This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, March 27, 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.

Our next star party scheduled for Friday, April 3, 2020 has 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 this article will be updated once these events resume.

The Sun and Moon

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

Sunrise is at 6:53 a.m. on Friday, March 27 and sunset is at 7:20 p.m. providing us with about 12.5 hours of daylight.  Even after sunset, the light from the sun will still dimly illuminate our sky for about 1.5 hours.  This period is called twilight, which ends around 8:50 p.m. this week.  For those with a sundial, solar transit or local noon occurs around 1:06 p.m. this week.

Day Sunrise Sunset
 27 Mar 6:53 a.m. 7:20 p.m.
 28 Mar 6:51 a.m. 7:21 p.m.
 29 Mar 6:50 a.m. 7:22 p.m.
 30 Mar 6:48 a.m. 7:23 p.m.
 31 Mar 6:47 a.m. 7:24 p.m.
 01 Apr 6:45 a.m. 7:25 p.m.
 02 Apr 6:44 a.m. 7:26 p.m.
 03 Apr 6:42 a.m. 7:27 p.m.
 04 Apr 6:40 a.m. 7:28 p.m.


Moonrise for Friday, March 27 occurs at 8:45 a.m. and moonset will occur at 10:33 p.m.  On Friday, March 27 the moon will be exhibiting a waxing crescent phase with roughly 10% of the lunar disk illuminated. First quarter moon occurs on April 1.

International Space Station (ISS)

Credit: NASA

Visible passes of ISS from St. Louis for the week of March 27 occur during evening hours.  The best of these occur on the evenings of 19 and 20.  Use the table below for information about these and other visible passes of ISS.

Catch ISS from St. Louis starting Friday, March 27

 Date Mag Starts Max. altitude Ends
Time Alt. Az. Time Alt. Az. Time Alt. Az.
30 Mar -1.0 21:46:24 10 NNW 21:47:27 17 NNW 21:47:27 17 NNW
31 Mar -1.8 20:59:13 10 NNW 21:01:46 20 NNE 21:01:57 19 NNE
01 Apr -1.4 20:12:06 10 NNW 20:14:08 15 NNE 20:16:10 10 ENE
01 Apr -1.3 21:48:04 10 NW 21:49:27 22 NW 21:49:27 22 NW
02 Apr -3.1 21:00:44 10 NW 21:03:57 42 NNE 21:04:00 42 NE
03 Apr -2.4 20:13:27 10 NNW 20:16:24 27 NNE 20:18:36 14 E
03 Apr -1.2 21:50:10 10 WNW 21:51:35 21 W 21:51:35 21 W
04 Apr -3.6 21:02:32 10 WNW 21:05:51 62 SW 21:06:15 56 S


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, 7:50pm, March 27, 2020
Credit: Stellarium, WS

Looking Southeast, 6:15am, March 26, 2020
Credit: Stellarium, WS,

This week, all five naked eye planets are visible. Venus will be visible in the west just after sunset.  Mars, Jupiter and Saturn are visible in the southeast about 2 hours before sunrise. Mercury is only visible low in the morning twilight.


The brightest planet in the sky is visible as the sunsets.  It will be seen high in the west as the sun is setting. Venus reach maximum elongation for its current apparition, because of this Venus will set earlier each night as it heads towards inferior conjunction on June 3, 2020.


The red planet rises around 3:50 a.m. and will be high enough to see in the southeast by 4:30 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 3:38 a.m. and should be visible in the southeast a little after 4:00 a.m.


Saturn is rising around 4:01 a.m.  Like Jupiter you will need a clear sky to the southeast to catch the ring planet around 4:45 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!