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Object list indexed by constellation Part One A - Co


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This is a guide to what is visible in what constellation, the following is a combination of notes from myself and Richard Dibson-Smith who I would like to thank for letting me use them . All these objects are capable of being seen with instrutments up to 12" from a dark site.


Best viewed in EMS Dark theme.









Binary stars:-

Gamma1 and gamma2 Andromedae form a noted binary with colour contrast, gold and blue. The binary is a multiple system. AB: 2.5, 5; PA 63º, and separation 10". BC (the primary of which is gamma2) form a very close binary with an orbit of 61 years: 5.5, 6.3; currently the component is at PA 104º and separation 0.5"

Kappa Andromedae is a wide and rather faint binary: 4, 11; 194º, 46.8".

Pi Andromedae is alse faint and wide: 4.4, 8.9; 173º, 36".

Tau Andromedae: 5, 10; 329º, 52.5".

Phi Andromedae has a 370 year orbit: 5, 6.5; 154º, 0.5".

Omega Andromedae: 5, 12; 122º, 1.9".

Struve 3050 (And) RA: 23 59.5 Dec.: +33 43 Magnitudes: 6.6 6.6 Separation: 1.7 Position Angle: 335 Two equally bright light yellow stars are almost holding each other. This curious duo is positioned north of the most NE star of the big square of Pegasus.


M31 (NGC 224), "The Andromeda Galaxy", is the finest spiral galaxy in the heavens, and probably the most well known. The galaxy lies at about a fifteen degree angle from being edge-on; it has a bright oval nucleus. Its distance is approximately 2.3 million light years.
Dust lanes become visible in medium-sized telescopes.

M32 (NGC 221) is the brightest elliptical satellite of M31, although rather faint compared to the latter. This galaxy is located almost half a degree to the south of M31 and is best seen in large telescopes.

M110 (NGC 205) is another elliptical galaxy, and a larger companion to M31 but much dimmer. It lies about thirty-five arc-minutes NW of M31.

NGC 891 is rather faint, but quite a nice edge-on spiral with clearly distinguished dust-lane in large telescopes. It's four degrees due east of gamma Andromedae.


NGC 752 is an open cluster of perhaps a hundred rather scattered stars. It's about four and a half degrees south of gamma Andromedae, and two degrees west.


NGC 7662, sometimes called "Blue Snowball", this is a blue-green planetary nebula with a very faint central star which is apparently variable (estimated to range from 12 to 16 visual magnitude). The nebula is found about 2.5º WSW of iota


Binary stars:-

Zeta2 Aquarii and zeta1 Aquarii form a binary of two equal white stars with an orbit of 760 years. Zeta2 Aquarii is the primary: 4.4, 4.6; current PA 266º and separation: 2.3".

12 Aqr RA: 21 04.1 Dec.: -05 49 Magnitudes: 5.9 7.3 Separation: 2.8 Position Angle: 192 A clearly yellow primary has a moderately fainter bluish companion next to it, but almost mathed. The double stands in the region of the well known globular M2, that is south of Eps Peg, the star SW of the Square.

Struve 2944 is a nice triple system, with all three in a neat line. AB: 7.0, 7.5; PA 276º, separation 2.5".C: 8.4; PA 106º, separation 50".
The binary is 2º due east of kappa Aquarii.

Struve 2988 is a very attractive pair of equal stars: 7.2, 7.2; PA 101º, separation 3.5". The binary is 3º SW of psi1 Aquarii.


M2 (NGC 7089) is a globular cluster, compact and bright, about 50,000 light years away. The cluster is 5º N of beta Aquarii.

M72 (NGC 6981 is also a globular cluster, about 3º WSW of the Saturn Nebula (see below). It is one of Messier's least attractive objects.

M73 (NGC 6994) is another uninteresting Messier, a ‘cluster’ comprised of four unrelated stars about 1.5º east of M 72.


