The Astronomical A-List:

                        50 of the best objects in the sky to observe with a small telescope.

 

Each entry gives the Messier or Caldwell number, the common name (if any) and the type of object.   Following this is a sequence of bold letters.  These indicate how the object may best be viewed:

E     The unaided eye

B     Binoculars

L     Telescope at low power

M    Telescope at medium powers

H     Telescope at high power.

The positions of the object are for equinox 2000.

 

 

Andromeda                                                                                                   

 

                        M31                The Andromeda Galaxy           Spiral galaxy         E B L

M31 is the nearest large galaxy to us at a distance of 2.9 million light years.  It is a spiral galaxy somewhat larger than out own, best seen with binoculars under very dark skies. It has an angular size of 160 x 40 arc minutes.  (0h 42.7m  +41o 16')

 

Auriga                                                                                   

 

                        M37                                                                Open cluster          B M

M37 is the largest and brightest of three open clusters in Auriga containing about 150 visible stars in a 25 arc minute field.    (5h 52.4m  +32o 33' )

 

Aquila

 

                                                Eta (h) Aquilae                        Cepheid variable  E B M

A bright Cepheid variable that varies in magnitude from 3.7 to 4.5  with a period of  7.2 days. It was the first Cepheid to be discovered, in 1784, and lies at a distance of about 1300 light years.  Such stars have enabled the distance scale of the universe to be determined.  (19h 52.5m  +01o 00')

 

 

Carina

 

                        C92                 Eta (h) Carina Nebula              Unstable star    B M

This extreme variable star  - it was one of the brightest stars in the sky in 1843 - is embedded in the Keyhole Nebula and is now at 7th magnitude.  It is thought to be a massive luminous star whose visible radiation is absorbed by the nebula and re-radiated in the infrared. It may soon become a supernova.  (10h 43.6m  -59 o 52')

 

 

 

 

Cancer

 

                        M44................ Beehive Cluster                       Open cluster   E B L

Sometimes called Praesepe, the manger, it appears as a misty spot to the eye under dark skies. It resembles a swarm of bees when viewed with a telescope under low power and contains over 350 stars at a distance of 577 light years.  (8h 40.1m  +19 o 59')

 

 

Canis Major

 

                        M41                                                                Open cluster  E B M

A lovely open cluster lying 4 degrees below Sirius with a beautiful orange-red star at its heart.   There are over 100 stars contained within it.  Aristotle observed it in 325 BC.

(6h 46.0m  -20 o  44')

                 

Canis Venatici

 

                        M51                Whirlpool Galaxy                     Interacting galaxies  M

A beautiful, face-on, spiral galaxy lying at a distance of 35 million light years.  Under dark skies the nuclei of  the two galaxies can be seen and, with larger telescopes, some hint of the spiral structure. (13h 29.9m  +47 o 12')

 

Centaurus

 

                                                Alpha (a) Centauri                   Double star           E H

Alpha Centauri is a double system whose separation varies from 2 to 22 arc seconds.  The primary star, magnitude -0.04, is similar to our Sun and the secondary is less massive and luminous with a magnitude of 1.2.  (14h 39.6m -60 o 50') 

 

                        C80                 Omega (v) Centauri                Globular cluster  E B M

The most spectacular globular cluster in the heavens, appearing as a 4th magnitude star to the unaided eye.  It contains over a million stars in a region about 159 light years across some 20,000 light years distant and has an apparent diameter of 30 minutes of arc.

