Night Sky Notes – May 2019

Night sky notes for May 2019         Geoff Mitchell

The May night sky shows the summer constellations rising  mid evening and the spring constellations heading into the western twilight  The red planet Mars is located low in evening twilight moving from Taurus eastward into Gemini throughout the month . The bright planet Jupiter is now low in the south by midnight in late May, reaching opposition in the constellation of Ophiuchus in early June.  Binoculars show a tiny disk and the four Galilean moons Io, Europa, Ganymede and Callisto changing position evening to evening as they orbit the giant planet. Telescopes reveal the most prominent cloud belts in the equatorial region and the subtle straw coloured `Great Red Spot`. At favourable times the Galilean moons cross in front of Jupiter (as seen from Earth), these transit events can also produce shadows cast onto the cloud tops. To observe these shadow transits requires a moderate telescope (20cm aperture or larger) and moderate magnification (x 150).

The late spring night sky contains many fine objects to view but also has a few notable events of special interest.   From late May onwards Look to the NW some 90 to 120  minutes  after sunset  or to the NE before sunrise  i.e. when the Sun just below the horizon during the summer months when 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.

The constellation of  Virgo due south as twilight fades contains a large cluster of Galaxies , the Virgo Super cluster , visible as faint misty patches in moderate sized telescopes – the bright late evening skies however makes observing these quite a challenge . Our own Milky Way galaxy stretches from the constellation of Auriga [The Charioteer], marked by the bright star Capella and through the constellations of Perseus and Cassiopeia all now positioned low in the north.  In the south the night sky looks outward to the distant galaxies of the Virgo and Coma cluster.

In the east the summer constellation of Cygnus [The Swan] now rises by late evening. The bright star Vega in the adjacent constellation of Lyra [The Lyre] is seen low above the north east horizon and Altair in the constellation of Aquila low in the east. Vega, Altair and Deneb, in the constellation of Cygnus form the `Summer Triangle` asterism, a useful sign post for the summer skies.  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 .

Scorpius [The Scorpion] in part is visible low in the south 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. The red star Antares, the name means `rival to Mars ` the characteristically deep red in colour is easily seen in binoculars.  Also of interest is the nice globular cluster M4 , lying close to Antares and also at opposition in May several bright (binocular /telescopic)  asteroids  including  No 20 Massalia close to β  Scorpii [ Graffias]. Several more bright asteroids are located in the adjacent constellation of Libra and include Asteroid No 8 Flora and No 11 Parthenope. Newsletters 217 and 218 available to LAS members. Dwarf planet Ceres also reaches opposition as a 7th magnitude star like point visible in binoculars seen to move night to night against the background stars in the constellation of Ophiuchus  , close to the star  Graffias in the `head` of Scorpius  (see Notes)

Look low in the SE by midnight in late May to find the summer constellation of Sagittarius [The archer], adorned with rich Milky Way star fields and star clusters visible in binoculars. The constellation contains the famous `Teapot ` asterism with the Milky Way appearing as the steam rising from the spout . Located in the handle of the `Teapot` is a yellowish star which is in fact the ringed planet Saturn which reaches opposition in late July.. Although rather low as seen from the UK, its ring system is now wide open, a classic view of this gem of the solar system. Small telescopes 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.

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]. The faint 11th magnitude star T Coronae Borealis ` Blaze Star` is a  reoccurring nova  (eclipsing binary star system)  that periodically sheds material and brightens to 2nd or 3rd magnitude; the last two outbursts were in 1866 and 1946.

 

 

Planets in May 2019

Mercury is glimpsed low in evening twilight in late May after superior conjunction on May 21

Venus is visible very low in dawn twilight. (Poorly placed), phase increases to 93% by month end.

Mars is located in evening twilight, moving eastward into Gemini during May

Jupiter is now low in the south in the constellation of Ophiuchus by midnight in late May, nice telescopic views.

Saturn rises by midnight by late May, low in Sagittarius – rings remain wide open in 2019 – Nice.

Uranus reached conjunction in April, visible again in autumn evening skies.

Neptune reached conjunction in March, visible again in autumn evening skies.

Dwarf planet Pluto reaches opposition on mid July (Mag 14.5) in Sagittarius.

Moons phases in May  2019

New Moon         May 4th               Moonless, best time for deep sky observing.

First Quarter     May 12th             Best days to see shadow details in lunar craters (early evening)

Full Moon            May 18th             Best days to see bright ray craters like Copernicus / Tycho.

Last Quarter      May 26th             Moon visible in daytime skies.  Do not look directly at the Sun.

 

Meteor shower s       η Aquarids – peak May 5th, range April 24th to May 20th – ZHR 40/ hour (low in UK skies)

α Scorpiids maxima April 28th – May 12th, low rates only ZHR  just 5

 

The highlights of the month.

Jupiter is low in the south by midnight with cloud belt features and moons visible in modest telescopes.

Saturn low in south east by midnight  , rings open at 23° DE [tilt] showing Saturn’s North Pole.

Noctilucent cloud – from late May watch the NW skies 2 hours after sunset (see text)

A thin  4% waxing crescent Moon visible after sunset on May 6th , note the dimly lit Earthshine.

 

Crescent Moon visibility,

A very thin 0.9% waxing crescent Moon is located low in western skies after sunset from around 20.45 until moonset is 21:06 on May 5th but is very  difficult to see in bright twilight.

 

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, check the  home page for posting s of details of favourable observing times.

 

 

Sky looking south at 10pm British Summer Time (BST), early May 2019

High in the south note the orange star Arcturus in the constellation of Bootes (The brightest star north of the celestial equator.)

Looking  at Virgo we look outside our own Milky Way galaxy towards the external galaxies of the Virgo Cluster , look  to Sagittarius  to into the spiral arm of our own galaxy, the centre of our own galaxy is however too far south to see from the UK  .  Markarian’s chain is a line of brighter galaxies between the stars Vindemiatrix and Denebola.

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).

The obscure constellation of Coma Berenices is famed for the nice binocular cluster Melotte 111 and also hosts a number of ` brighter` galaxies of the Coma Cluster of Galaxies. The NGP (North Galactic Pole) is located in Coma Berenices – the observer is looking outward from our own Galaxy –The Milky Way.

 

 

 

 

Sky looking east at 10pm BST mid May 2019

 

In May the summer constellations of Lyra and Cygnus are rising by late evening, the Milky Way may be visible on moonless evenings from a dark site.  Constellation of Hercules high in the east contains two fine Globular Clusters M13 and M92 visible to small telescopes as fuzzy patches; moderate telescopes resolve the clusters into a myriad of stars.

Locate the `Keystone` Asterism in the constellation of Hercules. Find 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.

 

By midnight the constellation of Scorpius rises low in the southeast aspect – Red star Antares is easily identified and the bright planet Jupiter is also visible low in UK skies.

 

Each circle represents the apparent field of view of typical 10 x50 binoculars

Sky looking north at 10pm BST early May 2019

The Plough asterism (Constellation of Ursa Major). Follow the two pointer stars 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 north western horizon.

 

Sky looking west at 10pm BST mid May 2019

 

Mars is visible in evening twilight throughout the month , moving eastward from Taurus into Gemini