NGC 7009, "Saturn Nebula" is a planetary nebula quite spectacular in large instruments. It has ‘rays’ which extend from both sides of the main disc. The nebula is 1º west of nu Aqr. Burnham (p. 190) has a location chart.

NGC 7293, "Helix Nebula" (or the "Helical Nebula"), is another planetary nebula, given its name apparently because it is said to resemble the DNA double helix. It really is a ring nebula, only much larger and fainter than the more notable Ring Nebula in Lyra. The nebula is 1.5º W of upsilon Aquarii, or 21º due south of zeta Aquarii.


Binary stars:-

Beta Aquilae is relatively fixed, with a faint red dwarf companion: 3.7, 11.6; PA 5º, separation 13".

Zeta Aquilae - A difficult double star located approximately 83 light years from Earth. The primary component is a white dwarf shining at 3rd magnitude. The 12th-magnitude companion is found 6.5 arcseconds from the primary.

Pi Aquilae - A double star easily resolved with a 6-inch telescope into its two components of magnitudes 6 and 7, separated by 1.4 arcseconds.

11 Aql RA: 18 59.1 Dec.: +13 37 Magnitudes: 5.2 8.7 Separation: 17 Position Angle: 286 This pair contains a bright yellow primary and a much fainter blue attendant, but easily spotted thanks to the moderately wide separation. It is located just SW of the most NW naked eye star of Aquila.

Also the nice double Struve 2426 lies at its SE.

15 Aquilae - A yellow 5th-magnitude star with a 7th-magnitude companion 40 arcseconds away. It can easily be observed with small telescopes.

57 Aquilae - Another easy pair for binoculars or small telescopes. Its two components shine at 6th magnitude and are separated by 36 arcseconds.

GRS 1915+105 star A star system containing the most massive known stellar black hole.

Chi Aquilae is a close binary with the separation slowly decreasing: 5.6, 6.8; PA 77º, separation 0.5".

Struve 2404 (Aql) RA: 18 50.8 Dec.: +10 59 Magnitudes: 6.9 8.1 Separation: 3.6 Position Angle: 183 This is an attractive double with 2 orange stars, almost touching each other. The companion is only a bit fainter. The primary is deeply orange. The double lies completely NW in the constellation, that is SW of the most NW naked eye star of Aquila.

Struve 2449 (Aql) RA: 19 06.4 Dec.: +07 09 Magnitudes: 7.2 7.9 Separation: 8.0 Position Angle: 291 This little double lies far W of the main triple star pattern of Aquila, that is rather at the end of the tail of Serpens. A yellow primary stands with a slightly fainter blue friend, noticeably close to it.


B143-4 - A dark nebula located about 1.5 degrees to the west of Gamma Aquilae. Through amateur telescopes it appears as a dark,
starless area that stands out from the starry background. The nebula is over a degree in size, so when observing use a wide-field eyepiece and low magnification to fit it in the field of view.

NGC 6803 - A difficult 11th- magnitude planetary nebula, appearing as a stellar point even at high magnification.

NGC 6891 planetary nebula A bright disk and faint ring. Magnitude 12; diameter 1.2'; R.A. 20h 13m, Dec. +12° 35'


NGC 6709 - An open star cluster located five degrees southwest of Zeta Aquilae. Small telescopes show 30 stars spread in a diameter of 15 arcminutes.

NGC 6755 - A small cluster found 4.5 degrees west of Delta Aquilae, appearing as an elongated misty patch of light at low magnification.
If you use 150x or more the cluster is resolved into about a dozen stars with magnitudes between 12 and 13.


Binary stars:-

1 Ari RA: 01 50.1 Dec.: +22 17 Magnitudes: 6.2 7.2 Separation: 2.8 Position Angle: 166 This attractive double lies just right of Alpha and Beta Ari.

Gamma Arietis is a well-known binary of similar stars: 4.8, 4.8; PA 360º, separation 7.8".

Lambda Arietis is a wide binary: 4.9, 7.7; PA 46º, separation 37.4".

