The Night Sky This Month: May 2021

NASA’s Ingenuity “helicopter”
Image credit: NASA/JPL-Caltech

This image above shows the shadow of NASA’s Ingenuity “helicopter”. The image was captured by an onboard, downward-facing camera as the craft hovered above the Martian surface during a test flight on April 19th 2021.

As this is the first time that a flying craft built on Earth had flown on a different world, NASA commemorated their achievement by honoring the memory of the Wright brothers for their achievement in building and flying the first successful heavier-than-air craft on Earth in 1903. In honor of the Wright brothers, NASA had tucked a small piece of the fabric that covered the first aircraft to complete a successful, albeit brief flight on Earth, under the Ingenuity’s solar panel.

There is perhaps no more fitting tribute to the Wright brothers and their efforts than taking a small part of the original Wright Flyer to Mars. More details on the piece of fabric can be found here.

The Moon Phases in May 2021

Third Quarter
New Moon
First Quarter
Full Moon
May 3rd May 11th May 19th May 26th

Note the Full Moon occurring on the 26th will be a Super Moon. On this occasion, the Moon will have an angular diameter of 31 minutes of arc, and will therefore be about 8% bigger than a “normal” Full Moon.

Also, during the Super Moon a brief total lunar eclipse will occur, which will be visible from New Zealand and eastern Australia, as well as from Japan, western North America, and much of the Pacific Ocean. The eclipse will be total from eastern Australia at about 11:19 (UT).

The Planets in May 2021

Mercury starts the month shining at magnitude -1, which is the brightest it has been this year. Now located just below the Pleiades Cluster, the little planet remains low on the horizon, but it will reach an elevation of about 11 degrees above the northwestern horizon on the 17th when it reaches its point of greatest eastern elongation with the Sun. On this date, the planet will shine at magnitude 0.14 and have an angular diameter of just more than 8 seconds of arc. Look for a close pairing with Venus just after sunset on the 28th of the month, when the two planets will be less than 0.5 degrees apart.

Venus starts the month shining at magnitude -3.88 and an angular diameter of about 10 seconds of arc. However, Venus will only rise to about 6 degrees above the horizon at the beginning of May. By month’s end, the planet will rise to about 11 degrees at sunset, and although Venus will remain an early evening object for the remainder of 2021, it will only reach its highest elevation during the first days of December. Until then, it might be difficult for observers north of mid-northern latitudes to spot the planet low on the horizon.

Mars begins May shining at magnitude +1.56 soon after sunset in the constellation Gemini, about 24 degrees above the western horizon. The Red Planet will remain visible for the next few months, but it is now approaching the Sun, and will therefore become increasingly difficult to spot from August to September until it becomes lost in the glare of the Sun in October.

Jupiter starts the month rising at about 2 hours before dawn, but since it will not rise above about 20 degrees above the horizon, it might be difficult to obtain clear views of the ‘King of the Planets’ through the thick atmosphere. Although Jupiter will rise about 3 hours before dawn by month’s end, it will remain at, or below 20 degrees above the horizon at dawn, meaning that it will be difficult to spot the planet throughout May.

Saturn starts the month rising about 30 minutes or so before Jupiter, and although it will shine at magnitude +0.71 and have an angular diameter of 39 seconds across its rings, it will remain below 20 degrees above the south-eastern horizon. Thus, as with Jupiter, it will remain difficult to obtain clear views of the planet through the murk of the atmosphere throughout May.

Meteor Showers in May 2021

The Eta Aquarids meteor shower, which is caused by debris left behind by the Comet Halley, usually runs from April 19th to about May 28th and is expected to peak on the night of May 6th/7th this year. Although this shower is considered prolific, with a maximum hourly rate of about 60 meteors, most activity is best seen from the Southern Hemisphere.

However, observers in the Northern Hemisphere can expect to see about 30 meteors per hour during the peak, which is expected to occur in the pre-dawn hours of the 7th of May, although the Second Quarter Moon may extinguish all but the brightest meteors as seen from urban areas. Note that while the shower’s radiant is in the constellation Aquarius, meteors from this shower could appear from almost any point in the sky.

Deep Sky Objects to Look For In May 2021

Prominent constellations at this time of the year include Gemini, Leo, Cancer, Virgo, and Ursa Major. With perhaps the exception of Gemini, these galaxies hold a rich variety of spectacular deep sky objects, with Leo being particularly rich in galaxies. While some galaxies in Leo are too dim to view with amateur equipment, it does contain two pairs of galaxies that are easy targets for small telescopes at low power. Below are some details, including details of yet another pair of easy-to-spot galaxies in Ursa Major-

Galaxies M65 and M66


This image shows the magnitude 9 galaxies M56 and M66 beneath Leo’s “belly”, almost at the same declination as the bright star Regulus. Finding the pair is, therefore, easy- simply locate Regulus, and sweep westward about nine degrees. At low power, both galaxies fit inside a single field of view.

Both galaxies are spirals, with M65 being a type Sa spiral, while M66, which is significantly bigger and more massive than M56, being a type Sb spiral, having a smaller nucleus and more loosely wound spiral arms.

Galaxies M95 and M96


This pair of spiral galaxies in Leo is a further seven degrees west of Regulus, almost at the midpoint between the stars Upsilon Leonis and Iota Leonis. M95 is a type SBb barred spiral located about 38 million light years away, while M96 is a type Sa spiral, located about 41 million light years away. Both galaxies can be seen in a single field of view in a small telescope at low power.

Both galaxies are members of the Leo I Group of galaxies, which has between 8 and 24 members, depending on the source consulted. Nonetheless, the Leo I Group is just one of many groups of galaxies in the Virgo Super Cluster, which comprises the combined Virgo Cluster and Local Group of galaxies. It is perhaps worth noting the Local Group of galaxies is an outlying member of the Virgo Cluster of galaxies.

Galaxies M81 and M82


Located n the upper right quadrant of the constellation Ursa Major, this pair of interacting galaxies can be viewed in a single field of view in a small telescope at low power. M82, also known as the Cigar galaxy due to its edge-on orientation, is shown on the right in this view.

The interaction with M81 has stirred up the material in M82, which is now undergoing an intense burst of star formation. As a result, M82 is now about five times as bright as the Milky Way, although M82’s core is at least 100 times as bright as the Milky Way’s core.

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