(13h 26.8m  -47 o 29')

 

                        C77                 Centaurus A                             Active galaxy          E B M

A large, bright (7th magnitude), elliptical galaxy crossed by a wide dust lane, perhaps 15,000 million light years distant.  It is one of the most massive and luminous galaxies known.  It is a very strong radio source and harbours an ‘active galactic nucleus’ surrounding a supermassive black hole. (13h 25.5m -43o 01')

 

 

Crux

 

                                                Alpha (a) Crucis                      Double star                  E H

Two blue-white stars, 4.4 arc seconds apart, with a combined magnitude of 0.87.  A magnificent double star system discovered in 1685.  Both are B type stars several thousand times brighter than our Sun.  (12h 26.6 m  -63o 06')

 

                        C94                 Jewel Box                                Open cluster                   B L

Named by Sir John Herschel who called it "a gorgeous piece of fancy jewellery".  It contains over 50 highly luminous blue-white B type stars in a field of view 10 arc minutes across. There is a red supergiant star at its heart providing a magnificent colour contrast.  (12h 53.6m  -60o 21')

 

                        C99                 Coal Sack                                Dark nebula                    E B L

Just to the south of the Jewel Box is a pear shaped region of obscuring nebula 7 degrees long by 5 degrees wide called the Coal Sack. A dense region of dust and gas, it hides the light from more distant stars.  (12h 52m -63o 18' )

 

Cygnus

 

                        Beta (b) Cygni Albireo,            Double star                    E H

Perhaps the most beautiful double star system in the heavens. There is a superb colour contrast between the 3rd magnitude orange and 5th magnitude blue stellar components.  They are 34 arc seconds apart, so easily split in a small telescope. (19h 30.7m +27o 57')

 

                        C34                 The Veil Nebula                       Supernova Remnant       B L

A supernova remnant 2,000 light years away  that resulted from a supernova explosion 15,000 thousand years ago.   The easiest section to observe is the western section above and below the 4th magnitude star, 52 Cygni.  At magnitude 7, it should be visible under very clear and transparent skies with binoculars. (20h 56.0m  +31o 43')

 

Dorado

 

                        LMC               Large Magellanic Cloud           Irregular galaxy             E B L

An irregular (or possibly barred spiral) galaxy that, at about 166,000 light years distance, is one of the closest galaxies to our Milky Way galaxy.   It is at least 50,000 light years in diameter and contains several billion stars.  It is the fourth largest galaxy in our local group. To the eye it appears just like a cloud, hence its name.  The Large and Small Clouds (see Tucana) were first described by the Portuguese explorer Ferdinand Magellan in 1519. The LMC has an angular diameter of 6 degrees.   (5h 23.6m  -69 o 45')

 

                       

                        C103               Tarantula Nebula                      HII region and open cluster  B M

At the eastern end of the Large Magellanic Cloud is the Tarantula Nebula, a bright gaseous nebula over 2000 light years in diameter.  It is a massive region of star formation and the site of SN 1987A, the most recent supernova in our immediate neighbourhood.  At its heart is a compact star cluster called 30 Doradus that includes over 100 supergiant stars in a region just 100 light years across. (5h 38.6m  -69o 05')

 

 

Gemini

 

                        Alpha (a) Geminorum  Castor  Multiple star system        E H

A visual double with blue-white stars, A and B of  2nd and 3rd magnitudes respectively, separated by ~ 4 arc seconds.  A red dwarf star,  Castor C, orbits them both appearing about 1 arc minute away.  If fact, each of these stars is itself double, so the system contains 6 stars!  (7h 34.6m  +31o 53')

 

 

                        M35                                                                Open cluster                  E B L

This beautiful open cluster lies close to Castor's Foot.  It lies about 2,700 light years away and contains several hundred stars scattered over an area the size of the full Moon.  It is visible to the unaided eye under dark skies.  (6h 08.9m +24o 20')  Amateurs with larger telescopes may also spot a compact cluster, NGC 2158, just 15 arc minutes to the southwest.  (6h 07.5m  +24o 06')

 

                        C39                 Eskimo or Clown Nebula         Planetary nebula               H

A beautiful Planetary Nebula that has an unusually bright (10th magnitude) central white dwarf star.  A central bright region gives the face, and the star is his nose.  A larger, more diffuse, outer ring, seen only in larger telescopes, makes up the fur hood of the Eskimo's parka or the ruff of the clown's outfit.   (7h 29.2m +20o 55')

