The Binocular Astronomer in Autumn

Dark Skies of Tomintoul and Glenlivet

1. – An Ancient in

At 13 billion old, Messier 5 is one of the oldest globular clusters in the . It can be found low in the sky to the west of Serpens Caput. If you imagine an equilateral triangle pointing west with two corners at Epsilon and Mu Serpens then M5 is at the other corner of the triangle on the Globular Clusters western side. M5 is one of the largest known globular clusters. According to some estimates it may contain as many as 500,000 . Globular clusters are balls of stars that orbit the centres of major 2. The Great Cluster in Hercules () . These clusters are tightly bound together by gravitational Messier 13 is probably the best known globular cluster in the Messier list. It can be found on the attraction. Around 150 globular Bootes side of the Keystone in Hercules, about two thirds of the way from Zeta Herc to Eta Herc. clusters are known to exist around M13 contains around 300,000 stars and is about 145 light years in diameter at a distance of 25,000 the Milky Way, each one of them light years from . containing several hundred thousand stars. They are all 3. The Summer (IC4665) extremely ancient and are thought to be the remnant cores of galaxies A fine binocular cluster that is almost twice the diameter of the full . It can be found in the that have been assimilated by the of , about one degree north east of Beta Ophiuchi in the same binocular field th th Milky Way. Globular clusters as the itself. The cluster consists of around a dozen 7 to 8 magnitude stars. It is less than 40 usually appear as a fuzzy star million years old and lies about 1,400 light years from Earth. through . A telescope is needed to see any individual stars 4. – A Globular Cluster in Ophiuchus in the cluster. Woolly mammoth were still grazing the tundra when the light from Messier 10 started it's journey to your eyes! This cluster can be found just over two binocular fields in the direction of Aquila. M10 is estimated to be 11.4 billion years old and 14,300 light years away from Earth. 5. – An Ancient Globular Cluster in Ophiuchus Planetary Nebulae

At 12.7 billion years old, Messier 12 is 92% as old as the universe itself! You should be able to find A planetary consists of an it in the same binocular field as M10 above, a little to the north west. It is located about 15,700 light expanding shell of gas ejected years from Earth. from an old star late in it's life. They are relatively short- 6. Epsilon Lyrae – A Binary lived, lasting only a few tens of thousands of years, compared to a Epsilon Lyrae is a double . You should be able to find it in the same binocular field as typical stellar lifetime of several . Lying at a distance of around 162 light years from Earth, the two stars take hundreds of billion years. They are called thousands of years to orbit each other. A telescope, with more magnification, will reveal that each planetary nebulae because William star is a double itself. In fact this system is now thought to contain as many as ten stars. Herschel thought that they resembled planets when viewed 7. The (Messier 57) through his telescope in the 1780's. The name has stuck One of the most famous objects in the night sky, Messier 57 is a classic . It can be although it is misleading. The found about halfway between Beta and . Whilst M57 is easily visible in binoculars you central star ends up as a white might well miss it. Because the ring is only 80 arc seconds across it will appear as a faint, slightly dwarf after losing most of it's out of focus star. A telescope is needed to see the ring itself. material to the nebula.

8. Alya – A Close

A challenging double star for binoculars. Alya () is the last bright star (magnitude 4.6) in the tail of Serpens. Close examination will reveal that it is a double star. You will need to hold your binoculars very steady or mount them on a tripod for this one! Both stars are quite similar to one another and have an of at least 14,000 years.

9. Graff's Cluster (IC4756)

This big showy can be found about one binocular field west of Theta Serpentis. It is about 1,300 light years away from earth and has around 80 members stars. 10. Barnard's “E” - A in Aquila Double Stars

A mysterious dark “E” can be found silhouetted against the faint background glow of the Milky Way A double star is a pair of stars that in Aquila on clear moonless nights. Barnard's “E” is about half a binocular field to the north west of appear close to each other in the Altair. It is named after Edward Barnard (1857 - 1923) who compiled a list of dark markings in the sky. This is either because two sky. stars at different distances are aligned by chance (an optical 11. – A Globular Cluster in double), or because the two stars are orbiting one another (a binary There are not many that will fit into a binocular field of view, but Sagitta (The Arrow) double). A binary star system is one of them. Look carefully along the shaft of the arrow. Halfway between Gamma and Delta you whose orbit is edge on to our line should spot the globular cluster M71. It is relatively close to us for a globular, lying only 12,000 light of sight is called an eclipsing years away. It is also one of the youngest globular clusters at around 9 – 10 billion years old. double star. The best known example is Algol – the Demon 12. The (Messier 27) Star.

