Night Sky Notes – June 2018

Night sky notes for June 2018         Geoff Mitchell

The June night sky shows almost continuous twilight, the summer solstice on June 21st marks the shortest night. The bright conditions limit observations to the planets and brighter stars.

Venus shines brightly low in western evening twilight and has decrease in apparent phase from 80% to 70% during the month.  Mercury moves back into evening twilight from mid June onwards ,

The bright planet Jupiter in the constellation of Libra is now low in the southwest by early evening. Small telescopes show up to four prominent Galilean moons Io, Europa, Ganymede and Callisto as well as the famous cloud belts. The Great Red Spot (GRS) is less prominent and may require larger telescopes to see at favourable times – Jupiter rotates in just less than 10 hours. Under favourable conditions eclipses and occultation’s of the Galilean moons may be seen including shadow transit events as a small dark shadow of one of the moons is cast onto the cloud tops.- larger telescopes required.

Look low in the SE late evening to find a yellowish star to the east of Sagittarius. The yellow star is in fact the ringed planet Saturn which reaches opposition in late June].  Although rather low as seen from the UK modest telescopes give a classic view of this gem of the solar system and will show the rings and the brightest moon Titan. Larger telescopes show up to six or so fainter moons and any white oval features on the planets disk and some of the ring detail such as Cassini Division etc.  Observe the Seeliger Effect around opposition to mid and note any brightening of the ring system due to the ring particles angle of illumination changing causing the apparent brightening.

Scorpius [The Scorpion] in part is visible low in the south as twilight fades. Use binoculars to see the myriad of stars in these rich star clouds, best seen on clear dark moonless evenings from darker locations outside the town or remember to take your binoculars with you if you’re on your holidays. The red star Antares, as the name means `rival to Mars ` currently this can be compared with the planet Mars which  rises around midnight  during the month and is currently located in the constellation of Capricornus. Mars reaches opposition in July but is placed very low in UK skies.

The summer night sky contains many fine objects to view for the enthusiast in the midnight hours but also has a few notable events of special interest.   During June look to the NW some 90 to 120 minutes after sunset or to the NE 90 minutes similarly before sunrise. This when the Sun is just below the horizon during the summer months , under favourable conditions  extremely high clouds at 80 km altitude known as Noctilucent Cloud (NLC) may be seen. NLC’s show a bluish colour and also show filamentary structure.

In the south west the constellation of Virgo as twilight fades contains the white star Spica and the Virgo Cluster of Galaxies , the light sky conditions however mean that even at midnight the fainter objects are `difficult ` to view even with larger aperture telescopes.

Our own Milky Way galaxy stretches from the constellation of Auriga [The Charioteer], marked by the bright star Capella through the constellations of Perseus and Cassiopeia all now positioned low in the north. In the east however the summer constellations of Cygnus [The Swan or Northern Cross] now rises by late evening. The bright star Vega in the adjacent constellation of Lyra [The Lyre] is seen in the north east and Altair in the constellation of Aquila low in the east by late evening. Vega, Altair and Deneb, in the constellation of Cygnus form the `Summer Triangle` asterism, a useful sign post for the summer skies. Look with binoculars along the central axis of Cygnus , down through Aquila into the south and see the rich star fields of Scutum and Sagittarius , with the famous `Teapot ` asterism,  low in the south in the early morning hours in June and late evening in July.

Adjacent to  Lyra the familiar `keystone asterism ` of the constellation  Hercules is noted for the Globular clusters  M13 and M92 the former containing some 750,000 stars, a nice view in a small telescope .

The familiar asterism of the plough in the constellation of Ursa Major, The Great Bear is seen high overhead with its handle or tail pointing upwards mid evening. Use the right hand pair of stars Dubhe and Merak (The pointers) to find the faint pole star Polaris and the position of North.

High in the east the bright orange star Arcturus in the constellation of Bootes [The Herdsman] is the brightest star in the northern hemisphere of the sky.  Between Arcturus and the Keystone asterism in Hercules lies the `U` shaped constellation of Corona Borealis [Northern Crown].

 

 

 

Planets in June 2018

Mercury  emerges in evening twilight skies from mid June  reaching greatest elongation on July 12th .

Venus shines brightly low the NW  in evening twilight , telescopes show a 75% phase during June

Mars  now rises by midnight in June , opposition is in late July , unmistakably red brightening to -2m .

Jupiter shines brightly in the SW in evening twilight , telescopes show cloud belt detail and Galilean moons.

Saturn now at opposition (June 27th) rises by mid evening in Sagittarius low in south. Although it is low in our June skies but has the ring system open at 26 degrees – a classic view of this `gem ` of the solar system.

