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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.
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.
Mars
Mars despite fading this month from magnitude +0.5 to +0.9 remains a prominent evening object in Pisces. From mid-latitude northern temperature locations, it sets an hour or so before midnight, but slightly earlier for those located further south.
The angular diameter of Mars falls from 7.4 to 6.2 arc seconds as the month progresses, and therefore it's becoming difficult to spot surface details. On nights of good seeing, medium and large aperture backyard scopes at high powers may be able to tease out some of the larger features, such as the Syrtis Major.
On January 12th, the waxing crescent Moon passes 5 degrees south of Mars.
Mars and Uranus during January 2019 - pdf format (credit:- freestarcharts)
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.
Messier 45 - M45 - The Pleiades (Open Cluster)
M45, commonly known as the Pleiades or Seven Sisters, is the finest open cluster in the sky. It's a breathtaking site, known since antiquity and easily visible to the naked eye. Located in the large and prominent zodiac constellation of Taurus, this showpiece object is best seen during the Northern Hemisphere Winter and the Southern Hemisphere Summer months.
Finding M45 is easy. The cluster is positioned about 14 degrees northwest of orange giant star Aldebaran (mag. +0.9), the brightest star in Taurus. At first glance with the naked eye, it's obvious that something is special about this small section of sky. On closer inspection, M45 reveals itself to be a beautiful cluster of about half a dozen white stars, covering an area much greater than that of the full Moon. At the heart of the cluster is a set of stars that form a small dipper shape, similar to the brightest stars of Ursa Major. Even under light polluted skies the dipper shape is readily visible. From dark sites, the Pleiades is an outstanding naked eye object. The main stars appear bright and striking, with up to 10 or more visible under ideal conditions.
The Planets this Month - November 2018
Mercury
Mercury reaches greatest elongation east (GEE) on November 6th when it's 23 degrees in the sky from the Sun. From equatorial and southern locations, the inner planet can be found low down in the western evening sky early in the month just after sunset. It will set up to two hours after the Sun on the day of GEE and shine at magnitude -0.3. Each subsequent evening, the planet's visibility slightly decreases until it's eventually lost to the bright twilight. Mercury reaches inferior conjunction on November 27th.
From mid-latitude northern locations, the shallow angle of the ecliptic to the horizon means it will be a difficult low down target, best seen around GEE.
Venus
Venus returns to the morning sky this month. The brilliant planet is unmistakable before sunrise above the eastern horizon. As the month progresses it climbs higher in the sky, with its brightness increasing from magnitude -4.6 to -4.9 as the month progresses. Its angular size decreases from 60 to 41 arc seconds this month with its illuminated phase increasing from only 1% to 25%.
Mars
Mars is now an evening object. The 'Red planet' starts November in Capricornus before crossing into Aquarius on the 12th where it remains for the rest of November. Mars continues to fade with its magnitude decreasing from -0.6 to -0.1 as the month progresses. From southern locations, it appears high in the north-western sky after sunset. From northern locations, Mars can be seen in the southern sky and improves in elevation each subsequent evening.
Algol eclipse dates and times for November 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 35 - M35 - Open Cluster
M35 is a fantastic open cluster located in the constellation of Gemini. At magnitude +5.2, it's visible to the naked eye under good conditions. Curiously, despite being a naked eye object, it wasn't discovered until 1745-46 by Philippe Loys de Chéseaux and then independently "re-discovered" by John Bevis sometime before 1750. Since the cluster is reasonable close at 2,800 light-years it presents a large apparent diameter of some 28 arc minutes - almost exactly the same as that of the full Moon. Without a doubt, M35 is a magnificent sight in all types of optical instruments.
The constellation Gemini covers a reasonable 514 sq. degrees and is partially located in the rich star fields of the Milky Way. During the winter months, it's positioned high in the sky for Northern Hemisphere observers although less well placed for those located further south. Surprisingly, despite such a prime Milky Way location, M35 is the only Messier object in Gemini. It's located at the western edge of the constellation in a corner of the sky close to the Taurus, Orion and Auriga borders. Finding M35 is quite easy as it's 3.5 degrees northwest of mag. +2.9 star, Mu (μ) Gem.
