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Messier 67 - M67 - Open Cluster
Messier 67 is a very old open cluster located in the constellation of Cancer. Estimations of its age vary between 3.2 and 5 billion years, with recent valuations putting it at 4 billion. This makes it one of the oldest known open clusters. As a consequence, M67 contains a variety of stellar types including many Sun like stars, red giants and white dwarfs. It's easily the most ancient Messier open cluster. For comparison, the Praesepe (M44) is 600 million years old and the brilliant Pleiades (M45) a very youthful 100 million years.
The constellation of Cancer is a faint zodiac constellation that's bordered by much brighter Leo to the east and Gemini to the west. To the north lies Lynx, with Canis Minor and Hydra positioned on the southern side. To find M67, first locate stars Asellus Australis (δ Cnc - mag. +3.9), Asellus Borealis (γ Cnc - mag. +4.7), η Cnc (mag. +5.3) and θ Cnc (mag. +5.3). This quadrangle forms the main part of the constellation and located at its centre is M44. Next focus on another faint star, α Cnc (mag. +4.3), which is positioned 9 degrees further to the southeast. M67 is positioned 1.75 degrees west of this star.
M67 was discovered sometime before 1779 by German astronomer Johann Gottfried Koehler. He described it as being rather conspicuous and nebula like, although with his basic telescope he was unable to resolve any stars. Charles Messier then independently rediscovered M67, resolved it into stars and catalogued it on April 6, 1780. He noted it as a "cluster of small stars with nebulosity, below the southern claw of Cancer. The position determined from the star Alpha [Cancri].".
M67 is best seen from the Northern Hemisphere during the months of February, March and April.
Messier 44 - M44 - The Praesepe (Open Cluster)
M44, also known as the Praesepe or Beehive cluster, is a sprawling open cluster. It's the brightest and most prominent deep sky object in the constellation of Cancer. Visible to the naked eye under dark skies, the cluster appears like a large misty cloud covering over 1.5 degrees of sky. The brightness and size of M44 results from its close proximity to Earth; it lies a mere 577 light-years distant. Only the Hyades (at 153 light-years), Coma cluster (280 light-years), the Pleiades (M45) (425 light-years), Southern Pleiades (480 light-years) and IC 2391 (500 light-years) are nearer. Consequently, M44 is one of the brightest and largest objects of its type in the night sky.
The constellation of Cancer is a faint zodiac constellation that's bordered by much brighter Leo to the east and Gemini to the west. To the north is faint Lynx, with Canis Minor and Hydra located on the southern side. At the heart of Cancer is a grouping of four faint stars. They are Asellus Australis (δ Cnc - mag. +3.9), Asellus Borealis (γ Cnc - mag. +4.7), η Cnc (mag. +5.3) and θ Cnc (mag. +5.3). Of these, the brighter two are relatively easy naked eye objects, the fainter ones more difficult. Positioned at the centre of this grouping is M44. An alternative method of locating M44 is to imagine a line extending in a southeastern direction from Pollux (β Gem - mag. +1.1) for 37 degrees to Regulus (α Leo - mag. +1.4). M44 is positioned approximately at the mid-point of this line.
Nearly 2,000 years ago, the astronomer Ptolemy described M44 as "the nebulous mass in the breast of Cancer". It was Galileo who first telescopically observed the Praesepe. He did this in 1609 and was able to resolve 40 stars. Charles Messier added the item to his catalogue on March 4, 1769.
M44 is best seen from the northern locations during February, March and April.
The Planets this Month - February 2019
Mercury
Mercury passed through superior conjunction (on the far side of the Sun) at the end of last month. From mid-latitude northern locations, the fast-moving planet will become visible low down in evening twilight towards the end of the second week of the month. Mercury then climbs higher each subsequent evening until greatest elongation east (GEE) is reached on February 27th. On this day, the planet will be positioned 18 east degrees of the Sun. From mid-latitude northern locations, it shines at magnitude -0.5 and appears 9 degrees above the western horizon 45 minutes after sunset.
From southern latitudes, due to the angle of the ecliptic, Mercury will be difficult to spot in evening twilight this month. Even at GEE it sets only forty minutes later than the Sun.
Venus
Venus remains a brilliant early morning star throughout February. Although, the planet dims from magnitude -4.3 to -4.1 as the month progresses it's easily brighter than any other planet or night-time star. At the same time, its illuminated phase increases from 62% to 72%. On February 18th, Venus passes a degree north of Saturn (mag. +0.6). At months end, Venus rises a couple of hours before the Sun.
Mars
Mars continues as evening object this month. However, it's now well past its best and as the month progresses fades from magnitude +0.9 to +1.2. Its angular size falls to about 5 arc seconds and therefore it's no longer possible to spot details on its pink surface. The waxing crescent Moon passes 6 degrees south of Mars on February 10th. On February 12th, Mars crosses the constellation border into Aries from Pisces. A day later it passes a degree north of much fainter Uranus (mag. +5.8). From northern locations Mars sets 5 hours after the Sun, although up to a couple of hours less for those located further south.
Mars and Uranus during February 2019 - pdf format (credit:- freestarcharts)
Algol eclipse dates and times for February 2019
Algol (β Per) is a bright eclipsing binary system located in the northern constellation of Perseus and one of the best-known variable stars in the sky. Often referred to as the "Demon Star", most of the time it shines at mag. +2.1 but every two days, 20 hours and 49 minutes it suddenly dips in brightness to mag. +3.4, remaining dim for about 10 hours before returning to its original state.
