Meteors, a Supernova in Virgo, an Evening Moon Meets Star Clusters, and Pre-dawn Planets on Parade!

This terrific image by Benjamin Law of Stouffville, Ontario shows the Leo Quartet of galaxies, which is located in the neck of Leo, the Lion. Leo is visible high in the western sky in evening during May. Other names for this group are Hickson 44 and the NGC 3190 Group. The north-up image covers 20 arc-minutes of sky left-to-right. (The moon’s diameter is 30 arc-minutes.) Benjamin’s images can be enjoyed at his Astrobin page at https://www.astrobin.com/users/Benjaminlaw/

Welcome to May, Stargazers!

Here are your Astronomy Skylights for the week of May 1st, 2022 by Chris Vaughan. Feel free to pass this along to your friends and send me your comments, questions, and suggested topics. You can also follow me on Twitter as @astrogeoguy! Unless otherwise noted, all times are expressed in Eastern Time. To subscribe to these emails please click this MailChimp link.

If you’d like me to bring my Digital Starlab portable inflatable planetarium to your school or other daytime or evening event, or deliver a session online, contact me through AstroGeo.ca, and we’ll tour the Universe, or the Earth’s interior, together! My terrific new book with John A. Read entitled 110 Things to See With a Telescope is a guide to viewing the deep sky objects in the Messier List – for both beginners and seasoned astronomers. DM me to order a signed copy!

This week has everything! Mercury near both the Pleiades and a comet after sunset, a supernova in a galaxy beside Messier 60 in Virgo, some meteors, a cross-quarter day, and a waxing moon that visits many star clusters in evening. The eastern morning sky will host five planets! Read on for your Skylights!

May Day

Thursday morning, May 5 is May Day! That date is one of the four so-called astronomical cross-quarter days, which are the midpoints between the solstices and equinoxes. May 5 falls exactly midway between the vernal equinox and the summer solstice – so we can expect the weather to start being less spring-like and more summer-like soon.

You can’t merely divide our 365.25-day year into four 91.3-day-long seasons and then count half that many days to reach the cross-quarters. Planets with elliptical orbits move faster when they are closer to the sun and slower when they are farther away. Since Earth is moving slower at aphelion in July, summers in the Northern Hemisphere are about five days longer than winters, which are a couple of days shorter than the average season-length.

May Day celebrations focus on romantic love, fertility in nature, and the arrival of spring flowers. In contemporary paganism, the day is called Beltane. An old Irish tradition for it involved “Lucky Fire” leaping! In roman times the Maiouma festival honoured Dionysus and Aphrodite.

The other three cross-quarter days are Groundhog Day (Imbolc) on February 2, Lughnasath or Lammas on August 1, and Samhain on November 1. I think you can guess which spooky “holiday” that last one connects to. In most of those cases, the “holiday” is observed several days before the astronomical cross-quarter. For residents of the Southern Hemisphere, where the seasons are swapped from the Northern Hemisphere, the festivals are offset by six months.

Supernova Alert

On April 16, 2022, Japanese astronomer Koichi Itagaki discovered a brand new type Ia supernova that had exploded in the spiral galaxy NGC 4647. That galaxy is 80 million light-years away from our solar system. It’s tucked in close to a big elliptical galaxy known as Messier 60 in the constellation of Virgo (the Maiden). This supernova occurred when a white dwarf star that had been absorbing mass off a closely orbiting companion star exceeded its “critical mass limit”, otherwise known as the Chandrasekhar Mass. Within seconds, the white dwarf star began runaway nuclear fusion, releasing as much light as the entire galaxy of stars that hosted it.

Type Ia supernovas emit a consistent amount of light at their peak. By comparing how bright they appear to the theoretical brightness, astronomers can estimate how far away they are; making them a Standard Candle for measuring distances in the Universe. After the peak, the supernova will gradually fade again over days and weeks.

I was able to see the supernova easily in my 12” reflector telescope in rural Ontario on Friday night. It appeared as a bright speck nestled between the fuzzy patches of Messier 60 and NGC 4647. If you have clear skies and a telescope of aperture 8” or greater, give it a try over the next few nights. Messier 60 is located on the eastern side of the Virgo Cluster of Galaxies, about 25% of the way from the bright star Vindemiatrix to the bright star Denebola. You can find a gallery of photos at https://www.rochesterastronomy.org/sn2022/sn2022hrs.html

Eta-Aquariids Meteor Shower

The annual Eta-Aquariids Meteor Shower is produced when Earth travels through a cloud of particles of material left behind by repeated passages of Halley’s Comet. Those particles drop through our atmosphere at high speeds, producing the long streaks of ionized gas and minerals we see as “shooting stars”. While we pass through the debris from May 3 to 11 annually, Earth will travel through the densest part of the cloud from Thursday night to Friday morning this week.  

