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

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1 Night sky notes for February 2020 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. Planet Mars is located in Aries in early February but is moving eastward into Taurus later in the month. Now well past opposition Mars presents a tiny disk telescopically and is around 1 st magnitude, still an easy spot relatively high in the south west aspect early evening- unmistakable in its red colour, not to be confused with Aldebaren in Taurus also red in colour. Watch Mars track eastward during the next few weeks as it edges closer to the Seven Sisters (M45) (Pleiades) star cluster. The planet Uranus is located in the constellation of Aries, the planets characteristic greenish hue can be seen telescopically as a tiny disc (compared with the pin sharp field stars. Binoculars will also enable identification as a star like point; at 5.8m magnitude it is brighter than the surrounding field stars. (See notes) Taurus also has the foreground red star Aldebaren in line of sight with the V shaped Hyades star cluster, the nearest open star cluster to Earth at a distance of just 150 light years and the famous Pleiades star cluster (M45) also known as the Seven Sisters cluster. Aldebaren name from the Arabic means `the follower `, chasing the seven sisters across the sky. 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 M1 is a difficult, low surface brightness object, moderate telescopes show an oval shape, larger telescopes may show the curved `claw` feature, LPR filters improve the contrast for nebulae in light polluted skies. 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 or small telescopes. 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. In contrast to the bright nebula the dark nebula (of obscuring dust) known as `The Fish Mouth` is readily seen, also note the nearby nebula (M43), its curving shape resembles a comma. 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. A more challenging star cluster is M67 to the south of M44. 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

2 the Virgo / Coma cluster of Galaxies, the brightest members of which can be seen with moderate telescopes on clear moonless evenings. Leo contains the famous `Leo triplet` of Galaxies three edge on spiral galaxies ( M65, M66 and NGC 3628, visible in moderate telescopes within the same field of view (Low magnification ) visible on darker moonless evenings Leo also contains M95, M96 and M105 galaxies and also the striking double star Algieba (γ Leonis), small telescopes requiring higher magnification (x120) to resolve the pair of orange yellow stars. Lunar observers may also note the moons slight `rocking` or libration favours a glimpse of Mare Orientale on the moons SW limb around February 25 th on the day/night terminator. Also the Clair Obscur effect known as the Jewelled Handle (Jura Mountain range) visible on February 21 st Details February Sky at Night magazine. Lunar Occultation of X1 Arietis (5.5m magnitude) disappears behind the moons dark limb at 19:20 (7.20pm), suitable for small telescopes / binoculars this early evening event shows the moons eastward motion relative to the stars. Two asteroids (4) Vesta and (29) Amphitrite are located in Leo in February, Vesta is the brighter at 6.5m magnitude as a binocular / small telescope object, Amphitrite is fainter at around 9.5m requiring moderate telescope observation. Seen as star like points moving evening to evening against the background star fields, asteroid observation/ imaging techniques requires the use of detailed finder charts refer to LAS Newsletters No 281 and 283 respectively to spot the elusive object. Periodic Comet 141P Machholz, moves eastward through Cetus, a low surface brightness coma at 10.5m it is indeed a `faint fuzzy `requiring imaging techniques and larger telescopes details LAS Newsletter No 277A. Similarly periodic comet 156P Russell-LINEAR, moves eastward through Triangulum, at 11.0m (fading), challenging imaging techniques are required, larger telescopes details LAS Newsletter No 270. Planets visibility in February 2021 Mercury is at inferior conjunction 0n February 8 th, returning to dawn twilight by late February. Venus is not visible; it is too close to the Sun during February, emerging evening twilight later in the spring. Mars moves eastward from Aries into Taurus it is red in colour, easily spotted low in the south west early evening. Jupiter is not visible it is too close to the Sun during early February, emerging dawn twilight by late February Saturn is not visible; it is too close to the Sun during early February, emerging dawn twilight by late February Uranus is visible in binoculars as a star like point (tiny telescopic disk), located in Aries see notes Neptune positioned in the constellation of Aquarius lost to evening twilight and is best seen in autumn skies. Moons phases in February 2021 New Moon Feb 11 th Moonless, best time for deep sky observing and Comets First Quarter Feb 19 th Best days to see shadow details in lunar craters (early evening) Full Moon Feb 27 th [Snow Moon] Best days to see bright ray craters like Copernicus / Tycho. Last Quarter Feb 4 th Moon visible in daytime skies. Do not look directly at the Sun Meteor shower s. There are no meteor showers only sporadic meteors this month