Epsilon Arietis is a closer binary of nearly equal stars: 5.2, 5.5; PA 203º, separation 1.4".

30 Ari is a fixed binary with wide component: 6.6, 7.4; PA 274º and separation 38.6".

33 Ari is also fixed, with a faint component: 5.5, 8.4; PA 360º, separation 28.6".

Struve 394 (Ari) RA: 03 28.0 Dec.: +20 28 Magnitudes: 7.1 8.1 Separation: 6.8 Position Angle: 162 It's located in the far east of the constellation, SW of the Pleiades. A fairly close double with a yellow star and a fainter blue brother next to it.

Struve 326 (Ari) RA: 02 55.6 Dec.: +26 52 Magnitudes: 7.6 9.8 Separation: 5.9 Position Angle: 220 This attractive double has beautiful colors, a light orange primary and a considerably fainter dark reddish secondary, moderately split. This pair lies NE of the brightest Alpha Ari, or SE of the Triangle.


NGC 772 is a strangely shaped diffuse galaxy with a spiral arm on the northwest. It's found about one degree ESE of Gamma Ari.


Binary stars:-

Zeta Aurigae is an eclipsing binary; an orange giant primary with a blue companion that orbits every 972 days (2.7 years).

Theta Aurigae is visible in large scopes: 2.6, 7.1; PA 300º and separation 3.6".

Omega Aurigae: 5.0, 8.0; PA 360º, separation 5.4".

Psi 5 Aur RA: 06 46.7 Dec.: +43 35 Magnitudes: 5.3 8.3 Separation: 36.2 Position Angle: 31 Noticeably, there are 8 stars E of the pentagon shape of Auriga, labeled from Psi 1 to Psi 8. The fifth one is a remarkable highly wide double of an obviously yellow primary and a much fainter light blue companion.

14 Aurigae is a multiple double, visible in larger scopes. The primary is 5.1, with three companions: B (11.1, 352º, 11"), C (7.4, 225º, 15") and D (10.4, 356º, 7.7").

Struve 644 (Aur) RA: 05 10.3 Dec.: +37 18 Magnitudes: 6.8 7.0 Separation: 1.6 Position Angle: 224 It lies just SE of the other double Omega Aur. It's a nice challenge to see the equally bright stars detached, a deep yellow and blue gem.

Struve 698 (Aur)RA: 05 24.2 Dec.: +34 51 Magnitudes: 6.6 8.7 Separation: 31.2 Position Angle: 345 It's located in the lower part of the pentagon, where you can find many stars. The double 14 Aur stands also here. Struve 698 is not far from the gorgeous open clusters M36 and M38. It's a considerably wide double of an orangish primary and a fairly fainter blue companion.

26 Aur RA: 05 38.6 Dec.: +30 30 Magnitudes: 6.0 8.0 Separation: 12.4 Position Angle: 267 It lies just NE of the southernmost star of the pentagon of the Charioteer. In fact, it is the AC pair, containing a bright yellow primary and a fainter blue companion, moderately separated.

Otto Struve 147 (Aur) RA: 06 34.3 Dec.: +38 05 Magnitudes: 6.6 10.0 10.6 Separation: 43/46 Position Angle: 73/117 A triplet in a real triangle figure? This one is a great example. A yellowish primary has two little bluish friends. This gorgeous trio lies east of the pentagon figure. Struve 928 lies just north, and Struve 929 just south of it.

Struve 928 (Aur) RA: 06 34.7 Dec.: +38 32 Magnitudes: 7.6 8.2 Separation: 3.5 Position Angle: 133 It lies just north of the lovely triplet Otto Struve 147 and the other double Struve 929. Two rather equal white stars are considerably close in contact.

Struve 929 (Aur) RA: 06 35.4 Dec.: +37 43 Magnitudes: 7.4 8.4 Separation: 6.2 Position Angle: 24 It lies south of the lovely triplet Otto Struve 147 and the other double Struve 928. It's a moderately close pair of a yellow primary and a slightly fainter blue companion.

