Guides / Star Charts
Shop at Amazon
Contributions
If you like the website and want to contribute to the running costs then please do so below. All contributions are most welcome.
NGC 3626 - Spiral Galaxy
NGC 3626, mag. +10.9, is a spiral galaxy in Leo that was discovered by William Herschel on March 14, 1784. It's one of many galaxies in the constellation within the range of small scopes.
NGC 3626 is located 70 million light-years away. It covers 2.7 x 1.9 arc minutes of apparent sky, which corresponds to a spatial diameter of 55,000 light-years and is estimated to contain 40 billion stars.
Patrick Moore listed, NGC 3626, as number 40 in his Caldwell catalogue. It belongs to the NGC 3607 group of galaxies.
Messier 65 - M65 - Spiral Galaxy
M65 is a magnitude +9.6 edge-on spiral galaxy located 35 million light-years distant. It was discovered by Charles Messier on March 1, 1780, the night he also discovered M66. Messier described the galaxy as "a very faint nebula without stars." Apart from M81 and M82 in Ursa Major, M65 and M66 are probably the most sought after galaxy pair for amateur astronomers. With a third galaxy, NGC 3628, lying nearby the trio forms the heart of a small celebrated group, known as the Leo Triplet or M66 group. All can be observed or photographed in the same field of view and are a popular target for observers and astrophotographers alike.
M65 is located in the eastern section of the relatively large and bright zodiac constellation of Leo, the Lion. In western skylore, the Lion's heart is marked by the constellation's brightest and only first magnitude star, Regulus (α Leo - mag +1.4). Positioned approximately 16 degrees northeast of Regulus is Chertan (θ Leo - mag. +3.3). Along with the Zosma (δ Leo - mag. +2.6) and Denebola (β Leo - mag. +2.1), Chertan forms a prominent right-angled triangle. Located 2 degrees south of Chertan is 73 Leonis (mag. +5.3). M65 lies 0.75 degrees east of this star, with M66 a further 0.33 degrees to the southeast of M65. Positioned 0.5 degrees north of the Messier pair is the third member of the triplet, NGC 3628.
The galaxies are best seen during the months of March, April and May.
Messier 66 - M66 - Intermediate Spiral Galaxy
M66 is a superb bright intermediate spiral galaxy located in the constellation of Leo. It's the brightest of a trio of galaxies that forms - along with M65 and NGC 3628 - the well known and popular Leo Triplet or M66 group. All three objects can be observed with small telescopes in the same low power field of view. After the M81/M82 pair in Ursa Major, the Leo Triplet is arguably the next most sought after galaxy grouping for amateur astronomers.
Charles Messier discovered both M66 (mag. +8.9) and M65 (mag. +9.6) on March 1, 1780. The apparent magnitude of the third member of the triplet, NGC 3628, is unclear. Some texts record it as the brightest group member, while others have it as the faintest. For our purposes we estimate NGC 3628 to be brighter than M65 and almost as bright as M66. However, what is clear is that it suffers from a low surface brightness and therefore is the most difficult member of the trio to spot. Messier missed it completely and it was not until April 8, 1784 when it was finally discovered by William Herschel.
To find the triplet, look to the eastern part of Leo. This zodiac constellation is relatively large and bright and somewhat looks like the Lion that it's supposed to represent. The brightest star in Leo and its only first magnitude star is Regulus (α Leo – mag +1.4). Positioned approximately 16 degrees northeast of Regulus is Chertan (θ Leo - mag. +3.3). Along with the Zosma (δ Leo - mag. +2.6) to the north and Denebola (β Leo - mag. +2.1) to the east, Chertan forms a prominent right-angled triangle. Located 2 degrees south of Chertan is 73 Leonis (mag. +5.3). M65 lies 0.75 degrees east of this star with M66 a further 0.33 degrees southeast of M65. NGC 3628 is positioned 0.5 degrees north of the Messier pair.
The galaxies are best seen during the months of March, April and May.
Finder Chart for M66 - pdf format (credit:- freestarcharts)
Messier 32 - M32 - Dwarf Elliptical Galaxy
M32 is a dwarf elliptical galaxy located in the constellation of Andromeda. It's a satellite of the famous and much larger Andromeda Galaxy (M31) and was the first elliptical galaxy ever observed. M32 was discovered by French astronomer Guillaume Joseph Hyacinthe Jean-Baptiste Le Gentil de la Galaisière (usually referred to as Guillaume Le Gentil) on October 29, 1749. Le Gentil, who was born in Coutances, Normandy, also discovered the Lagoon Nebula (M8) and was the first to catalogue the dark nebula Le Gentil 3 in Cygnus. He also independently found M36 and M38, objects that were discovered by Giovanni Batista Hodierna, around 100 years previously.