The Dumbbell Nebula is the biggest and brightest planetary nebula in the Messier catalogue. It lies around half a binocular field north of Gamma Sagittae. It will appear as a small disk just below the Dark Nebulae central star of a distinctive “M” shaped . The Dumbbell Nebula is about 1,360 light years away and has a diameter of around 3 light years. A dark nebula is a cold cloud of interstellar gas and dust, so dense 13. The Coathanger (Brocchi's Cluster) that it obscures the light from the stars behind it. These dark clouds The Coathanger is an unmistakable asterism despite being upside down! Find it about one binocular are where new stars are born. field to the north west of Alpha Sagittae. Although it's stars appear to be close together, they are a chance alignment at very different distances from us.

14. – A Globular Cluster in Aquarius

At 13 billion years old and a diameter of 175 light years, Messier 2 is one of the oldest and largest globular clusters in the Milky Way. It is about one binocular field north of Beta Aquarii. Lying at a distance of 37,500 light years from Earth, it contains around 150,000 stars.

15. The Great Cluster ()

M15 is one of the most densely packed globular clusters in the Milky Way. First find the Great Square of Pegasus. Now look for to the west of the square. Finally move one binocular field towards Cygnus to find M15. It has over 100,000 stars within it's 175 light years diameter. Asterisms 16. The Engagement Ring Asterisms are obvious groupings The Engagement Ring is one of the prettier asterisms. It can be found in the constellation of Ursa of stars that are not one of the Minor (The Little Bear). The ring is a rough circle of 8th and 9th magnitude stars opposite the body of traditional constellations. The eye Ursa Minor. itself is the sparkling diamond in the ring. It is visible all night long and all and brain are excellent at seeing round from our latitude. meaningful patterns in random collections of stars. 17. Omicron Cygni – A Triple Star

A colourful triple star system. Omicron Cygni is about one binocular field to the west of (Alpha Cygni), the top left star of the . It consists of a golden magnitude 3.8 star widely separated from a bluish – white companion at magnitude 4.8. These two are an optical double. However almost lost in the glow of the magnitude 3.8 star is a third magnitude 7.0 star. This is an eclipsing binary pair with an orbital period of around 10 years.

18. – An Open Cluster

The light from Messier 39 started it's journey towards Earth at around the time of the Norman Conquest! M39 can be found about two binocular field widths to the north east of Deneb (Alpha Cygni). It has about 30 member stars and is 200 – 300 million years old.

19. Barnard 168 – A Dark Nebula

A finger of darkness against the background stars of the Milky Way. From M39 move half a binocular field to the east to find it. This is B168, a dark nebula of 2,500 solar that is about 500 light years away from Earth. 20. Caldwell 16 (NGC7243) – An Open Cluster in Lacerta Galaxies

Caldwell 16 was born when dinosaurs ruled the earth around a hundred million years ago. First of A is a collection of stars, all find the constellation of Lacerta that lies halfway between Cygnus and Cassiopeia. From Alpha interstellar gas and dust bound Lacertae. move about half a binocular field towards Deneb to find Caldwell 16. C16 is around 2,800 together by gravity. The Milky light years away from Earth. Way is our home galaxy. Galaxies range in size from dwarfs with just 21. NGC6939 – An Ancient Open Cluster in a few billion stars to giants with a hundred trillion stars, each NGC6939 is one of the oldest open clusters in the Milky Way at around 1.2 billion years old. It can orbiting its galaxy's centre. Many be found just over one binocular field west of just beyond . It is around galaxies are thought to have black 3,800 light years away. holes at their centres. Galaxies also come in a variety of shapes: 22. The Fireworks Galaxy (Caldwell 12, NGC6946) elliptical spiral and irregular. The majority of galaxies are organized The Fireworks galaxy is a starburst galaxy – so called because it has a far higher rate of star into groups by gravity. formation than most other galaxies. It can be found in the same binocular field as NGC6939, just to the south east. Although visually almost next door, it is over 5,000 times as far away as NGC6939 at around 22 million light years. Nine supernovae have been observed in it over the past century. Stars

23. Herschel's Garnet Star ( ) Most carbon stars are red giants whose atmosphere contains more Herschel's Garnet star is one of the reddest carbon stars north of the . It lies just over a carbon than . The oxygen binocular field width south of Alpha Cephei. Herschel's Garnet Star is a red supergiant. If it were at combines with the carbon in the the centre of the solar system it's outer atmosphere would extend past Jupiter! upper layers of the star. Left over carbon atoms form other compounds, giving the star a striking red appearance.