Struve 872 (Aur) RA: 06 15.6 Dec.: +36 09 Magnitudes: 6.9 7.9 Separation: 11.3 Position Angle: 217 A slightly fainter orangish pink component stands next to a clearly yellow star, easily resolved. This pair is located just E of the pentagon shape of the Charioteer.


M36 is a rather faint cluster of about 50 to 60 stars, in a very compact area. A large scope is necessary to resolve the individual stars. To find M36, move west just across an imaginary line from El Nath to theta Aurigae.

M37 is the most spectacular of the three Messiers, and also the most easily found, as it lies midway between El Nath and theta Aurigae.

M38 is in the same field, just to the NW of M36. Some observers have described this cluster of about a hundred stars as having a cross-shape


Binary stars:-

Zeta Boötis is a very fast binary with a highly eccentric orbit of 123.4 years. The companion is currently fairly close (0.9") at PA 301º.

Epsilon Boötis was one of Struve's favourite double star systems: 2.5, 4.9; a bright yellow primary with a blue-green companion.
The orbit is so large it may as well be considered fixed: PA 339º, separation 2.8".

Kappa Boötis is a gorgeous double with colour contrast; the primary is yellow and the companion a deep blue. The binary is fixed at PA 235º, separation 13.4".

In the same field is iota Boötis: 4.9, 7.5; PA 33º, separation 38.5"

Mu Boötis is a triple system. AB are fixed: 4.3, 7.0; PA 171º, separation 108". The component B has a close companion C (magnitude 7.6) which is a rapid binary, with an orbit of 246.1 years. The 2000 values are PA 7º, separation 2.1".

Pi Boötis is a pleasant binary of two blue-white stars (4.9, 5.8; PA 108º, separation 5.6").

Xi Boötis is a rapid binary (4.7, 7.0) with orbit of 151 years. The primary is yellow, and the companion a white-pink. Currently the companion is found at PA 321º and 6.8" separation.

Struve 1785 is another attractive rapid binary, with orbit of 155 years. The companion can now be found at PA 173º, 3.3" separation.

Struve 1909 (44 Boo) is yet another rapid double, with an orbit of 225 years. In the year 2000 the companion will be at its widest separation for the next fifty years. Presently it's located at 54º, 2.2" separation.

Struve 1825 (Boo) RA: 14 16.5 Dec.: +20 07 Magnitudes: 6.5 8.2 Separation: 4.4 Position Angle: 163 This binary lies just N of the bright Arcturus. It is a pair with beautiful yellow and orange colors. But the separation is tiny, and the companion is plainly fainter.

Struve 1835 (Boo) RA: 14 23.4 Dec.: +08 27 Magnitudes: 5.1 7.6 Separation: 6.2 Position Angle: 192 This double contains a white primary and clearly close to it a highly fainter dark yellow companion. The double lies completely at the bottom border of the constellation, deeply south of Arcturus

39 Boo RA: 14 49.6 Dec.: +48 43 Magnitudes: 6.2 6.9 Separation: 2.9 Position Angle: 45 A deep yellow main star and a light yellow secondary are almost in contact. The companion is only a slightly fainter. This attractive yellow binary lies in the topmost area of the constellation, rather E of the last tail star of the Great Bear .

Struve 1910 (Boo) RA: 15 07.5 Dec.: +09 14 Magnitudes: 7.5 7.5 Separation: 4.3 Position Angle: 211 This pair has clearly two equally bright yellow stars, almost fully attached. You can find it in the most SE corner of the constellation, far SE from Arcturus.


NGC 5248 is a very compact spiral galaxy in the southwestern corner of the constellation, ten degrees south of Arcturus and one and a half degrees west. (Two degrees north is the rapid binary BU 612 (6.3, 6.3) with period 22.4 years.)


