The night sky in June 2020

posted 30 May 2020, 13:04 by Pete Collins   [ updated 31 May 2020, 05:28 ]
by Anne Holt

Sunrise      1st:   04.46         30th:  04.44
Sunset       1st:   21.27         30th:  21.40

Astronomical darkness: none. In the later part of the month we only have about 2 hours of astro twilight.

Day length      1st:  16.41.24       30th:  16.58.42
Longest day   20th: 17.01.50   (21st is less than 1 second shorter)

Earliest Sunrise     17th:  04.39
Latest Sunset        24th:  21.42

The Summer Solstice, when the Sun reaches its most northerly point in the sky, is on 20th at 22.27.  On this day the Sun is overhead at local noon along the Tropic of Cancer.

Full Moon       5th at  20.12    (366564 Km)
New Moon    21st at  07.42   (387066 Km)

Lunar perigee     3rd  (364365 Km)    30th  (368957 Km)
Lunar apogee   15th  (404596 Km)

June's full Moon is known as the Strawberry Moon.  Other names are the Rose Moon, Hot Moon, Mead Moon and Honey Moon.

On 5th June there is a partial penumbral lunar eclipse.  There will be only a very slight darkening of the right hand side of the Moon's disc as it passes through the outer part of the Earth's shadow.  And, even worse, from Manchester the eclipse will be almost over when the Moon rises at 21.21 - it finishes at 22.04 when the Moon is still only 4 degrees above the SE horizon.  

On 21st there is an annular solar eclipse, visible only from parts of Africa, the Middle East and Asia. An annular eclipse occurs when the Moon is fairly close to apogee so does not appear large enough to completely cover the Sun.  On this occasion the Moon will have 99.5% the diameter of the Sun so, at maximum, will leave only a very thin 'ring of fire'.  The best view will probably be from Tibet where the high altitude means clear air and clear skies.

Highlights

Not much in the way of highlights again this month.  As always in June, the main problem is too much light, no astronomical darkness and very little astro twilight.  Mercury starts the month a day past its highest point in the evening sky but is still very low as the sky darkens.  Early risers fare a little better, Jupiter is still very bright in the early hours and Mars is brightening and getting higher in the pre dawn sky.  We have about 40 minutes of a partial penumbral lunar eclipse and an annular solar eclipse which isn't visible at all from here.  And C/2020 F8 (SWAN) is the latest in a long line of comets which fail to live up to earlier promise.
However, we might see some ...

Noctilucent Clouds
The season for observing these thin, wispy clouds runs from late May to early August.  They may, if we're lucky,  be seen in the north to NW, about 60 to 90 minutes after sunset, and in the north to NE, 90 to 60 mintes before sunrise, when the Sun is about 6 degrees below the horizon. They are usually blue and silver but occasionally red or orange.  They are composed of ice crystals in the mesosphere about 50 miles up - so high that they are still in sunlight when the Sun has set for observers at ground level.
They are formed when water vapour condenses on to dust particles and freezes in the very low temperatures, around minus 120 degrees C.
Some of the water vapour may be moisture from gaps in the troposphere but it is thought to be predominantly produced by chemical reactions involving methane.  Displays became more prominent in the first half of the 20th century when the amount of methane in the upper atmosphere increased.
The dust is mostly of meteoric origin, though some could be atmospheric pollution, the first recorded sighting of the clouds was in 1885, soon after the eruption of Krakatoa.
As well as high methane levels increasing the amount of moisture in the mesosphere, the amount of carbon dioxide also affects the formation of NLCs, high levels of the gas make it even colder which helps the ice crystals to form. 
Displays are stronger and more frequent when, as now, we are close to solar minimum.
Last year we had some exceptional displays, the clouds were seen much further south than ever before, however recent atmospheric studies have suggested that 2020 won't equal these, so we should expect only average displays.
But, recent satellite images have shown the first faint NLCs of the season, above the Arctic Circle, on May 17th, this is very early so you never know.

