Night Sky Notes March 2017

Night Sky Notes for March 2017                 Geoff Mitchell

The March night sky now heralds the spring constellations as we head towards the vernal equinox on March 20th marking the start of spring in the northern hemisphere. The planet Venus is seen telescopically as a thin crescent early March before conjunction on March 25th. Mercury is visible after sunset from mid month low in evening twilight. The spring night sky contains many fine objects to view with both binocular and small telescopes and this month has a few notable events of special interest. Clocks go forward Sunday March 26th marking the beginning of British Summer time (Daylight saving time if you use a GOTO instrument) . Additional interest is provided by binocular comet 41P (Tuttle-Giacobini-Kresak) and telescopic comets 45P (Honda-Mrkos-Pajdusakova) and comet 2015 V8 (Johnson).

The Milky Way stretches from the constellation of Auriga , marked by the bright star Capella in the east up into Perseus and through the `W` shaped constellation of Cassiopeia high overhead and down along the cross shaped constellation of Cygnus low in the northwest . This faint band of stars is best seen on dark moonless evenings.

In the north Ursa Major, The Plough or The Great Bear is seen low with its handle or tail pointing to the horizon 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. In late March Comet 41P passes within 0.14 AU, 21million km (13 million miles) of Earth (pre perihelion) and may brighten to binocular or naked eye visibility close to the star Dubhe. (See notes)

Also in the south west, the seven sisters’ (Pleiades, M45) star cluster and constellation Taurus .The Hyades, the nearest open star cluster to Earth, makes the characteristic `V` shaped asterism in the constellation of Taurus and is noted for the bright, red foreground star Aldebaren. In Arabic Al Dabaran is `The follower ` of the Pleiades across the skies, in old English colloquially known as `the eye of the bull`. By early evening the familiar winter constellations of Orion (The Hunter) are now slipping into the western skies making way for the spring constellations rising in the east. Follow a line drawn through the constellation of Orion, from Rigel (lower right) upward through the red super giant star Betelgeuse ( upper left) extend this to find the two stars Castor and Pollux in the constellation of Gemini . Gemini resembles a long rectangle with Castor and Pollux at the left hand side , the right hand end straddles the rich star fields of the Milky Way and has some notable star clusters , for example M35 visible in binoculars or small telescopes .

Draw a line from Pollux down to Regulus in the constellation of Leo; about half way along the line you will see a misty patch with the unaided eye on dark moonless evenings. Look with binoculars and see the open star cluster M44 (the Beehive cluster) or Praesepe in the obscure inverted `Y` shaped constellation of Cancer [The Crab].

The spring constellation of Leo rises by early evening, the brightest star Regulus and the `reversed question mark ` shaped star asterism of `The Sickle` makes this an easily recognisable constellation. Leo stretches eastward and is marked at the tail end by the star Denebola. Leo contains some moderately bright galaxy pairs visible in moderate sized telescopes on moonless evenings. M65/M66 and NGC 3628 form the famous galaxy triplet, all three galaxies being visible in the same telescopic field of view. The star Algieba in the Sickle is a nice double star with golden yellow components visible at moderate magnification in a 100mm telescope.

Jupiter positioned low in the constellation of Virgo rising mid evening it is however not well placed for observing / imaging from UK. Small telescopes show the four bright moons discovered by Galileo in 1610 and the famous cloud belts. The Great Red Spot is currently more subtle and straw coloured. Jupiter’s Galilean moons show shadow transits and go into eclipse behind the as seen from Earth. A 21cm aperture or larger telescope is recommended to see the tiny dark shadow disks of the Galilean moons cast onto the cloud tops of Jupiter turbulent atmosphere.

The constellations of Virgo and Coma Berenices now rise by late evening and corresponds to a view looking out of the plane of the Milky Way galaxy to other galaxies within the Virgo super cluster of Galaxies of which the galaxies of our local group are distant members . The Virgo cluster of Galaxies has many relatively bright galaxies visible in moderate sized telescopes on moonless clear evenings. (See notes)

Planets in March 2017

Mercury reaches Superior Conjunction on March 7th and emerges into evening twilight skies mid March.

Venus reaches Inferior Conjunction on March 25th, visible as a thin crescent early March until March 18th .

Mars is just visible very low in the west in evening twilight in March. (see Notes)

Jupiter shines brightly low in the east in the constellation of Virgo mid evening from mid month. (Public open evenings for are planned for March 15th and March 23rd – see www.lutonastrolink.org.uk )

Saturn now rises early morning in March and will be positioned low in spring / summer skies. Saturn is located on the border of the constellations of Sagittarius and Ophiuchus, opposition is June 15th.

Uranus is now lost to evening twilight low in the west – best seen in autumn skies

Neptune sets with the Sun in March and is then in our daytime skies – best seen in autumn skies

Moons phases in March 2017

New Moon Mar 28th Moonless, best time for deep sky observing and galaxy hunting.

First Quarter Mar 5th Best days to see shadow details in lunar craters (early evening)

Full Moon Mar 12th Best days to see bright ray craters like Copernicus / Tycho.

Last Quarter Mar 20th Moon visible in daytime skies. Do not look directly at the Sun.

Meteor shower s Virginids show some slow meteors with long trails, peaking during April.

The highlights of the month

  • Look at the thin crescent Moon on March 29 th to see the Earthshine effect – the non sunlit part of the Moon seen in faint detail illuminated by reflected sunlight from Earth. Also see Mercury to the right of the Moon and Mars above the Moon in twilight skies on this date.
  • March skies, Milky Way visible high overhead on moonless evenings in darker skies.
  • Jupiter returns to our evening skies, cloud belts and four of Jupiter’s moons visible in a small telescope and the prospects of observing some shadow transit events using larger telescopes.
  • Comet 41P ( Tuttle-Giacobini- Kresak) reaches perihelion in mid April , but has a close approach ( 0.14AU ) with Earth in late March and will be well placed for observing in the constellation of Ursa Major ( Binocular required – see notes)
  • Double cluster, on the Perseus /Cassiopeia border high overhead, nice pair of star clusters.
  • Pleiades (Seven Sister’s) star cluster (M45) now low in south west, best seen with binoculars.
  • Beehive cluster (M44) visible to the unaided eye but best seen with binoculars.
  • Telescopic triplet of galaxies M65/M66/NGC3628 in the constellation of Leo
  • Looking outward from the plane of the Milky Way galaxy, the Virgo Cluster of Galaxies is now visible early evening, best explored on dark, clear moonless evenings.
  • Those who are supporting WWF Earth Hour events including the Lights out event (Saturday 25th March 2017 8.30pm to 9.30pm ) may like arrange observing with friends and family and take a look at the March night sky.
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