NGC 5466 is a large but quite dim globular cluster. It's found nine degrees north of Arcturus and one and a half degrees west. (The Messier object M3 is five degrees due west in Canes Venatici.)


Binary stars:-

Struve 485 is an outstanding binary surrounded by a host of glittering 10- and 11-magnitude stars which make up the open cluster NGC 1502. This is a wide and easy binary, and a lovely sight NGC 1502 is found half way between alpha and beta Cam, and about 55 arc minutes west.The brightest star in this group is the primary of Struve 485, found at the centre. The binary's vital statistics are AB: 6.1, 6.2; PA 304 degrees, at separation 18.1".

At virtually the same location is a second binary, Struve 484, which is much fainter: AB: 9.0, 9.5; PA 132, 5.3".

Struve 1051 is a striking triple system of similar stars. AB: 6.5, 7.7; PA 284 degrees, separation 1.1"; ? 7.8, PA 82 degrees and separation 31.5". This very nice system is found in an otherwise desolate region: 7h, 26m, 35s; +73 degrees, 4', 58". It's well worth the detour.

Struve 1694 is a wide pair of nearly equal stars (5.0, 5.5; PA 326 degrees, separation 21.6")

Beta Camelopardalis features a pale yellow primary and a very wide, much fainter, companion: 4.0, 9.0; PA 208 degrees, separation 80".
Component B has a closer companion, named "b", an 11-magnitude star at 14.8" and PA 168 degrees.

1 Camelopardalis RA: 04 32.0 Dec.: +53 55 Magnitudes: 5.7 6.8 Separation: 10.3 Position Angle: 308 At the NW of Capella, but in the area of Camelopardalis, lies this pair. It's only surrounded by tiny stars at its W and E. The double itself contains a white main star, and moderately away from it a slightly fainter bluish friend .

Struve 1122 (Cam) RA: 07 45.9 Dec.: +65 09 Magnitudes: 7.8 7.8 Separation: 15.4 Position Angle: 5 In the constellation of the Giraffe, NE of Capella, lies a nice double of two equal white stars, easily split thanks to the moderately wide separation between them.


NGC 1502 is the finest star cluster, a small group of perhaps fifteen stars with the binaries Struve 484 and Struve 485 at its centre (see above).

Kemble's Cascade is a string of mostly eighth-magnitude stars (nicely seen in binoculars) which seem to "splash" into the cluster.
The asterism is named for Father Lucian Kemble, a Franciscan and avid Canadian amateur astronomer who first drew attention to it in the late 1970s.


NGC 2403 is a fine spiral galaxy about 10 million light years away. At ninth magnitude it's easily seen in medium sized telescopes, although greater detail is of course obtained in larger scopes.

NGC 2523 is an extremely faint barred spiral galaxy with very curious features. With a visual magnitude of 13, it is only accessible to larger telescopes.


Binary stars:-

Zeta Cancri is a notable triple system comprised of a close binary with a period of 59.5 years and a more distant star, component C, much longer period of 1115 years. (These values are recently published revisions; formerly the two orbits were thought to be 59.7 and 1150 years.) This distant companion also has its own binary star, which revolves about zetaC every 17.6 years. It has never been seen, and its existence has only been discovered through a particular wobble of zetaC. The unseen star is thought to be a white dwarf.

Phi Cancri is a binary of two identical white stars (5.5m, 6m): the PA is 217º and separation is 5.1".

Iota Cancri is a wide binary (4.5, 6.5) with a striking colour contrast: yellow and blue. PA 307º separation 30.5".

Finally, for the perseverant, there are a number of binary systems visible in the Beehive Cluster (see below). We'll point out two of them, very close to each other. The brightest is Struve 1254. The primary is a bright 6.5m, with a 9.0m companion B at 54º, 20.5". Then there are two more components: ? 8.0, 342º, 63.2"; ? 9.0, 43º, 82.6". To find this group, first locate epsilon Cancri, which is near the centre of the Beehive Cluster and the brightest star in this cluster. Just to the northwest of this star, less than a minute's distance, you'll find this binary system.