 

 

Hercules

 

                        M13                Hercules Cluster                       Globular cluster            E B M

This, the finest globular cluster in the northern sky, was discovered by Edmond Halley in 1714.  It contains probably over a million stars in a volume 145 light years across.  At  a distance of about 27,000 light years it has an angular extent of  20 arc minutes and, at magnitude 5.8, is just visible to the unaided eye in dark skies.   (16h 41.7m +36o 28')

 

                        M92                                                                Globular cluster               B  M

M92 is also a superb globular cluster, somewhat overshadowed by it near neighbour M13.  At a magnitude of 6.5 it is an easy object for binoculars or a small telescope.  It lies at about 26,000 light years and, with its angular extent of 14 arc minutes, corresponds to a diameter of 109 light years.  The total mass of stars in the cluster is  ~330,000 solar masses. (17h 17.1m +43o 08')

                       

 

Leo

 

                         M65/ M66                                                     Spiral galaxies                  L M

A pair of 9th magnitude spiral galaxies visible together at low power with a telescope or individually at medium powers.   M65 is a type Sa spiral which lies at a distance of 35 million light years and has a magnitude of 9.3. (11h 18.9m  +13o 05')  M66, considerably larger than M65, is a type Sb spiral at the same distance having a magnitude of 8.9.

 (11h 20.1m  +12o 59')

 

                        M95/ M96                                                      Spiral galaxies                  L M

M95 is a barred spiral of Hubble type SBb lying at a distance of 38 million light years having a magnitude of 9.7.  (10h 44.0m +11o 42')  M96 is a type Sa galaxy lying slightly further away at 41 million light years and is slightly brighter with a magnitude of 9.2. 

(10h 46.8m  +11o 49')  Both are members of the Leo I group of galaxies and are visible together with a telescope at low power.

 

 

 

 

Lyra

                                                Epsilon (e) Lyrae                     Twin double star system   E B H

Known as the double-double, this is perhaps the best multiple star system that can be easily observed.  Binoculars, and even perhaps the eye, will easily show that it is a double star with a separation of 3.5 arc minutes; but then, under good seeing conditions, a telescope at high power will show that each is itself a double star having separations of between 2 and 3 arc seconds.  The four stars range from 4.7 to 6.2 magnitudes. (18h 44.3m +39o 40')

 

                        M57                Ring Nebula                             Planetary nebula                   H

Perhaps the easiest to observe planetary nebula, the ring nebula looks like a smoke ring or doughnut.  With a magnitude of 8.8 the ring is easy to observe but, though visible on photographs, one will not observe the central white dwarf star, with a small telescope.

(18h 53.6m +33o 02')

 

Orion

 

                        M42                Orion Nebula                           Diffuse nebula          E B M H

One the most beautiful objects in the heavens!  This region of star formation is visible with the eye or binoculars as a diffuse glow in the sword of Orion. The use of medium powers with a telescope will show the looping whirls of dust and gas - perhaps with a slight greenish colour - illuminated by the light of the bright stars, called the trapezium, at its centre.  Higher powers will show the 4 individual blue-giant stars that make up the trapezium, whilst under very steady skies a fifth, fainter, star can be glimpsed too. (5h 35.4m  -5o 27')

                       

Pegasus

 

                        M15                                                                Globular Cluster     B M

A conspicuous globular cluster, magnitude 6.2, lying at a distance of 33,600 light years.  It appears about 7 arc minutes in diameter.  A small  telescope can resolve the outer stars.  (21h 30.0m  +12o 10')

 

                                                51 Pegasai                               Star with planet       E B

There is nothing to see here but a single star - so why look at it?  It was the first Sun-like star to have a planet discovered in orbit around it.  Surprisingly, the planet is a gas giant about half the mass of Jupiter that orbits its star every 4.2 days.  (22h 57.5m +20o 46')

