What’s Up in the Night Sky? May 2021

Fred Barrett | Apr 28, 2021

Just about every month I give you a reminder about what meteor shower or showers to watch out for. I also point out that meteors result when Earth plows through dust and particle trails left behind by comets. That started me thinking about, well, dust! There’s dust everywhere in the Universe. Besides comets, where does it all come from? Here’s what I found out while rummaging on the internet.

None of the dust in space resembles the dust we have on Earth. Outside our houses we have small bits of soil and rock while inside, we track in dirt when we come through the door. We also find animal and human skin particles and pet hairs and insect parts. Outer space dust just isn’t the same. There aren’t many dogs and cats living in outer space!

When we leave Earth we find dust within our solar system and other stellar systems – interplanetary dust. There’s dust between the stars within our galaxy and other galaxies – interstellar dust. We can directly see the dark band of dust through our Milky Way galaxy when it lifts up high in our sky at midsummer. There’s also cosmic dust between the galaxies of the Universe – intergalactic dust. Different types of stars form 2 elements that comprise interstellar and intergalactic dust.

Silica dust is produced in the atmospheres of cool red giant stars that also have a lot of oxygen. Carbon dust is also is made in similar red giant stars with one difference. Their atmospheres are rich in carbon. Another type of interstellar and intergalactic dust is not formed by stars. This is a graphite dust which is only produced by supernovae.

Interplanetary dust contains some of the dust that floats between stars and galaxies but includes particles produced by asteroid and larger body collisions. Comets only contribute a relatively small amount of dust. Most of it is frozen at the icy heart of the comet and is only released when the comet passes close to a star or, in our system, close to the Sun. The dust released along the comet’s orbit provides the spectacular light show that we call a meteor shower.

Speaking of meteor showers, early May has the Eta Aquarid meteor shower. It’s active until about May 28th and peaks late on the night of May 5th. The best viewing is in the early hours of the 6th when the radiant is rising in Aquarius and the Moon is out of the picture. The meteors are the dust and debris from Halley’s Comet cast off by its countless passes around the Sun. Halley is currently far off in its orbit around the Sun but on May 6th Earth will be bullying its way through this debris trail. An hourly rate of 40 is possible through the night. I’ll remind you again that meteors can appear in all parts of the sky and it’s not necessary for the radiant to be prominent above the horizon.

There is a total eclipse of the Moon on the 26th. Sadly, in our eastern part of the country, it starts about 5 am when the sky is getting light and totality will occur a little after the 7 am when our Sun will wash out any decent viewing.

You should follow Mercury, Venus and Mars this month. Basically they are above the horizon in the west just after sunset. Mercury and Venus are in Taurus and Mars is above them in Gemini. They set quickly early in the month. As the month moves on they are higher at sunset and last longer. It gets better as the month progresses. Mercury and Venus are stunningly close on the 28th about a half hour after sunset. Watch for them. Mars is pretty small now but still worth finding in binoculars. Get out there and challenge yourself.

Jupiter and Saturn are in the southeast. Saturn rises about 2:30 am in early May and 1 am late in the month. It can be found in Capricorn and rises higher as the night progresses. A modest telescope will let you follow its moons from night to night – especially the largest, Titan. Jupiter comes up about 50 minutes after Saturn and sits in Aquarius where it will linger for most of 2021. Its moons are endlessly fascinating and easy to view and follow. Uranus is in the northeast of Aquarius and Neptune is in Aries. You will have to do a little research to search them out.

Highlights: May 3 - Last quarter Moon, May 5 - Eta Aquariid meteor shower peaks, May 11 - New Moon. The Moon is at apogee – 404,152 Kms. May 16 - The Moon is 1.5 degrees north of Mars 1 am EDT. May 19 - First quarter Moon. May 25 - The Moon is at perigee – 355,237 Kms. May 26 - Full Moon. This Moon is named the Full Flower Moon. My Daffodils had a good run; there may be more in the shaded spots. Crocuses were a fine show. They don’t last long. Lots of tulips are ready to burst open. It is also known as the Full Corn Moon. Haven’t planted my corn yet but then, it snowed yesterday. May 28 - Mercury and Venus are extremely close about a half hour after sunset.

These are times of isolation and distancing but amateur astronomy can be a shared activity that provides plenty of fresh air, awe and delight. Observing at a safe talking distance from others doesn’t diminish the enjoyment. A caution: be careful about sharing equipment without careful cleaning between users.

Stay safe, stay separate and enjoy the sky. That’s a wrap. Keep looking up!

“The Beginner’s Observing Guide by Leo Enright is an invaluable companion for adventures in the sky. It also contains useful star charts. It can be ordered from the Royal Astronomical Society of Canada at www.rasc.ca/publications. A subscription to our very own excellent Canadian astronomy magazine “SkyNews” can be arranged at the RASC website as well.

Let me know how your observing has gone this month, especially anything unusual. I enjoy the feedback. If you have any questions or suggestions you can contact me through this paper or email me at This email address is being protected from spambots. You need JavaScript enabled to view it. . Clear Skies! Fred