Update:  these are now intensifying  for up to date information see

Constellations

The Plough asterism in Ursa Major is still prominent, being overhead for much of the night, leaving Cassiopeia on the opposite side of the Pole Star, low in the northern sky. The Summer Triangle, consisting of Vega, Deneb and Altair, is now getting higher in the late evening, though Altair, in Aquila, is still quite low in the early part of the night.  The beautiful double star Albireo, at the head of Cygnus the swan, is very well placed for observing. The Milky Way is now visible from dark sky sites, running across the sky through the Summer Triangle, passing almost overhead in the early hours. The bright orange red Arcturus is shining brightly high in the SW and, if you manage to find some dark skies not obscured by cloud, you should be able to see the rest of the kite shaped Bootes, with the semicircle of stars forming Corona Borealis just to the east of it. Another red giant, Antares in Scorpio is now visible low on the southern horizon.

Planets

Mercury:  in Gemini, mag 0.1
Not easy to see this month.  On 1st it is only 7 degrees above the horizon at dusk, setting at 23.29, a couple of hours after the Sun. It reaches greatest eastern elongation on 4th, when it appears separated from the Sun by  23.6 degrees but only 15 degrees above the horizon at sunset, down to 6 degrees by the time the sky darkens.  From mid June it is below the horizon at dusk. It also fades during the month and on 22nd it is down to mag 3.2  and appearing only 13 degrees from the Sun.  It is at aphelion, the furthest point in its elliptical orbit from the Sun, on 23rd, when it is at a distance of 0.47 AU.  On 30th it sets 20 minutes after the Sun and the apparent separation is only 4 degrees.

Venus:  in Taurus, mag -3.8
Not visible in early June.  On 1st it sets less than half an hour after the Sun and is separated by only 4 degrees.  It reaches inferior solar conjunction on 3rd, passing less than half a degree north of our star.  It then becomes a morning object but too low in the dawn sky to be visible. On 19th at 08.40 (from the centre of the UK - couldn't find local time) in daylight, the planet is occulted by the thin crescent Moon.  At dawn on that day the pair are separated by less than a degree but only 2 degrees above the horizon.  On 30th Venus has brightened to mag -4.4, rising at 03.08 and reaching 7 degrees as the sky brightens.

Mars:  in Aquarius, mag 0.0
On 1st when it rises at 02.14 and should be visible from 03.30, when it reaches 12 degrees in the SE.  On the morning of 13th, the 51% Moon passes 3 degrees south of the planet, now at mag -0.2, in the early hours.  If you look through binoculars you might have a chance of seeing the much fainter Neptune 1 degree 44' to the north.
WARNING:  the Sun rises soon after 4.30 on this day so be sure to put your binoculars away in good time.  Looking at the Sun, even for a few seconds by accident, through binoculars could result in permanent blindness. 
Mars moves into Pisces on 25th, where it rises at 01.27 and reaches 21 degrees by dawn.  On 31st it is at mag -0.5, rising at 00.52 and getting to 24 degrees in the SE as the sky brightens.

Jupiter: in Sagittarius, mag -2.6
Still shining brightly in the morning sky. On 1st it rises at 00.24 and is visible from 01.45 till dawn, when it is at 14 degrees in the south. On 8th the 89% Moon passes just over 2 degrees south of the planet, they are closest at 18.46 while still below the horizon but not much further apart on the morning of 9th.  During the last week in June, Jupiter is less than 1 degree north of Pluto.  They are in conjunction (having the same right ascension) on 25th at 19.32 but at their closest on the morning of 27th.  On this day Jupiter rises at 22.32 and reaches 14 degrees in the south at 02.32.  Unfortunately Pluto will be too faint to be easily imaged at this low altitude.  On 30th Jupiter has brightened to mag -2.7, rises at 22.19 and reaches 8 degrees in the SE by 23.45, culminating at 14 degrees at 02.18.

Saturn:  in Capricorn, mag 0.4
Still low in the morning sky. On 1st it rises at 00.37 and should be high enough to be seen by around 02.30 and getting to 15 degrees in the south by dawn.  On 9th the Moon passes 2 degrees 38' south of the planet at 03.53, with Jupiter also close by, a few degrees to the west.  The Moon will be 86% lit, so no smiley face. By 30th Saturn will be at mag 0.2, rising at 22.35 and culminating, 16 degrees above the southern horizon, at 02.44.

Uranus:  in Aries, mag 5.9
Not visible this month.  On 1st it rises at 03.31 but is still 10 degrees below the horizon at dawn.  It does improve during the month but is still only just on the horizon at daybreak on 30th.