On the peak night, watch for up to a few dozen meteors per hour, including some fireballs. True Aquariids meteors will appear to be travelling away from a radiant point in the sky near the constellation of Aquarius (the Water-Bearer). That spot will lie near the southeastern horizon, above Mars and Saturn. The southerly radiant makes this shower better for observers at low latitudes. The 25%-illuminated crescent moon that sets around midnight won’t reduce the number of visible meteors too much.

To increase your chances of seeing meteors during any shower, find a dark location with lots of sky, preferably away from light polluted skies, and just look up with your unaided eyes. Binoculars and telescopes are not useful for meteors because their fields of view are too narrow to catch the streaks of meteor light. Don’t watch the radiant. Any meteors near there will have very short trails because they are travelling towards you. Try not to look at your phone’s bright screen – it’ll ruin your night vision. And keep your eyes heavenward, even while you are chatting with companions. Good luck!

The Moon Meets Star Clusters

The moon will return to visibility in the evening sky this week. Tonight (Sunday) you can try to spot its extremely thin crescent shining just above the west-northwestern horizon after sunset, with the dot of Mercury shining less than a fist’s width above it.

On Monday evening, the moon will have waxed a little fuller and climbed far enough above the sun to be seen easily. This time it will shine several degrees to the upper left (or 4° to the celestial east of) Mercury, allowing them to share the view in binoculars, starting a little before 8:30 pm local time. The bright star Aldebaran will shine a similar distance to the moon’s left. That orange star serves as the baleful eye of Taurus, the Bull. To the right of Aldebaran, look for the large, triangular grouping of stars that form the rest of the bull’s face. Those are the Hyades Star Cluster, or Melotte 41, named by British astronomer Philibert Jacques Melotte (1880 – 1961), who published a catalogue of star clusters in 1915. Swedish astronomer Per Collinder published his own list of clusters in 1931, giving the Hyades the additional designation of Collinder 50.

To the lower left of Mercury, you’ll find the Pleiades Star Cluster. It’s smaller, but brighter. Also known as the Seven Sisters, or Daughters of Atlas in Greek mythology, Subaru, meaning “Unite”, in Japan, and as Dilyehe “Pinlike Sparkles” in Navaho. The Anishnaabe of the Great Lakes region call it Bugonagiizhig, “The Hole in the Sky”, from whence human spirits arrived on Earth and later cross into the afterlife. The Maori call it Matariki. Astronomers use Melotte 22, Collinder 42, and Messier 45. Star clusters aren’t just random bunches of stars in the sky. They are stellar siblings that are traveling through our Milky Way galaxy together after being formed from the same molecular hydrogen gas cloud long ago. Clusters can disperse over time, and even eject members. Astronomers can tie those back to their “families” by using their common spectral characteristics, age, and proper motion.

The upright slope of the evening ecliptic will rotate the moon’s lit crescent toward the horizon – creating a Cheshire Cat’s smile effect. That whimsical shape will continue for several evenings beyond Monday. But by then, the moon will be setting later each night in a dark sky, and the “smile” will be widening.

Monday onward will also be a fine period to watch for Earthshine or the “Ashen Glow”, which is caused when sunlight reflected from Earth’s clouds and the shiny Pacific Ocean slightly illuminates and brightens the part of the moon that isn’t receiving direct sunlight. Some call this phenomenon “the old moon in the new moon’s arms”.

The moon will continue to travel upward (celestial eastward) through Taurus. On Tuesday night, look for a smaller star cluster named NGC 1746, Melotte 28, and Collinder 57 sitting just a thumb’s width below (celestial southwest of) the crescent moon, especially around 10 pm local time, when the sky will be darker.

On Wednesday night, the moon will cross Taurus’ boundary with Gemini (the Twins). That evening, the waxing crescent will shine several finger widths to the right (or 3 degrees to the celestial northwest) of the large open star cluster in Gemini (the Twins) known as Messier 35 (or the Shoe-Buckle Cluster, Melotte 41, Collinder 82, and NGC 2168). For observers located west of the Eastern Time Zone, the moon will appear a little closer to the cluster. The moon and Messier 35 will share the view in binoculars. To better see the cluster, which is almost as wide as the moon, hide the moon just beyond the right side of your binoculars field of view. Two medium-bright stars named Tejat Posterior and Tejat Prior (Mu and Nu Geminorum, respectively) form Castor’s toes. They can help you find the cluster even when the moon has moved away.