In the same field (slightly west and less than a minute south of Struve 1254) is the nice quadruple called beta 584, comprised of 7.0, 12.0, 7.0, and 6.5 visual magnitudes. AB is the most difficult to find, for the companion is a faint 12m star at 291º and separation of only 1.2". AC: 156º, 45"; AD: 241º, 93".

Phi 2 Cnc RA: 08 26.8 Dec.: +26 56 Magnitudes: 6.3 6.3 Separation: 5.1 Position Angle: 218 This striking bright pair contains two white stars, equally shining and trying to touch each other. Phi 2 lies SW of that other splendid colored double Iota Cancri in the upper area of the Crab.

Struve 1245 (Cnc) RA: 08 35.8 Dec.: +06 37 Magnitudes: 6.0 7.2 Separation: 10.3 Position Angle: 25 A traditional yellow and blue double containing a not much fainter companion and holding a moderately wide gap between the twins. It stays completely south in the constellation, it is rather sitting just north of the head of Hydra


M44 (NGC 2632) is better known by the name the Beehive Cluster, or the Latin equivalent: Praesepe, which not only means a hive but also a crib, or manger. This is a bright open cluster clearly visible to the naked eye on a dark enough night, and best appreciated with binoculars or small scope. One of the largest clusters, its 1.5 degree size is equivalent to three full moons end-to-end. Its distance is calculated at between 520-590 light years.

M67 (NGC 2682) sits about two degrees west of alpha Cancri and south of the Beehive about nine degrees. Visually unremarkable, yet this deep sky object is renowned for its venerable age: it is now believed that the cluster is approximately 10 billion years old.
Its estimated distance is 2500 light years and there are about five hundred stars in the cluster, tightly packed.

Canes Venatici

Binary stars:-

Alpha2 and alpha1 CVn form a celebrated fixed double star system. Note that the primary is alpha2, since it is slightly east of its companion. While both stars are usually reported to be blue-white, some find them slightly different, perhaps soft blue and yellow, or two shades of white.

25 CVn (Struve 1768) is a visual binary with an elegant orbit of 240 years. Presently, the companion is at near maximum separation, with a PA of 100 degrees and separation 1.8".

2 CVn RA: 12 16.1 Dec.: +40 40 Magnitudes: 5.8 8.1 Separation: 11.4 Position Angle: 260 This marvelous binary lies W of that other fine double Alpha CVn. It consists of a fairly bright golden sun with moderately close to it a fainter blue companion.


M3 (NGC 5272) is a wonderful globular cluster found roughly halfway between Cor Caroli and Arcturus (in Bootes). Considered one of the finest globular clusters in the entire heavens, you'll need a large scope to resolve its individual stars. The cluster is about 45,000 light years away.


M51 (NGC 5194) or The Whirlpool Galaxy is the finest galaxy in Canes Venatici. This spiral, found just southwest from the tip of the Big Dipper's handle, was the first spiral galaxy to be discovered (in 1845 by Lord Ross at his castle in Ireland). Some say the galaxy is 14 million light years away, others that it is twice that. In any case, you'll need a large telecope and a fine evening to enjoy its delicate
detail, which includes an appendage system (NGC 5195), another galaxy seemingly hanging onto one of its extended arms.

M63 is sometimes called the Sunflower Galaxy, by its numerous arms, which Burnham describes as "reminiscent of showers of sparks thrown out by a rotating fiery pinwheel". Fairly bright, at 8.1 magnitude, it has a very condensed centre. The galaxy is found five degrees north-northeast of Cor Caroli.

M94 is another spiral, seen practically face-on, and sometimes described as "comet-like". This is a very compact circular spiral and very bright (8.1 magnitude). To find it draw a line between Cor Caroli and beta CVn, and at the half-way point draw a perpendicular off to the northeast. About two degrees up this perpendicular
is found M94.

