This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, May 29, 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 5:39 a.m. on Friday, May 29 and sunset is at 8:18 p.m. providing us with 14.5 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 10:12 p.m. this week. For those with a sundial, solar transit or local noon occurs around 12:59 p.m. this week.

2020-05-29 5:39 a.m.8:18 p.m.
2020-05-30 5:39 a.m.8:19 p.m.
2020-05-31 5:39 a.m.8:20 p.m.
2020-06-01 5:38 a.m.8:20 p.m.
2020-06-02 5:38 a.m.8:21 p.m.
2020-06-035:38 a.m.8:22 p.m.
2020-06-04 5:37 a.m.8:22 p.m.
2020-06-05 5:37 a.m.8:23 p.m.
2020-06-06 5:37 a.m.8:23 p.m.

Moonrise for Friday, May 29 occurs at 12:10 p.m. and moonset will occur at 1:30 a.m. on the following day. On Friday, May 29 the Moon will reach first quarter at 10:30 p.m. Full moon occurs on June 5.

International Space Station (ISS) Observing

Credit: NASA

Visible passes of ISS from St. Louis for the week of May 29 occur during evening hours. The best of these occur on the evenings of May 30 and June 2 and 3. Use the table below for information about these and other visible passes of ISS.

History will hopefully occur over the weekend with the launch of the first Commercial Crew Program astronauts. This will be a return to launching astronauts from US soil and it will be the first ever crew launched into Earth orbit by a commercial company. The next scheduled launch will be Saturday, May 30 and if needed Sunday, May 31.  Weather permitting, if the launch occurs there will be viewing opportunities for the Dragon Capsule as it approaches ISS.  Information for these can be found at NASA TV will stream a live views of the launch.

Catch ISS from St. Louis starting Friday, May 29

Date Starts  Max. altitude  Ends  
29 May-1.5 21:36:0010NNW 21:38:3119NNE 21:41:0210ENE
29 May-1.9 23:12:1410NW 23:14:0229WNW 23:14:0229WNW
30 May-1.1 20:48:2910NNW 20:50:2815NNE 20:52:2710NE
30 May-3.7 22:24:2410NW 22:27:4668NE 22:27:5467ENE
31 May-2.8 21:36:4010NW 21:39:5240NNE 21:41:4920E
31 May-1.1 23:13:5310W 23:14:4414W 23:14:4414W
01 Jun-2.1 20:49:0110NNW 20:51:5526NNE 20:54:4910E
01 Jun-2.8 22:25:3810WNW 22:28:4136SW 22:28:4136SW
02 Jun-3.7 21:37:3710NW 21:40:5869SW 21:42:4026SE
03 Jun-3.6 20:49:4510NW 20:53:0766NE 20:56:2710ESE
04 Jun-1.8 21:39:0910W 21:41:4621SW 21:43:4413S
05 Jun-2.7 20:50:5210WNW 20:54:0137SW 20:57:0910SSE

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

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, 40 Minutes After Sunset, May 29, 2020
Credit: Stellarium, EG

Looking Southeast, 4:00 am, May 30, 2020
Credit: Stellarium, EG

This week, four naked eye planets are visible. Mercury will be visible in the west about 40 minutes after sunset. Mars, Jupiter and Saturn are visible in the south and southeast in the morning hours before sunrise.

Venus will reach inferior conjunction on June 3.  With this we say goodbye to the current Venus apparition. On May 29 Venus will be 7.9° from the Sun making it a little too close for comfort. My general rule of thumb is if an object is not 10° above the horizon, it is not likely to be seen except for those with exceptionally clear horizon views.  Most importantly, anything within 10° from the Sun is getting to close to the Sun in the sky. Venus will return to the morning skies just before sunrise by the end of June.

For those tracking Jupiter and Saturn as they approach their great conjunction later this year, the two gas giants currently appear just over 4° apart in the sky.  If you keep watching them as 2020 progresses, you will see some interesting behaviors that inspired early astronomers to watch the skies.


Mercury has started another evening apparition.  You can look for Mercury about 40 minutes after sunset in the west. Greatest elongation occurs on June 4.  As we lose Venus, we will see Mercury climb higher in the sky. Mercury will set around 10:07 p.m.


The red planet rises around 1:58 a.m. and will be high enough to see in the southeast by 3:00 a.m. Opposition for Mars occurs on October 13, 2020. As we head towards this date Mars will appear brighter and its surface will eventually be visible through a telescope.


The king of the planets is rising around 11:39 p.m. and should be visible in the southeast around 12:30 a.m. Each week you will find Jupiter rising about 20 minutes earlier than it did in the previous week.


Saturn is rising around 11:55 p.m. Like Jupiter you will need a clear sky to the southeast to catch the ring planet around 1:00 a.m. Later this year Jupiter and Saturn will reach conjunction on December 21, 2020. You can track these planets as they appear to chase one another throughout the rest of this year.

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 only occurs every 20 years. The conjunction will occur on December 21, 2020.  You will find the two planets close together in the southwestern sky just after sunset on this date.

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

Night Sky Update: May 29-June 6, 2020