This is the Saint Louis Science Center’s NIGHT SKY UPDATE for the week of Friday, May 27, 2022.
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
Public telescope viewings at the McDonnell Planetarium have returned as part of the Saint Louis Science Center’s First Friday event. As we ease back into our telescope nights, they will operate a little different than before. To take part in our telescope viewings you will need to get a ticket for the planetarium show that starts at 7:00 p.m. as part of the First Friday event. Tickets for the First Friday planetarium show are free, but they can only be picked up at the Saint Louis Science Center on the night of the event. After the planetarium show ends you will be able to go outside and look through telescopes weather permitting. We will update this posting if anything changes.
Solar telescopes viewings have also returned and will take place every Sunday from 11:00 a.m. to 3:00 p.m. weather permitting. Solar Sundays will run from May 29, 2022, to September 4, 2022. The return of Solar Sundays is a good opportunity to prepare for the upcoming solar eclipses in 2023 and 2024.
Observing Highlight of the Week
HST image of Comet 73P/Schwassmann-Wachmann 3 Fragment B from 2006. Image credit: NASA, ESA, H. Weaver (APL/JHU), M. Mutchler and Z. Levay (STScI). Animation from three images by Vesta.
A possible meteor shower is set to occur at the end of May this year with a peak date of May30/31, 2022. The shower is known as the tau Herculids which may put on quite a show for us on Monday evening into Tuesday morning. This rather unknown meteor shower has surged into the awareness of the public recently thanks to a possible outburst of activity that has been predicted. These kinds of predictions often do not live up to expectations, so it is important to approach these events with that in mind. The tau Herculids could be amazing, or it could be a dud. What we see on May 30/31, 2022, is dependent on several variables.
To begin, we should start with what a meteor shower is. Often called shooting stars, meteor showers are caused as Earth moves through debris from comets or asteroids. The bright streaks of light seen as a meteor appears is caused by debris from space smashing into Earth’s atmosphere. As this happens, the air in front of the meteor is compressed causing it to heat up. In turn the air heats up the meteors vaporizing them causing a bright streak of light. If the orbit of a comet or asteroid is close enough to Earth, their debris streams can intersect Earth’s orbit leading to a meteor shower.
Meteor showers are identified by their radiant. A radiant is the point in the sky that meteors appear to emanate from. This does not mean what you see starts at the radiant but rather if you note the direction traveled by a meteor, that path will trace back to the radiant. A radiant occurs because the Earth is moving through debris in space. Something similar occurs when you drive into snow. The snow you see striking your windshield appears to come from one spot in front of you.
The comet that is connected to the tau Herculid meteor shower is called 73P/Schwassmann-Wachmann 3 (SW3). This comet was discovered in 1930 by German astronomers Arnold Schwassmann and Arno Arthur Wachmann. The year it was discovered, it was projected to cause a meteor shower with the radiant located near the star tau Herculis. No meteor shower was observed and comet SW3 was eventually lost. SW3 orbits the Sun every 5.4 years and is near Earth every 16 years. Eventually, it was found again during an apparition in 1979. SW3 is a faint comet and as such, it is difficult to find. This changed in 1995 as the comet underwent a dramatic brightening to naked eye visibility.
The cause of the dramatic brightening was SW3 began to fragment. Comets are fragile and porous icy remnants left over from the formation of our solar system. As SW3 began to break apart, it ejected dust and other large particles into space. SW3 broke into several large fragments which have also started to fracture. Gravitational forces encountered by the comet will eventually tear it apart. The dramatic increase in visual magnitude of SW3 after the comet broke apart in 1995 suggested there was a massive expulsion of dust.
A few studies of the material ejected from the comet suggests that Earth might pass through this debris at the end of May 2022. Whether or not this happens is dependent on the velocity of the debris ejected. If it was high enough to overcome the pressure caused by solar radiation, it is possible Earth could encounter the debris. If this is the case, we might see a meteor shower with visibility rates comparable to showers like the Geminids in December. Others have also noted it is possible we could see a major outburst of meteors or what is known as a meteor storm. As exciting as this might be, we must remember that one of the studies did not favor Earth encountering the debris from the 1995 breakup event. It is entirely possible we won’t see any meteors.
If the tau Herculids puts on a show, there are a few things to be aware of. First, the peak of the tau Herculids is expected to occur sometime around 0500 UT On May 31, 2022. This converts to roughly midnight in St. Louis. The time is an estimate, so it is encouraged to start observing before the expected peak. The peak activity is expected to last a few hours. Secondly, the radiant for the tau Herculids is no longer in Hercules, but instead is expected to be in the constellation Boötes, northwest of the bright star Arcturus. Bootes will be found overhead at midnight. The bright orange star seen overhead at this time is the star Arcturus. I have seen several different positions for the tau Herculids radiant, but if you can find Arcturus in the sky, you will be looking in the right direction.
Keep in mind that meteors will appear to emanate from the radiant in all directions, but they will not always be seen right by it. You will want to find a view that offers as clear a view of the horizon in all directions. You will also want a chair that reclines as much as possible. I like using what many call Zero-G chairs, which recline to a horizontal position. If you do not have one of these chairs you can just lie on the ground.
The weather forecast currently shows decent weather for the night of May 30/31, 2022. As we all know conditions can change at anytime so keep an eye on the forecast as we approach Monday evening. The clear sky chart is an ideal forecast to watch. You can find the St. Louis Clear Sky Chart here. Also remember that the farther you are from city lights, the better your chance of seeing meteors. The tau Herculids are expected to enter Earth’s atmosphere are lower velocities compared to other meteor showers. This means they will likely be faint. Moon light will not be an issue but city light will.