3 The highlights of the month. 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. Crescent Moon visibility. A 1.1% ultra thin crescent Moon is visible 20 min after sunset on February 12 th - Always ensure the Sun has set completely before sweeping for the crescent Moon low, close to the horizon Moonset is 17:52 hrs GMT A 4% waxing crescent Moon on February 13 th is better placed low in twilight evening skies for observing, setting at 19:07 GMT around an hour and half after sunset, binoculars show dimly lit features due to Earthshine. More detailed sky notes and LAS Newsletters are available to LAS members

4 Mar 3 Mars Mar 13 Feb 21 Feb 11 Mars Feb 1 Uranus Feb 1 Feb 11 Feb 21 Mar 3 Uranus Mar 13 Sky looking south at 8pm mid February 2021 Use the constellation of Orion to find other stars / constellations in the winter night sky Find the Dog Star (Sirius), the brightest star in the sky by following a line down through Orion s belt stars Almach Find `The Winter Triangle` asterism formed by stars Sirius, Procyon and Betelgeuse Find the red star Aldebaran and the Hyades star cluster in the constellation of Taurus by using Orion s belt stars. Menkib Use bright star Rigel and Betelgeuse to draw a line up to the bright stars Castor and Pollux in constellation Gemini Var Aldebaran Atik M45 Asterope Pleione Alcyone Atlas Taygeta Celaeno Electra Maia Merope Algol Aries Taurus Mirach M Cr Hamal +20 Sheratan +18 Mesartim +16 M N E Menkar + 2 4h 30m 4h 00m 3h 30m 3h 00m 2h 30m Alrescha 2h 00m 1h 30m Galaxy Open Cl Planetary Star? Circles are FOV (10x50 binoculars, showing Uranus is 1½ fields below Hamal (Aries) note also the motion of Mars as it moves eastward along the ecliptic from Aries into Taurus during February. 1 Beid 2 Keid 3 Azha

5 Sky looking west at 8pm mid February 2021 The Milky Way stretches from Cygnus in the NW through Cassiopeia and Perseus, good star fields can be seen with binoculars. The double cluster in Perseus is visible as a misty patch to the unaided eye on moonless evenings, but binoculars and telescopes show good views of these two star clusters visible in the same field of view at low magnification. The stars around Mirfak (in Perseus) known as the Mirfak Association of stars ( a moving star cluster). The star Algol (β Persei) is an unaided eye variable star ( a close eclipsing binary) that dips in brightness from +2.1m to 3.4m for 9.6 houtrs every 2.86 days, one such dip (minima) occurs at 20:10 UT on Feb 15 th.

6 Sky looking north at 8pm mid February 2021 Ursa Major (Plough asterism) stands on its tail. The two pointer stars Merek and Dubhe point to the pole star Polaris. Vega can be seen low on the northern horizon the star has a declination of +38 and so is` just` circumpolar i.e. never sets from latitude 51 N (Luton)

7 Sky looking east at 8pm mid February 2021 Use the pointer stars in the plough the wrong way to draw a line to the bright star Regulus and above it the `Sickle` asterism and the nice double star Algieba, a golden yellow and orange pair of stars visible in small telescopes. ( eg 60mm,x120 magnification ). About half way between the bright star Pollux in Gemini and Regulus in Leo you will find the misty patch of the Beehive star cluster, use binoculars to see this rich star cluster. Leo also has the famous Leo Triplet of edge on Galaxies M65 /M66 and NGC 3628 visible in moderate telescopes in moonless conditions. Detailed LAS Newsletter finder charts are available to LAS members.