At a distance of about 2.65 million light-years, M32 is 110,000 light-years further from us than M31. Like most elliptical galaxies it contains mostly old red and yellow stars with practically no dust or gas, implying no current star formation. However, it has shown hints of star formation in the relatively recent past.
Locating M32 is as easy as locating the Andromeda Galaxy, which is positioned northeast of the Great Square of Pegasus. Of the four stars of the square, only three of them actually belong to Pegasus. The northeastern star and brightest of the four, Alpheratz (α And - mag. +2.1) is part of neighbouring Andromeda. Located 7 degrees northeast of Alpheratz is δ And (mag. +3.3) and a further 8 degrees northeast is Mirach (β And - mag. +2.1). The Andromeda galaxy is 8 degrees northwest of Mirach, at the end of a line connecting Mirach with μ And and ν And. M32 is located 22 arc minutes south of the central region of M31 and appears to be superimposed on a spiral arm.
The galaxy is best seen from Northern Hemisphere latitudes during the months of October, November and December.
Messier 31 - M31 - Andromeda Galaxy (Spiral Galaxy)
M31, the famous Andromeda Galaxy, is the largest member of the Local Group that also includes the Milky Way, the Triangulum Galaxy (M33) and about 50 other smaller galaxies. With an apparent mag. of +3.4, it's one of the brightest Messier objects and easily visible to the naked eye even from areas with a certain amount of light pollution. M31 is usually regarded as the most distant object that can be easily seen without optical aid.
The Andromeda Galaxy has been known for a long time. It was first recorded over 1000 years ago by Isfahan based Persian astronomer Abd-al-Rahman Al-Sufi. In 964 AD, he described it as the little cloud in his Book of Fixed Stars. This object was almost certainly known - for a number of years before this date - to other Persian astronomers. The first person to telescopically observe and describe M31, was German astronomer Simon Marius on December 15, 1612. Unaware of both Al Sufi's and Marius' discovery, Giovanni Batista Hodierna independently rediscovered the object sometime before 1654. Then on August 3, 1764, Charles Messier added the great spiral to his catalogue. Incidentally, Messier incorrectly credited Marius as the discoverer, apparently unaware of the earlier work of Al-Sufi.
Ursa Major - Constellation Guide
Ursa Major
Ursa Majoris
UMa
The Great Bear
Introduction
Ursa Major or the Great Bear is a prominent constellation in the northern celestial hemisphere. It's the third largest constellation in the sky and contains a central feature of seven stars, known as the Plough or Big Dipper, which is one of the most recognisable patterns. It's made up of stars, Dubhe, Merak, Phecda, Megrez, Alioth, Mizar and Alkaid. Ursa Major was listed by Ptolemy as one his 48 constellations in his second century Almagest and remains today as one of the modern 88 constellations.
The constellation spans a vast swath of the northern sky, covering almost 1,280 square degrees in surface area. Of course, the Plough is its standout feature, which has been referenced in drawings and writings since the dawn of civilisation. In Europe, the pattern symbolised a wagon or chariot that was associated with King Arthur. In Roman mythology, Jupiter the King of the God's, lusted after a beautiful woman named Callisto who was transformed into a bear by his jealous wife, Juno. Arcas the son of Callisto almost shoots the bear, but to avoid tragedy, Jupiter turns Arcas also into a bear, placing them both in the sky as Ursa Major and Ursa Minor. The Arabs viewed the grouping as a coffin and Ursa Major, along with Orion and the Pleiades, are mentioned in the Bible.
Most of the stars of the Plough belong to a nearby stellar group, known as the Ursa Major Moving Group or Collinder 285. All member stars are moving in roughly the same direction and at about 80 light-years distant it's the nearest cluster like object to Earth. Of the seven stars, only Dubhe and Alkaid are not actual group members.
The Plough asterism is a very useful guide for locating other stars. Two stars in the bowl Dubhe and Merak act as a pointer to Polaris, the Pole star. An imaginary line extending from Megrez through Dubhe and onwards leads to first magnitude Capella. The handle of the Plough points towards the brightest star in the northern section of the sky Arcturus.
Ursa Major is circumpolar from many Northern Hemisphere locations and is best seen during the months of March, April and May.
Ursa Major Star Chart - pdf format (credit:- freestarcharts)
Algol eclipse dates and times for April 2020
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 eclipse dates and times for March 2020
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 eclipse dates and times for February 2020
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.