If you are interested in a more detailed look into Comet 73P/Schwassmann-Wachmann 3 and the potential tau Herculid meteor shower, check out the links below. I hope the tau Herculids will prove to be a great meteor shower, but we will have to wait and see. If you would like to learn more about meteor showers, I would visit both the American Meteors Society (AMS) and the International Meteor Organization (IMO) websites. Each year the IMO publishes a meteor shower calendar highlighting meteor shower activity, including anything that is out of the norm. Reading this each year is a way to determine which showers will be ideal for your location.
Will Comet 73P/Schwassman-Wachmann 3 produce a meteor outburst
https://skyandtelescope.org/astronomy-news/update-on-a-possible-outburst-of-meteors/
https://blogs.nasa.gov/Watch_the_Skies/tag/tau-herculids/
The Sun and Moon
The Moon as seen from the International Space Station, on July 31, 2011.
Credit: NASA
Sunrise is at 5:40 a.m. on Friday, May 27 and sunset is at 8:16 p.m. providing us with roughly 14.5 hours of daylight. Even after sunset, the light from the Sun will dimly illuminate our sky for roughly 1 hour and 50 minutes. This period is called twilight, which ends around 10:09 p.m. this week. For those with a sundial, local noon occurs around 12:57 p.m. this week.
| Day | Sunrise | Sunset |
|---|---|---|
| 2022-05-27 | 5:40 a.m. | 8:16 p.m. |
| 2022-05-28 | 5:40 a.m. | 8:17 p.m. |
| 2022-05-29 | 5:39 a.m. | 8:17 p.m. |
| 2022-05-30 | 5:39 a.m. | 8:18 p.m. |
| 2022-05-31 | 5:38 a.m. | 8:19 p.m. |
| 2022-06-01 | 5:38 a.m. | 8:19 p.m. |
| 2022-06-02 | 5:38 a.m. | 8:20 p.m. |
| 2022-06-03 | 5:37 a.m. | 8:21 p.m. |
| 2022-06-04 | 5:37 a.m. | 8:21 p.m. |
Moon
Moonrise for Friday, May 27 occurred at 4:09 a.m. and moonset will occur at 5:48 p.m. On Friday, May 27, the Moon will exhibit a waning crescent phase with 7% of the lunar disk illuminated. New moon occurs on May 30, 2022, at 6:30 a.m.
International Space Station (ISS) Observing
Visible passes of ISS from St. Louis for the week of May 27 occur during evening hours. The best passes occur on the evening of May 30 and June 2. Use the table below for information about these and other visible passes this week.
Catch ISS from St. Louis starting Friday, May 27
| Date | Starts | Max. altitude | Ends | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Time | Alt. | Az. | Time | Alt. | Az. | Time | Alt. | Az. | ||
| 28 May | -2.3 | 21:48:30 | 10 | NW | 21:51:32 | 31 | NNE | 21:53:07 | 20 | ENE |
| 28 May | -1 | 23:25:20 | 10 | WNW | 23:26:01 | 14 | W | 23:26:01 | 14 | W |
| 29 May | -1.7 | 21:00:35 | 10 | NNW | 21:03:15 | 21 | NNE | 21:05:54 | 10 | ENE |
| 29 May | -3 | 22:36:56 | 10 | WNW | 22:39:38 | 45 | W | 22:39:38 | 45 | W |
| 30 May | -3.8 | 21:48:42 | 10 | NW | 21:52:04 | 84 | NE | 21:53:16 | 37 | SE |
| 31 May | -3.1 | 21:00:35 | 10 | NW | 21:03:51 | 47 | NE | 21:06:56 | 11 | ESE |
| 31 May | -1.5 | 22:38:05 | 10 | W | 22:39:50 | 16 | WSW | 22:39:50 | 16 | WSW |
| 01 Jun | -2.4 | 21:49:18 | 10 | WNW | 21:52:16 | 30 | SW | 21:53:33 | 22 | S |
| 02 Jun | -3.3 | 21:00:50 | 10 | WNW | 21:04:08 | 56 | SW | 21:07:18 | 11 | SE |
| 04 Jun | -1.5 | 21:01:45 | 10 | W | 21:04:07 | 18 | SW | 21:06:27 | 10 | 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 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 southeast at 4:45 a.m. May 29, 2022. Credit: Stellarium, EG
This week, four naked eye planets are visible. Venus, Mars, Jupiter and Saturn are seen in the east and southeast before sunrise.
Venus
Venus has started a morning apparition and will be seen in the southeast before sunrise. Venus rises at 3:59 a.m. and should be easy to spot in the southeast by 5:00 a.m. The current morning apparition lasts until the third week of October 2022. Venus reaches superior conjunction on October 22, 2022.
Mars
A new apparition for Mars has begun. Mars rises at 2:51 a.m. Start looking for Mars around 4:00a.m. as it clears trees and buildings. Mars will continue to climb out of the Sun’s glare as it heads towards opposition later this year on December 7, 2022.
Jupiter
Jupiter rises at 2:50 a.m. and should be visible by 4:00 a.m. As the year goes on, Jupiter will rise about 20 minutes earlier than it did the week before. Jupiter will reach opposition on September 26, 2022, so our best views of this giant world will come at the end of summer and through the fall months.
Saturn
Saturn rises at 1:15 a.m. Start looking for Saturn around 2:15 a.m. in the southeastern sky. Saturn will reach opposition on August 14, 2022. As we head to this date, Saturn will rise earlier each day.
James S. McDonnell Planetarium
Night Sky Update: May 27 – June 4, 2022