Uranus is not visible in pre dawn skies – best views in autumn skies.

Neptune is not visible in pre dawn skies – best seen in autumn skies

Moons phases in June 2018

New Moon         June 15th             Moonless, best time for deep sky and Milky Way observing.

First Quarter     June 22nd            Best days to see shadow details in lunar craters (early evening) **

Full Moon            June 29th             Best days to see bright ray craters like Copernicus / Tycho.

Last Quarter      June 8th               Moon visible in daytime skies.  Do not look directly at the Sun.

Meteor shower s        Ophiuchids – peak June 10th to June 20th – low rates                                                                                                                      June Lyrids, peak June 16th

The highlights of the month.

Saturn at opposition  low in south east by late evening  , rings open at 26° DE [tilt] showing Saturn’s North Pole.

Jupiter- Telescopes show  the shadow transit of Jupiter’s moon Ganymede  from 22:00 to 23:50 BST on June 18th [20cm telescope or larger}

 

Blood red star Antares in the constellation of Scorpius low in the south in the late evening sky

Noctilucent cloud –watch the NW skies 90 to 120 minutes  after sunset.

Summer solstice June 21st 11:08 BST, earliest sunrise June 17th and latest sunset of the year June 25th.

Waxing  crescent Moon   Venus  and  a  1.7 day old waxing  6.2%  crescent Moon  on June  15th , look low  close to the NW  horizon from 15 minutes  after sunset  from around 21:40 BST  until moonset at 22.:29 BST  Caution.  Do NOT look at the Sun directly with or without optical aid..

Note the waxing crescent Moon has a dimly lit part made visible by Earthshine is readily seen with binoculars or small telescope.  Only look for the crescent Moon after the sun has completely set.

More detailed sky notes and LAS Newsletters, Finder charts are available to LAS members via the Members` page on the LAS Website www.lutonastrolink.org.uk  Artificial satellite and International Space Station visible passes and bright Iridium flares – check the  home page for posting s of details of favourable observing times.


 

Sky looking south at 11pm British Summer Time (BST), mid June 2018

In the south the ringed planet Saturn lies in the constellation of Sagittarius famed for its rich star fields.

The orange star Arcturus is found by following the curve of stars in the handle of the Plough down. The constellation of Bootes, resembles a `kite` or `Club ` in shape.   The star Izar is a beautiful orange/ blue double star visible in small telescopes. To the east of Bootes find the `horseshoe` shaped constellation of Corona Borealis (Northern Crown) and the `Keystone` Asterism in the constellation of Hercules. Hercules also has M13 the famous Globular Cluster, visible to the unaided eye as a misty patch; telescopes show the true wonder of this cluster with over 750,000 stars. Likewise another nice globular is M92 in Hercules.

 

Sky looking east at 11pm BST mid June 2018

In June the summer constellations of Lyra and Cygnus are rising by mid evening, the Milky Way may be visible on moonless evenings from a dark site, subject to twilight. Binoculars show the rich star fields of the Milky Way.

The Summer Triangle asterism formed by the three bright stars Vega, Altair and Deneb is a useful guide for finding your way around the summer night sky

Periodic Comet 29P Giacobini –Zinner is faint , magnitude brightening to 10.7m by month end ( 20cm or larger telescope required ) – The comet will be better placed in our late summer skies in moonless dark skies .

 

 

Sky looking north at 11pm BST mid June 2018

The Plough stands with its handle pointing upward follow the pointer’s Dubhe and Merek to find the polestar Polaris. The `W` shaped constellation of Cassiopeia is at its lowest point in the north late evening.  The Milky Way follows the galactic equator and stretches from east through the constellations of Cygnus, Cassiopeia, Perseus and down into the northern horizon.

 

Sky looking west at 11pm BST mid June 2018

The orange star Arcturus is found by following the curve of stars in the handle of the Plough down. The constellation of Bootes, resembles a `kite` or `Club ` in shape.

 

 

Night sky highlights of the month June 2018

Saturn visible low in the SE late evening, reaches opposition in mid June the planet shows nice ring detail and northern polar region. Titan is the brightest of Saturn’s moons which is visible in a small telescope and moves from evening to evening with respect to the planet, orbiting Saturn in just 15.9 days.

 

 

WINJOPOS software prediction for telescopic view Saturn’s moons for June 14th (Titan is at greatest elongation ) and Jupiter at 23:00 BST on June 18th  showing the shadow transit of Jupiter’s moons Ganymede near the north polar region .

 

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