The Night Sky This Month: April 2021

Messier 106
Image credit: KPNO/NOIRLab/NSF/AURA

While many images of M106, which is a perennial favorite of amateur astronomers the world over, taken with the Hubble Space Telescope exist, no Hubble image shows a complete view of the galaxy. By way of contrast, the image above was recently obtained by the 4-metre Nicholas U.

Mayall Telescope at Kitt Peak National Observatory, shows not only the entire galaxy, but also its two closest satellites: dwarf galaxy NGC 4248 to the lower right, and dwarf galaxy UGC 7358 to the lower left. The bright, fuzzy stars in the foreground are stars in the Milky Way Galaxy and are therefore unrelated to M106 in the constellation Canes Venatici.

The most noteworthy aspect of this view is the warped inner disc of the spiral galaxy. The core of this spiral galaxy contains an unusually energetic 40-million solar mass black hole that is churning up the material in its immediate surroundings, thus distorting the inner disc and creating the enormous streamers of pink-glowing material in the galaxy’s inner regions.

The Moon Phases in April 2021

Last Quarter New Moon First Quarter Full Moon
April 4th April 11th March 20th April 26th

The Full Moon of the 26th will be the first of three Super Moons to occur during 2021. The second Super Moon will occur on May 26th, while the third Super Moon will occur on June 24th.

The Planets in April 2021

The month of April does not offer much in the way of planetary viewing in the northern hemisphere, but below are some details of what to expect, nevertheless.

Mercury will reach a point of superior conjunction with the Sun on the 19th of April, and is therefore too close to the Sun to be visible.

Venus was at a point of superior conjunction with the Sun on the 26th of March and is too close to the Sun to be visible.

Mars is now an early evening object, rising as it does at about 20:54 (BST) as seen from London, from where it will be about 38 degrees above the western horizon. Note though that Mars will set at about 01:27 (BST).

Jupiter was at a point of conjunction with the Sun on the 19th of January, and although the ‘King of the Planets’ becomes visible about 90 minutes or so before dawn for much of April, it will not rise higher than 9 degrees or so above the south-eastern horizon. Note that since dawn occurs at about 05:42 (BST), it might be impossible to get clear views of the planet.

Saturn was at a point of conjunction with the Sun on the 124th of January, and as a result, the planet will not be visible from mid-northern latitudes because it will rise above the horizon during daylight hours.

Meteor Showers in April 2021

The Lyrids Meteor Shower, which originates from debris shed by the comet C/1861 G1 Thatcher, is expected to peak after midnight on the night of the 22nd-23rd of April. Although the Lyrids typically runs from about the 16th of the month to around the 25th, it is not a particularly productive shower, and it seldom delivers more than about 20 or so meteors per hour during its peak.

However, while the Lyrids shower often produces slow, but bright meteor trails that can sometimes persist for several seconds, the Moon will be nearly full during the peak, meaning that only the brightest meteors may be visible. While the showers’ radiant is in the constellation Lyra, meteors can appear from almost any point in the sky.

Deep Sky Objects to Look For in April 2021

Prominent constellations at this time of the year include Canis Major, Canis Minor, Auriga, Orion, Gemini, Taurus, Cancer, and the north circumpolar constellation Ursa Major. Weather and seeing conditions permitting, these constellations host a wide range of deep-sky objects that can be observed with modest amateur astronomy equipment. Below are some details of a few such objects-

Thor’s Helmet Nebula (NGC 2359)

Thor’s Helmet Nebula
Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona

Located about 15,000 light-years away in the constellation Canis Major, this nebula bears some resemblance to an ancient Norse warrior’s helmet, hence its popular name. Although this nebula is not the biggest known planetary nebula, it does stretch across 30 light-years, which places it among the biggest planetary nebulae known to exist.

The central star in this nebula is a giant, super hot Wolf-Rayet star that is expected to explode in a supernova event in the (astronomical) near future.

Messier 67 (M67, NGC 2682)

Messier 67
Image credit: Sloan Digital Sky Survey

Located between about 2,600 light-years and about 2,900 light-years away in the constellation Cancer, this pretty cluster is famous for two things. The first is its remarkable (estimated) age of between 3.2 billion and 5 billion years, making it one of the oldest known open clusters. The second thing is the fact that it contains roughly 100 stars that closely resemble our Sun in terms of chemical composition.

Moreover, the cluster also contains about 30 blue stragglers, which are stars that likely merged, resulting in stars that are hotter, bigger, and more massive than their ages would allow. Overall, though, the variety of stars in this cluster makes it one of the most studied open clusters by investigators that are interested in stellar evolution.

The 37 Cluster (NGC 2169)

The 37 Cluster
Image credit: ScottRak

Located about 3,600 light-years away in the constellation Orion, this tiny cluster that stretches across a distance of just under 7 minutes of arc, contains only about 30 stars that are all estimated to be about 8 million years old. While this little cluster does not hold any particular scientific interest, the collection of bright stars that comprise its core somewhat resembles the number 37, hence its name- The 37 Cluster.

Related Articles