 

 

Perseus

 

                        C14                 Double Cluster                         Twin Open Clusters  E B L M

Visible to the eye and binoculars as a hazy patch in the Milky way, a small telescope at low power can show these two beautiful clusters in the same field of view.  At a distance of about 7500 light years, each is about 50 arc minutes in diameter and they lie half a degree apart.  (2h 20.5m  +57o 08')

 

 

 

 

                        Algol                Beta (b) Persei                       Eclipsing Binary         E B

Known as the "demon star" as it winks!  It is an eclipsing binary system which drops in brightness from 2.1 to 3.4 and then rises again to 2.1 over a period of 10 hours once every 2.87 days.  (3h 8.2m  +40o 57')

 

Sagittarius

                       

                        M8                  Lagoon Nebula                       Diffuse nebula             B L

A bright region of nebulosity in the Milky Way, 90 x 40 arc minutes in extent.  Just visible to the eye under very dark skies it is very obvious in binoculars and seen well at low powers with a telescope. (18h 03.6m -24o 23')

 

                        M17                Swan Nebula                          Diffuse nebula         B M

Also called the Omega nebula, it is a wonderful sight in a telescope.  It contains enough gas, over 800 solar masses, to form a good sized star cluster in time.  It is at about 5500 light years distant and extends over an angular extent of 11 arc minutes. (18h 20.8m  -16o 11')

 

 

                        M20                Triffid Nebula  Diffuse nebula         B M

So called because of its three lobed appearance, the trifid nebula was discovered by Charles Messier in 1764.  A glowing  region of gas 28 arc minutes in diameter with a small star cluster at its heart.  (18h 02.6m  -23o 02')

 

Scorpius

                       

                        M6                  The Butterfly Cluster                Open cluster              B L

The cluster, at a distance of about 2000 light years contains around 80 stars in a butterfly shape. Four of the brightest stars form a nice parallelogram; the lower left being an orange giant which contrasts beautifully with the other three blue-white stars.

(17h 40.1m -32o 13')

 

                        M7                  Ptolemy’s Cluster                     Open cluster             E B L

A wonderful cluster, visible to the unaided eye and easily seen with binoculars.  It contains 80 stars brighter than 10th magnitude in a field just over 1 degree across.  Superb when seen through a telescope at low power.  It lies at a distance of around 1000 light years. (17h 53.9m -34o 49')

 

                        C76                 Scorpius Jewel Box                  Twin open clusters    E B L

                                                ( NGC 6231 / TR24 )

A most beautiful region in the Milky Way which contains several clusters and regions of nebulosity.  NGC 6231, also called the Northern or Scorpius Jewel Box, is the richest and most compact of these.  Just visible to the unaided eye, it is wonderful to observe with a low power telescope. (16h 54.2m -41o 50')         

 

 

 

 

 

Taurus

 

                        M45                Pleiades Cluster                       Open cluster   E B L

Perhaps the most beautiful cluster in the heavens, it is often called the Seven Sisters.  Most people can actually see 6 stars with their unaided eyes, some 9.  It contains at least 500 members and is only 380 light years away.  It is a beautiful sight with binoculars or when using a telescope at low power with a wide field eyepiece as the stars are spread over a region 2 degrees across.  (03h 47.0m +24o 07')

 

                        C41                 Hyades Cluster Open cluster                  E B

This famous V-shaped cluster outlines the head of the bull with Aldebaran his eye - although Aldebaran is not part of the cluster and lies at only half its distance.  The cluster contains about 200 stars and lies at a distance of 150 light years.  Best seen with binoculars, as its angular extent is several degrees. (04h 26.9m +15o 52')

 

 

                        M1                  Crab Nebula                            Supernova remnant          M