Neptune:  in Aquarius, mag 7.9
On 1st it rises at 02.17 and is still below the horizon when the sky begins to brighten.  On 12th at 13.18 Mars passes 1 degree 44' south of the fainter planet, they are still close on the morning of 13th, when Neptune rises at 01.30 but doesn't get high enough in darkness to be an easy binocular target.  On 30th it rises at 00.24 and gets to 9 degrees by dawn, still a bit too low for observing.  


Dwarf Planets

Ceres:  in Aquarius, mag 9.0
Rises at 03.01 on 1st but is still very low in the SE by dawn. On 30th it rises at 01.27, has brightened to mag 8.6 but still doesn't get high enough for imaging or observing.

Pluto:  In Sagittarius, mag 15.0
Orbiting in the Kuiper Belt, the faint, distant Pluto is much too low to be successfully imaged, even towards the end of the month when it is very close to Mars.

Haumea, in Bootes, mag 17.3, and Makemake in Coma Berenices, mag 17.1, are much higher in the sky and a better bet for ambitious, experienced amateur astrophotographers, despite being so distant and faint. On 1st Haumea is at 50 degrees in the SW around midnight, Makemake reaches a similar altitude.  By month end the highest points in darkness are 32 degrees and 27 degrees in the west respectively.

Eris: in Cetus, mag 18.8
The faintest, most distant of the currently recognised dwarf planets is below the horizon all night throughout June.

Asteroid 7 Iris, in Sagittarius, reaches opposition on 28th.  On this day it is at mag 8.9 and culminates at 01.14 but is only 15 degrees above the southern horizon.

Comets

C/2019 Y4 (ATLAS) in Taurus.
Originally predicted to be a candidate for Comet of the Century,  then it broke up.  But the 4 main pieces are still going and are quite bright at magnitudes ranging from 3.8 to 5.9.
But we can't see them, as they are now too close to the Sun.

C/2017 T2 (PANSTARRS) in Ursa Major, mag 8.8
Circumpolar at the start of June, and reasonably high during the hours of darkness . By 6th it is quite low for part of the night and best seen between midnight and 2am. Moves into Canes Venatici on 25th, when it will have faded slightly and only be high enough from 01.00 to 01.30.  On 30th it is predicted to have faded to mag 9.2 and will be best positioned between 00.40 and 01.40.

C/2020 F8 (SWAN) in Auriga, mag 6.4
Yet another which hasn't lived up to expectations, estimates now a couple of magnitudes less than previously given. On 1st it is circumpolar, just over 1 degree SW of Capella, only 11 degrees above the horizon as the sky darkens. It is moving south westwards, getting lower in the evening sky.  On 23rd it moves into Lynx and is only 9 degrees at dusk.  It goes back into Auriga on 28th  and on 30th, now with an estimated mag of 8.1, appears only 9 degrees from the Sun.

For more info and exact positions of any solar system objects see

I usually recommend www.cometwatch.co.uk but as it hasn't been updated since April 20th, maybe not.
If I've missed any current comets - blame them!

Meteor Showers

Not a good month for meteor spotters. The antehelion source may provide one or two, especially in early and late June but the radiant, moving across Sagittarius, is very low for observers in the northern hemisphere.

June Bootids, active (maybe) June 22nd to July 2nd, peak on the night of 27th around 23.00.  ZHR is variable, given as anything between zero and 30, but this year is predicted to be at the lower end of that range, though there could possibly be some activity on 23rd.  The parent comet of these slow moving meteors is 7P/Pons-Winnecke.

June Lyrids, peak 15th/16th.  Not much activity from these in recent years.

There are a few daytime showers:

Zeta Perseids,  active May 20th to July 5th. peak 9th (or maybe 13th).  This shower, parent comet 2P/Encke, was first discovered at Jodrell Bank in 1947.

Beta Taurids,  active June 5th to July 18th, peak 28th.  ZHR said to be 'weak' or 'modest' but it is thought that the Tunguska meteor in June 1908 could have been associated with this shower.

Daytime Arietids, active May 14th to June 24th, peak June 7th,  ZHR 30.
A few of these may be spotted visually in the morning twilight but the radiant is only 30 degrees west of the Sun.
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