The Night Sky This Month: June 2020

Mare Imbrium
Image credit: Ian Morrison

The summer solstice take place on June 20th this year, officially marking the start of summer in the northern hemisphere and the beginning of winter in the southern hemisphere.

This month, the Summer Triangle also appears overhead around midnight from mid-northern latitudes. Consisting of the brightest stars in Aquila, Lyra, and Cygnus, the Milky Way appears to run directly through this impressive asterism.

Read on discover more astronomical events and sights to look forward to in June.

The Moon in June 2020

The image above shows Mons Piton, a major stand-alone mountain in the eastern reaches of the Mare Imbrium. Just to the east of the mountain is the crater Cassini, which serves as a handy reference point when searching for the mountain. Note that while medium to large telescopes is required to spot the 2.3-km high mountain, actually finding it can be challenging in less than favorable illumination. Nonetheless, the image above shows the mountain relative to the terminator, so see if you can spot the mountain after First Quarter when similar illumination will obtain.

Moon Phases

Full Moon
Third Quarter
New Moon
First Quarter
June 5th June 13th June 21st June 28th

Planets in June 2020

– Mercury is now the only planet that is visible in the western sky and will reach its greatest eastern elongation from the Sun on the 4th of the month when it will have an angular diameter of +1.0, and an illuminated phase of 37%. However, by the 12th, the little planet will start dropping back towards the Sun until the end of the month, at which time it will be completely lost in the Sun’s glare.

Venus is now approaching the Sun and will pass almost in front of the Sun on the 3rd of the month. It will therefore not be visible until the 12th when it will appear as a predawn object about 45 minutes or so before sunrise. At this time, Venus will shine at magnitude -4.1, and have an angular diameter of 55 seconds of arc, although its illuminated phase will be only 3%. However, by the month’s end, its angular diameter will have reduced to 44 seconds of arc, but since its illumination will have increased to 18%, the planet will brighten appreciably.

Mars is still a pre-dawn object in the southeastern sky, rising as it does at about 01:45 (BST). The planet starts the month shining at magnitude +0.0 and an angular diameter of 9.3 seconds of arc. Note that both its angular diameter and brightness will increase as it moves across the constellation Aquarius and into the constellation Pisces, which it will reach on the 25th of June. Depending on seeing conditions, it should become easier to spot major Mars surface features such as Syrtis Major as the month progresses.

 – Jupiter starts the month rising about 30 minutes or so before Saturn, but note that its brightness will increase very slightly from magnitude -2.6 to magnitude -2.7, even though its angular diameter increases to 47.2 seconds of arc from 44.7 seconds of arc. Despite the planet being be relatively easy to spot because of its retrograde motion through the constellation Sagittarius, it will remain at or below about 12 degrees above the horizon throughout June, making it difficult to get clear views of the King of the Planets.

Saturn starts the month rising at 01:40 (BST), which is shortly after Jupiter. The planet will rise progressively earlier until, by month’s end, it will rise at around 11 PM (BST), while its brightness will increase from magnitude +0.4 to magnitude +0.2. While the ring system is still tilted towards our line of sight by about 20 degrees, the planet will remain at or below about 10 degrees above the horizon, which could make it difficult to obtain even reasonable views of the planet and its rings.

Meteor Showers in June

The June Bootids, a minor and generally unproductive meteor shower, is expected to peak on the 27th of the month. Otherwise, no other significant meteor activity is expected to occur in June.

Deep Sky Objects to Look For in June 2020

Prominent northern hemisphere constellations at this time of the year include Hercules, Boötes, Sagittarius, Scorpio, Ursa Major, and Ophiuchus. Collectively, these constellations contain many spectacular deep sky objects and a large selection of Messier objects, most of which are easy targets for modest amateur equipment, including binoculars. Below are some details of a few such objects in the constellations Hercules and Ophiuchus-

The Great Globular Cluster – Messier 13 (M13, NGC 6205)

Messier 13
Image credit: NASA

Also known as the Great Hercules Cluster, this collection of about 300,000 stars is located about 22,200 light-years away in the constellation Hercules. While this is not the biggest of the Milky-Way’s globular clusters, it is among the biggest, spanning as it does, about 145 light-years, which makes it easy to find with small telescopes.

The cluster is famous for the fact that a message was beamed to it from the Arecibo radio telescope, on the assumption it was likely that the cluster might contain inhabited planets. However, by the time the message reaches the cluster in 20,200 years, the cluster will have moved to a different position, meaning that the radio message will miss the cluster by somewhat more than a country mile.

Messier 92 (M92, NGC 6341)

Messier 92
Image credit: NASA

Located about 27,000 light-years away in the constellation Hercules, this magnitude 6.3 globular cluster is among the brightest of the Milky Way’s globular clusters. M92 is also among the oldest, being an estimated 14.2 billion years old. Although its estimated age makes it as old as the Universe itself, the large uncertainties in the age of both the cluster and the Universe mean that it did not form before the rest of the Universe; its high estimated age only means that it must have been among the first clusters of stars to form, probably within the first billion years after the birth of the Universe.

Snake Nebula – Barnard 72

Snake Nebula
Image credit: Friendlystar at Wikipedia.org

Located in the constellation Ophiuchus, this snake-like dark nebula is a part of the larger Dark Horse Nebula. The Dark Horse Nebula also contains the Pipe Nebula, of which the Snake Nebula is a part. Nonetheless, the most remarkable aspect of the Dark Horse Nebula complex is the fact it contains a large number of small dark nebulae, like the three that are arranged along an arc directly below the Snake Nebula.

If you can’t immediately find the Snake Nebula, look for the larger Dark Horse Nebula directly to the left of the Barnard 68 molecular cloud. Then locate the Pipe Nebula as the hind-quarter of the horse-like shape; once you have identified the Pipe Nebula, the Snake Nebula should almost jump out at you, so don’t forget to duck!.

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