On Friday night, the moon will shine just to the lower left (celestial south) of Pollux, the brighter of the twin stars of Gemini. Whiter Castor will sparkle to their right. On Saturday night, the waxing gibbous moon will slide past the huge open star cluster in Cancer (the Crab) known as the Beehive, Praesepe, Messier 44, Melotte 88, and Collinder 189. After dusk, you’ll find the moon shining several finger widths to the upper right (or 3.5 degrees to the celestial north of) the cluster. Towards midnight, the continuous orbital motion of the moon will carry it a little closer to the Beehive. The moon and the cluster will be close enough to share the field of binoculars, but you’ll see more of the “bees” if you hide the moon just outside of your field of view.

The moon will end this week in eastern Leo (the Lion) on Sunday night, officially reaching its first quarter phase at 8:21 pm EDT (or 00:21 Greenwich Mean Time on May 9). Evenings this week will be ideal for viewing the spectacular lunar terrain while it is enhanced by the slanted rays of sunlight. Sites along the curved terminator, the pole-to-pole boundary that demarks the lit and dark hemispheres, are experiencing sunrise on the moon. The topography laying to the right (lunar east) of that boundary will be a dramatic combination of brightly lit peaks and crater rims with pitch dark shadows to their west. Grab your binoculars and telescopes! New zones will be enhanced each night.

The Planets

For observers located at mid-Northern latitudes, this week will offer several more excellent opportunities to see the elusive planet Mercury – a bucket-list item for many. Tonight (Sunday) look for Mercury’s bright dot shining about a fist’s diameter (10 degrees) above the west-northwestern horizon as the sky begins to darken after 9 pm local time. The planet will drop a little lower on each subsequent night this week. While this is the best evening showing for 2022 for us, it will be the year’s worst appearance of Mercury for observers in the Southern Hemisphere. Viewed in a telescope this week, Mercury will show a waning crescent shape. Always ensure that the sun has completely set before aiming binoculars or a backyard telescope towards the western horizon.

Once you’ve spotted Mercury, look to its lower right (celestial northwest) with binoculars to find the bright Pleiades star cluster in Taurus (the Bull). In a dark sky, the Pleiades sparkles with many stars. But in twilight, only the brightest 8 stars appear, shaped very much like a shortened Big Dipper. The Pleiades and the surrounding stars of Taurus will be dropping lower each night as they are carried to the celestial west by Earth’s motion around the sun. Mercury will be moving west, too – but more slowly – so it will move more and more above than the Pleiades each night. They’ll share the view in binoculars all week. See if you can see Mercury’s crescent in them! Don’t forget that the pretty crescent moon will join their party on Monday night.

The rest of the bright planets continue to shine in the eastern sky before sunrise. This morning, the faster eastward motion of very bright Venus carried it closely below less-bright Jupiter in a lovely conjunction that is very low in the eastern sky. For the rest of this week, Venus will rapidly slide to the left (celestial east) from Jupiter. They’ll still be close enough to see together in the eyepiece of a backyard telescope on Monday morning, where six times brighter Venus will exhibit a 68%-illuminated disk, and Jupiter will be flanked on the west by its four Galilean moons. Venus and Jupiter will share the field of view of binoculars until Friday. Both bright planets will be quite easy to see with unaided eyes between about 5 am local time and sunrise.

Plan to head outside earlier if you would like to see three more, fainter planets shining in a dark sky, surrounded by the stars of Capricornus (the Sea-Goat) and Aquarius (the Water-Bearer). Yellow-tinted Saturn will start the parade when it rises after 3 am local time. Reddish Mars, positioned about two fist diameters to Saturn’s left (celestial east), will follow about 45 minutes later. Distant blue Neptune, positioned about a fist’s width to Mars’ lower left, will not be easy to see unless you live near the tropics, where the ecliptic is more upright. The much brighter duo of Venus and Jupiter will gleam about 1.5 fist widths to Mars’ lower left. Venus’ dance past Jupiter will make our hot sister planet the last one to rise each morning, and it will also elongate their line from 3.5 fist diameters on Monday to 4.2 fists next Sunday morning. The line of planets is showing you the plane of our solar system.

