Night Sky Notes February 2017

 Night sky notes for February 2017                     Geoff Mitchell

The mid winter skies herald the constellations of  Leo,  Cancer , Gemini ,  Auriga , Taurus,  and  Orion   The Milky Way stretches from  `W ` shaped  constellation  of Cassiopeia , through the constellation of  Perseus high overhead down through Auriga and down into Gemini  in the  south  east.

The Moon appears a pale yellow during the Penumbral lunar eclipse, entering the Earth’s penumbra shadow at 10:34 pm (Feb 10th), greatest at 00:44 am  and exiting at 02:53 am (Feb 11th ) , restoring to usual Full Moon brightness after eclipse.

Several telescopic short periodic comets feature in the February skies and one in particular Comet 45P (Honda – Mrkos-Pajdusakova) is likely to become bright enough as a binocular / unaided eye  object as it harmlessly passing Earth during February  at some 12 million km distant at its closest point on February 11th 2017.

Periodic Comet 2P (Encke) is a difficult 12th magnitude telescopic object low in the western twilight skies near the Circlet asterism in the constellation of Pisces. The comet reaches its closest point in its orbit to the Sun (perihelion) in early March.

Periodic Comet 41P (Tuttle-Giacobini-Kresak) passes within 20 million km of Earth pre-perihelion in late March but is telescopic in February. Another comet C/2015 V8 (Johnson) remains telescopic (11.5m) in February.

Taurus has the red star Aldebaren and the V shaped Hyades star cluster, the nearest open star cluster to Earth and the famous Pleiades star cluster (M45) also known as the Seven Sisters cluster.  Taurus can be seen in the east by early evening. Also located in the constellation of Taurus is the Crab Nebula (M1), a supernova remnant shell of expanding gas. The supernova was observed in daylight by the Chinese in the year 1054.

Auriga has the bright star Capella and can be seen overhead and slightly above Taurus.  The rich background of stars of the Milky Way is best seen on moonless evenings from outside the light from the town and the three fine star clusters M36, M37 and M38 can all be seen using binoculars.

In the south  the familiar constellation of Orion can be seen early evening , noted by the three stars of Orion’s belt , the red giant star Betelgeuse  (top left) , the white star Rigel (bottom right ) and the misty patch of the Orion Nebula (M42)  of  the sword  , just below the belt stars.  M42 is a fine object when viewed with binoculars or a telescope, the hot young stars known as `The Trapezium ` light up the surrounding clouds of gas and dust that form the nebula. Follow the line of the belt stars downward to find the white ` Dog star ` Sirius, the brightest star in our night skies.  Below Sirius is M41 an open star cluster for binoculars / small telescope.

Betelgeuse in Orion, Procyon in Canis Minor and Sirius in Canis Major form the winter triangle asterism .

By mid evening, the rectangular shaped constellation of Gemini is well placed.    Use the two stars of Castor and Pollux in Gemini to point to the faint (inverted Y shaped) constellation of Cancer (The Crab) in the east. The Praesepe (Beehive) cluster (M44) can be seen as a misty patch on moonless nights, located in Cancer, about half way between Pollux and the bright star Regulus in Leo rising low in the east. Binoculars show this nice cluster well but it is a wonderful sight in a small telescope.

Low In the north west the familiar circumpolar stars of  Vega  ( in the constellation Lyra ) ,  Deneb ( in Cygnus , or  The northern Cross   dip into evening twilight and appear low in the north by midnight. In the north the constellation of Ursa Major, The Great Bear, with The Plough asterism can be seen low down. standing on its handle  Use the right hand pair of stars  Dubhe  and Merak  (The pointers ) to find the faint pole star Polaris five times the separation of the two stars and hence  the position of North .

The constellation of Leo rises late evening and is easily identified by the reversed question mark asterism known as `The Sickle`  and the bright star Regulus . Leo and Virgo herald the spring skies and the realm of the galaxies of the Virgo / Coma cluster of Galaxies, the brightest members of which can be seen with moderate telescopes on clear moonless evenings.

Venus shines brightly in evening twilight and presents a phase as seen telescopically, this reduces from 40% to just 20% in February and so it is a good time to view . Venus reaches greatest brilliancy around February 17th.

Mars is noticeable by the red colour and is located above Venus in evening twilight but is a poor view presently.

Planets in February 2017  

Mercury is placed low in dawn skies early February heads towards superior conjunction early March

Venus shines brightly in the evening twilight skies; phase reduces to a thin crescent in February.

Mars is visibly red in colour in the southwest in evening twilight skies located above and to left of Venus.

Jupiter in Virgo rises late evening low in UK skies,  a telescops shows the cloud belts and four Galilean moons.

Saturn is low in midnight skies in the constellation Ophiuchus; the ring system is wide open in 2017

Uranus is placed in the constellation of Pisces low in our evening twilight. (Binocular / Telescope required)

Neptune in the constellation Aquarius best seen in autumn.

Moons phases in February 2017

New Moon         Feb 26th                   Moonless, best time for deep sky observing and Comets

First Quarter      Feb 4th                  Best days to see shadow details in lunar craters (early evening)

* Full Moon           Feb 11th             Best days to see bright ray craters like Copernicus / Tycho.

Last Quarter       Feb 18th               Moon visible in daytime skies.  Do not look directly at the Sun

*Penumbral lunar eclipse             Moon enters penumbral shadow at 22:34 GMT and exits at 02:53 (Feb 11th)

Meteor shower s.                            There are no meteor showers only sporadic meteors this month

Highlights of the Month

Venus is at its best in February, small telescopes show a thin crescent. Jupiter rises by late evening and is placed close to the white star Spica.

Observe the winter constellations and many of the fine star clusters such as the Beehive cluster (M44) and Seven Sisters cluster (M45 or Pleiades) and the Orion Nebula (M42 / M43). Also use binoculars to view the many fine objects in our winter night skies.

The bright stars Betelgeuse and Aldebaran   show red and orange colour , whilst the brightest star in the sky Sirius  flashes white / blue `twinkling ` low in our winter skies.

Comet 45P may brighten to binocular visibility during mid February (see notes).  Comet 45P is initially visible in pre dawn skies from around first week in February in the constellation pf Aquila it steadily moves northward through the constellations of Hercules and Bootes during the month. The comet becomes visible as a late evening object from mid month in moonless conditions (see LAS finder chart) , the comet will fade in brightness after mid month as it moves away from Earth. The comet visible as a misty patch is best seen in darker moonless skies in early/ late February; observe away from street lights etc.

Crescent Moon visibility. A 1.6% thin crescent Moon is visible after sunset on February 27th; moon set is 6:50pm.

More detailed sky notes and LAS Newsletters, Finder charts are available to LAS members via the Members` page on the LAS Website