Not over impressive to observe - a smudge of light - needing a dark sky to see.  It is, though, the most recent supernova remnant that can be observed with a small telescope. The supernova was observed by Chinese astronomers in AD 1054 and its remnant, the Crab Nebula, was discovered by John Bevis in 1731.  At its heart is the collapsed core of the original star spinning on its axis 30 times a second; a pulsar whose beams sweep around the sky like an interstellar lighthouse. (05h 34.5m +22o 01')

 

 

Triangulum

 

                        M33                Galaxy in Triangulum                Spiral galaxy               B L

A face-on type Sc spiral, about 3 million light years away and the third largest galaxy in our local group.  It requires a very dark and transparent night to observe.  In binoculars, it looks like a little square of tissue paper stuck on the sky.  Larger aperture telescopes may show the open spiral arms. (01h 33.9m  +30o 39')

 

Tucana

 

                        SMC               Small Magellanic Cloud            Irregular galaxy     E B L

A small companion to our own galaxy, it lies at a distance of 210,000 light years and covers an angular extent of  280 x160 arc minutes.  Easily visible to the unaided eye under dark skies, binoculars and telescopes at low power show it well.

(00h 52.7m -72o 50')

 

                        C106               47 Tucanae                              Globular cluster     E B M

Close to the SMC, this is the second largest and second brightest globular cluster in the sky. With a brightness of 4.2 magnitudes it is easily seen with the unaided eye under dark skies, its stars covering an area about the size of the full moon. (00h 24.1m -72o 05')

 

 

Ursa Major

 

                        M81/M82                                                       Spiral and irregular galaxies   B L M

M81 is a type Sb spiral with a magnitude of 6.9. (09h 55.6m +69o 04')  It forms a wonderful pair, seen at low power in a telescope, with the irregular, 8.4 magnitude, galaxy M82. (09h 55.8m +69o 41') They both lie at a distance of 12 million light years. 

 

 

                        Zeta (z) and 80     Mizar and Alcor       Visual and telescope doubles       E B H

                        Ursae Majoris

The unaided eye can just make out the Mizar/Alcor (horse and rider) optical double, and it is easy with binoculars.  A telescope will show that Mizar is also a double star, its blue stars separated by 14 arc seconds. A third fainter red star makes a nice triangle with Mizar and Alcor. (13h 23.9m  +54o 55')

 

                       

Virgo

                        M87                                                                Active galaxy                       M

An 8.6 magnitude giant elliptical galaxy at the heart of the Virgo Cluster.  It is 7 arc minutes in angular extent and lies at a distance of 60 million light years.  It contains several trillion stars. (12h 30.8m +12o 24')

 

                        M104              Sombrero Galaxy                     Edge on spiral galaxy          M

This is a type Sa spiral galaxy with a very prominent nucleus crossed by the dark dust lanes of its tightly wound spiral arms. It is 8th magnitude and lies at a distance of  50 million light years. (12h 40.0 -11o 37')

 

                        Gamma (g) Virginis      Porrima                        Double Star                       E H

A prominent star in Virgo, it is actually composed of two F type stars about 7 times brighter than our Sun.  They are in a highly elliptical orbit with a period of 171 years.  Their next closest approach to each other is in 2007 and, around this time, they will be difficult to split into two. (12h 41.7m -1o 27') 

 

Vulpecula

 

                        M27                Dumbell Nebula                       Planetary nebula              B M

An object of magnitude 7.4, one of the most impressive to view of its kind, which has an angular extent of 8x6 arc minutes. Under dark skies it shows up well in 10x50 binoculars and also using telescopes at moderate powers. (19h 69.6m +22o 43')

 

                                                Brocchi’s Cluster                     Asterism/ open cluster         B L

This cluster of about 40 stars, about 1 degree across in the sky, is also called the "Coat-hanger" as its 10 brightest stars make up the shape if an upside down coat-hanger.  It stands out well against the dark Cygnus rift along the Milky Way. (19h 25.4m +20o 11')