This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, November 20, 2020.

Information updated weekly or as needed.

Times given as local St. Louis time which is Central Standard Time (CST). 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 now -6 Hours from UT.

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 Orion the Hunter November 20 at 10:00 pm
Credit: Stellarium, EG

The observing highlight for this week is the constellation Orion. This familiar constellation can be found in the east by 9:00 p.m. Look for the familiar X-shape with the three stars in the middle forming his belt. Orion is a great target for any level of observing experience. He is easy to find, will help you find several other constellations and he offers up numerous objects that are great for naked eye, binocular and telescope viewing.

For those that will be observing naked eye, there are several bright stars that are intriguing. The red supergiant star Betelgeuse is a great example of an evolved star that will likely end in a supernova. Looking at this star in the top left corner of Orion should reveal a reddish colored star. Most stars will appear white to our eyes because we are not great at seeing colors in low light conditions. All stars have color, but it is only the brightest that will reveal their hue to the unaided eye. Another colorful star in Orion is Rigel. This blue supergiant is the brightest star in Orion that will also provide interest through a telescope. Rigel is a member of a multiple star system that will make a nice target for telescopes larger than 4-inches.

Those with binoculars can enjoy several open star clusters and the star forming region Messier 42. Orion’s easiest star cluster to find is Collinder 70. To find this star cluster all you need to look for is Orion’s belt. The three bright stars in the belt are members of this cluster that contains over 100 stars. Due to the large amount of sky it covers, this target is best seen through binoculars. Looking south of the belt you will find a smaller line of stars that appear almost perpendicular to the belt. This area is best seen through a telescope but the emission nebulae Messier 42 will be easily seen through binoculars.

Through a telescope, M42 will be a diffuse object that may look like a trapezoid or handheld fan shape. What you see will depend on the telescope and viewing conditions. M42 is a large volume of dust and gas that is turning into stars. What lights up this nebula is a group of stars called the Trapezium. This young cluster represent some of the stars that have already formed from this nebula. Through a telescope four stars in a trapezoid shape are easily seen and through a large enough telescope several other members can be seen.

Orion is a target that can keep you busy for most of the night. I would always recommend spending time touring this famous constellation that is loaded with interesting targets. A star chart and time is all that you really need to get started.

The Sun and Moon


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

Sunrise is at 6:49 a.m. on Friday, November 20 and sunset is at 4:44 p.m. providing us with roughly 10 hours of daylight. Even after sunset, the light from the Sun will dimly illuminate our sky for about 1 hour and 30 minutes. This period is called twilight, which ends around 6:17 p.m. this week. For those with a sundial, local noon occurs around 11:47 p.m. this week.

DaySunriseSunset
2020-11-20 6:49 a.m.4:44 p.m.
2020-11-21 6:50 a.m.4:44 p.m.
2020-11-22 6:51 a.m.4:43 p.m.
2020-11-23 6:52 a.m.4:43 p.m.
2020-11-24 6:54 a.m.4:42 p.m.
2020-11-25 6:55 a.m.4:42 p.m.
2020-11-26 6:56 a.m.4:41 p.m.
2020-11-27 6:57 a.m.4:41 p.m.
2020-11-286:58 a.m.4:41 p.m.

Moon 

Moonrise for Friday, November 20 occurs at 12 16 p.m. and moonset will occur at 10:16 p.m. On Friday, November 20 the Moon will exhibit a waxing crescent phase with 37% of the lunar disk illuminated. First quarter moon occurs on November 21 at 10:45 p.m.

International Space Station (ISS) Observing

Credit: NASA

Visible passes of ISS from St. Louis for the week of November 20 occur during evening hours. The best passes this week occur on the evenings of November 21 and 22. Use the table below for information about these and other visible passes this week.

Catch ISS from St. Louis starting Friday, November 20

Date Starts  Max. altitude  Ends  
TimeAlt.Az.TimeAlt.Az.TimeAlt.Az.
20 Nov-2.5 17:15:1810SSW 17:18:1328SE 17:21:0910ENE
20 Nov-1.8 18:51:5510W 18:54:0927WNW 18:54:0927WNW
21 Nov-3.2 18:04:0710WSW 18:07:2350NW 18:08:4629NNE
22 Nov-3.8 17:16:3010SW 17:19:5287NW 17:23:1410NE
22 Nov-1.1 18:54:5210WNW 18:56:1715NW 18:56:1715NW
23 Nov-1.8 18:06:4110W 18:09:2222NNW 18:10:4517N
24 Nov-2.3 17:18:4110W 17:21:4431NNW 17:24:4710NE
25 Nov-1.3 18:09:5710NW 18:11:3513NNW 18:12:3212N
26 Nov-1.5 17:21:3610WNW 17:23:4916NNW 17:26:0210NNE

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 6:30 pm, November 20, 2020
Credit: Stellarium, EG


Looking East, 6:15 am, November 21, 2020
Credit: Stellarium, EG

This week, five naked eye planets are visible. Jupiter and Saturn are found in the southwest once it is dark. Mars is found high in the east after sunset. Mercury and Venus can be found in the eastern sky before sunrise.

For those tracking Jupiter and Saturn as they approach their great conjunction later this year, the two gas giants currently appear about 3.2° apart in the sky. From now until December 21, Jupiter will appear closer to Saturn each night.

Mercury

Mercury is headed towards superior conjunction on December 19. As the days go on, Mercury will be seen lower to the horizon each day which makes Mercury increasingly difficult to see. For many of us, Mercury is already lost to view due to buildings or trees in the southeast. However, for those with clear southeastern horizons you may still catch a peak of Mercury. At 6:15 a.m., you will find Mercury about 7.5° above the horizon. Keep in mind that civil twilight will begin around 6:20 a.m. so the sky will be bright. As we did last week first find Venus. If you imagine Venus as the center of a clock face, Mercury will be about 13° below Venus at the 7 o’clock position.

Venus

Venus rises at 4:21 a.m. and will be easily seen by 5:20 a.m. Venus remains a morning object until March 26, 2021 when it reaches superior conjunction. Since Venus has passed greatest western elongation, it is exhibiting a gibbous phase.

Mars

Currently Mars appears as a -1.5-magnitude object that will be visible in the east about 30 minutes after sunset. Mars sets by 3:16 a.m. We are still near enough to Mars that surface features are visible through telescopes. Earth is moving away from Mars which means Mars is getting fainter each night. The observing season for this apparition ends around March 10, 2021 and superior conjunction occurs on October 7, 2021.

Jupiter

Look for Jupiter in the south about 30 minutes after sunset. Jupiter will set at 8:28 p.m. Those with a telescope can enjoy views of Jupiter’s cloud features and the Great Red Spot when it is pointed towards Earth.

Saturn

Look for the ringed planet in the south about 30 minutes after sunset. Saturn sets at 8:45 p.m. 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.

Uranus

Uranus is not a planet we normally include in this section. Even at its dimmest, the giant planet does hover within naked eye visibility. That said, it is so close to the visible limit of the human eye it just is not reality for most of us to see Uranus without binoculars or a telescope. Uranus is just past opposition and as such, it is still easy to spot. You can find Uranus in the constellation Aries the Ram. The current magnitude for Uranus is 5.7. A finder chart for Uranus can be found here.

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: November 20-November 28, 2020