axis, we cross the plane of Saturn’s ring every 13 to 15 years.  We are headed towards another ring plane crossing on March 23, 2025. Over the next five years you will notice Saturn’s rings will gradually incline towards an edge on appearance.

2020 Great Conjunction

This year the planets Jupiter and Saturn will reach conjunction.  A conjunction is when two or more celestial bodies share the same right ascension.  For Jupiter and Saturn this astronomical event occurs every 20 years. The conjunction occurs on December 21, 2020.  You will find the two planets close together in the southwest just after sunset on this date.

Visit the James S. McDonnell Planetarium for more information on what’s up!

Night Sky Update: June 19-June 27, 2020