Venus will exhibit a football-shape in a backyard telescope. Good binoculars can reveal that, too. Any size of telescope will show you Saturn’s full globe, its rings, and perhaps a few of its moons. Mars will exhibit a tiny, 90%-illuminated disk. Jupiter will also get a little higher and farther from the sun with each passing day, allowing you to enjoy its dark equatorial bands, Great Red Spot, and four Galilean moons. Turn all optics away from the east before sunrise, please!

Wondering about Uranus? That planet will reach conjunction with the sun on May Day! It will become visible in the pre-dawn sky after a meet up with Venus on June 11.

Comet Alert

A comet named C/2021 O3 (PanSTARRS) will be sharing the western post-sunset sky with Mercury this week. Tonight (Sunday), the comet will be sitting a palm’s width to Mercury’s right in Taurus; but the sky won’t be dark enough to see it. On each subsequent night this week, the comet will climb north through Perseus (the Hero), carrying it farther from the sun and allowing the sky to darken around it.

On Tuesday night, it will pass close to the right (or celestial west) of the medium-bright star Omicron Persei. On Thursday and Friday it will slide past the even brighter star Epsilon Persei. Keep trying and you might spot it as a faint greenish, fuzzy patch in good binoculars and backyard telescopes.

How we Describe (Classify) Galaxies and Tips for Galaxy Viewing

If you missed last week’s information about how we classify galaxies and some tips for finding and viewing them, it’s here.

Public Astro-Themed Events

Every Monday evening, York University’s Allan I. Carswell Observatory runs an online star party – broadcasting views from four telescopes/cameras, answering viewer questions, and taking requests! Details are here. They host in-person viewing on the first clear Wednesday night each month. Other Wednesdays they stream views online via the observatory YouTube channel. Details are here.

On Wednesday evening, May 4 at 7:30 pm EDT, the RASC Toronto Centre will live stream their monthly Recreational Astronomy Night Meeting at https://www.youtube.com/rasctoronto/live. Talks include The Sky This Month, how to encourage astronomy clubs in high schools, and equipment upgrades for Schmidt-Cassegrain Telescopes (SCTs). Details are here.

On Thursday, May 5 at 8 pm EST, the Department of Astronomy & Astrophysics at the University of Toronto will stream their AstroTour. The live, free event will feature PhD Candidate Fergus Horrobin discussing The Birth of Planetary Systems: From Star Formation to The Solar System. Details and the YouTube link are here.

Eastern GTA sky watchers are invited to join the RASC Toronto Centre and Durham Skies for solar observing and stargazing at the edge of Lake Ontario in Millennium Square in Pickering on Friday evening, May 6, from 6 pm to 11 pm. Details are here. Before heading out, check the RASCTC home page for a Go/No-Go call – in case it’s too cloudy to observe.

On Saturday, May 7, 2022 from 7 to 9 pm EDT, celebrate humanity’s return to the Moon and International Astronomy Day with the RASC’s Shooting for the Moon National Virtual Star Party on Zoom, including a pre-recorded talk and a live Q&A with Canadian Astronaut David Saint-Jacques from the Rio Tinto Alcan Planetarium in Montreal, live views of the Moon from across Canada, RASC Member’s moon content, and more! It will also be streamed on YouTube. Registration and details are here.

Public sessions at the David Dunlap Observatory may not be running at the moment, but RASC are pleased to offer some virtual experiences instead in partnership with Richmond Hill. The modest fee supports RASC’s education and public outreach efforts at DDO.

On Sunday afternoon, May 8 from 12:30 to 1 pm EDT, tune in for DDO Sunday Sungazing. Safely observe the sun with RASC, from the comfort of your home! During these family-friendly sessions, a DDO Astronomer will answer your questions about our closest star: the sun! Learn how the sun works and how it affects our home planet. Live-streamed views of the sun through small telescopes will be included, weather permitting. Only one registration per household is required. Deadline to register for this program is Wednesday, May 4, 2022 at 3 pm. Prior to the start of the program, registrants will be emailed the virtual program links. More information is here and the registration link is here.

My free, family-friendly Insider’s Guide to the Galaxy webcasts with Samantha Jewett of RASC National returns on Tuesday, May 10 at 3:30 pm EDT, when I’ll tell you how to take the free Stellarium program to the next level. Plus, we’ll continue with our Messier Objects observing certificate program and share some galaxy-viewing tips. You can find more details and the schedule of future sessions here.

Don’t forget to take advantage of the astronomy-themed YouTube videos posted by RASC Toronto Centre and RASC Canada.

Keep looking up, and enjoy the sky when you do. I love questions and requests. Send me some!