Why the brightness change. The Algol system consists of at least three-stars (β Per A, β Per B and β Per C) with the orbital plane of Algol A and B directly in line with the Earth. The regular dips in brightness occur when the dimmer B star moves in front of and eclipses the brighter A star. There is also an extra dimension in that a secondary eclipse occurs when the brighter star occults the fainter secondary, resulting in a very small dip in brightness that can be detected with photo-electrical equipment.
Algol is located in Perseus among the stars of the northern Milky Way. It's positioned west of mag. +0.1 Capella (α Aur) and southeast of the well known "W" of Cassiopeia. The finder chart below shows the position of Algol along with magnitude data of some surrounding stars for comparative purposes.
Finder Chart for Algol - pdf format (credit:- freestarcharts.com)
Messier 78 - M78 - Reflection Nebula
M78 is an often forgotten nebula in the constellation of Orion. It's a reflection nebula that's part of the Orion Molecular Cloud Complex, a large cloud of gas and dust centered on the famous Orion Nebula (M42) and De Mairan's Nebula (M43). Also included in this grouping are NGC 2064, NGC 2067 and NGC 2071 and other nebulae. Reflection nebulae like M78 are clouds of interstellar dust that shine due to reflected and scattered light from nearby stars.
M78 was discovered by Pierre Méchain in early 1780 with Charles Messier adding it to his catalogue on December 17, 1780. Although only of 8th magnitude, finding M78 is easy since it's positioned just a few degrees northeast of Orion's famous belt. The three bright stars that make up the belt are Alnitak (ζ Ori - mag. +1.72), Alnilam (ε Ori - mag. +1.69) and Mintaka (δ Ori - mag. +2.25). Positioned 2.5 degrees northeast of Alnitak is M78.
Algol eclipse dates and times for January 2019
Algol (β Per) is a bright eclipsing binary system located in the northern constellation of Perseus and one of the best-known variable stars in the sky. Often referred to as the "Demon Star", most of the time it shines at mag. +2.1 but every two days, 20 hours and 49 minutes it suddenly dips in brightness to mag. +3.4, remaining dim for about 10 hours before returning to its original state.
Why the brightness change. The Algol system consists of at least three-stars (β Per A, β Per B and β Per C) with the orbital plane of Algol A and B directly in line with the Earth. The regular dips in brightness occur when the dimmer B star moves in front of and eclipses the brighter A star. There is also an extra dimension in that a secondary eclipse occurs when the brighter star occults the fainter secondary, resulting in a very small dip in brightness that can be detected with photo-electrical equipment.
Algol is located in Perseus among the stars of the northern Milky Way. It's positioned west of mag. +0.1 Capella (α Aur) and southeast of the well known "W" of Cassiopeia. The finder chart below shows the position of Algol along with magnitude data of some surrounding stars for comparative purposes.
Finder Chart for Algol - pdf format (credit:- freestarcharts.com)
Planets this Month - January 2019
Mercury
Mercury is now heading towards superior conjunction, which it reaches on January 29th. However, observers may still be able to spot the elusive planet low down in the early morning twilight during the early part of the month. On January 1st, it shines at magnitude -0.4.
Venus
Venus reaches greatest elongation west on January 6th, when it's positioned 47 degrees from the Sun. On this day, the brightest planet will rise some 3 hours before the Sun, shining at a dazzling magnitude -4.6. Venus remains a spectacular object throughout January, although it fades slightly to magnitude -4.3 by month's end. During this time its angular size decreases from 26 to 19 arc seconds, with its illuminated disk increasing from 47% to 62%.
On New Year's Day, the thin waning crescent Moon passes less than two degrees north of Venus. The Moon again passes just north of Venus on the last day of the month, although on this occasion the separation is just 0.1 degrees. For a couple of days either side of January 22nd, Venus and Jupiter (mag. -1.9) will only be a few degrees apart.
Algol eclipse dates and times for December 2018
Algol (β Per) is a bright eclipsing binary system located in the northern constellation of Perseus and one of the best-known variable stars in the sky. Often referred to as the "Demon Star", most of the time it shines at mag. +2.1 but every two days, 20 hours and 49 minutes it suddenly dips in brightness to mag. +3.4, remaining dim for about 10 hours before returning to its original state.
Why the brightness change. The Algol system consists of at least three-stars (β Per A, β Per B and β Per C) with the orbital plane of Algol A and B directly in line with the Earth. The regular dips in brightness occur when the dimmer B star moves in front of and eclipses the brighter A star. There is also an extra dimension in that a secondary eclipse occurs when the brighter star occults the fainter secondary, resulting in a very small dip in brightness that can be detected with photo-electrical equipment.
Messier 42 - M42 - The Great Orion Nebula (Emission/Reflection)
M42, also known as the Great Orion Nebula or Orion Nebula, is the prime deep sky attraction in the constellation of Orion and a showpiece deep sky object. With an apparent magnitude of +4.0, it's easily visible to the naked eye. This emission / reflection nebula and star forming region spans more than a degree of sky and is therefore one of the largest and brightest objects of its type.
Orion is a prominent constellation and one of the most recognizable and familiar sights. Located on the celestial equator, it's visible throughout the World and best seen during the months of December, January and February. The constellation is filled with bright stars, including first magnitude Rigel and Betelgeuse plus a further five second magnitude stars. Three of the second magnitude stars (Mintaka, Alnilam and Alnitak) form the famous belt of Orion. Positioned just 5 degrees south of the belt is the Orion Nebula itself, which is part of the Hunters Sword.