M106 (NGC 4258) is another bright spiral. Burnham doesn't list this object as a Messier, but gives a fine photograph. The galaxy is six degrees north north-west of beta CVn.

Below are listed a selected number of galaxies considered the best of the non-Messiers. NGC 4244: a large edge-on spiral, found eight degrees west of Cor Caroli.

NGC 4485 and NGC 4490 are two splendid galaxies in the same field: 4485 is more compact (this one is sometimes called the Cocoon Galaxy), while 4490 is larger and brighter. Located less than one degree northwest of beta CVn.

NGC 4631: very large and bright, seen edge-on. Found in a rather barren field, six degrees south of Cor Caroli and two degrees west.
In the same field are two more galaxies, NGC 4656 and 4657, just southwest of 4631

Canis Minor

Binary stars:-

Procyon A and Procyon B form an extremely difficult binary. In fact the companion, which is a white dwarf with a diameter of only twice that of Earth's, was first seen only in 1896. Since then its orbit, which is nearly circular, has been calculated to be 40.65 years.
In 2000 the values are: 0.4, 10.3; PA 150º, separation 4.6".

No deep space objects


Binary stars:

Alpha2 and alpha1Cap form an optical binary of yellow and orange stars: 3.6, 4.2; PA 291º, separation 378". Each star is a visual binary: Alpha1 Capricorni: 4.6, 9.2; 221º, 45.4". Alpha2 Capricorni: 3.5, 9.5; 156º, 154".

Beta Capricorni is a wide visual binary with a nice colour contast, yellow and blue: 3.1, 6; PA 267º, separation 205".

Tau Capricorni is a visual binary with a 95 year orbit: 5.5, 7; PA 107º, separation 0.4". The PA is increasing, the separation is decreasing; at the year 2000 the values will be 123º and 0.2".

Globular cluster:

The only Messier in the constellation is M30 (NGC 7099), a globular cluster about 40,000 light years away. It has a very concentrated centre, with a number of star chains (or strings) from the centre to the periphery. M30 is 3º ESE of zeta Capricorni.


NGC 6907 a barred spiral galaxy of mag 11.7 and with a apparent diameter of 3.4'.



Binary stars:-

Gamma Cassiopeiae has a faint companion, made doubly-difficult to see because of the brightness of the primary: 2.5, 11; PA 252º and separation 2.3".

Eta Cas is a fine binary with colour contrast, yellow and red. Some observers see them as more gold and purple. The companion orbits every 480 years. Present values are: 3.4, 7.5, PA 315º, separation 12.7".

Lambda Cas has two nearly equal stars: 5.5, 6; PA 179º, 0.5".
Iota Cas is a triple system, with AB a visual binary with an orbit of 840 years. AB: 4.6, 6.9; presently at PA 231º and separation 2.5".
? 8, PA 114º, 7.3".

Omicron Cas has a faint companion: 4, 11; 302º, 33.6".

Phi Cas is another multiple system, with rather wide components. The binary lies on the edge of NGC 457 (see below). AB: 5, 12; 208º, separation of 48.6".C 7; 231º, 134".

Sigma Cas: 5.0, 7.1; 326º, 3".

Struve 3062 is a visual binary with orbit of 106.8 years: 6.4, 7.5; presently 322º and separation 1.5".

Struve 163 (Cas) RA: 01 51.3 Dec.: +64 51 Magnitudes: 6.8 8.8 Separation: 34.8 Position Angle: 35 A wide binary with beautiful colors, lying just above the most NE star of the "W" figure. The main star is nicely orange colored, while the faint secondary is bluish.


M52 (NGC 7654) is an open cluster of about 120 stars. It's found 6º NW of rho Cas. Burnham gives the best method of finding the cluster: draw a line from alpha Cas to beta Cas, then continue this line, doubling its length. The cluster is just past the end point, about another quarter-length.

M103 (NGC 581) is another open cluster, with about forty stars. It's 1º NE of delta Cas, or 1.5º due north of chi Cas.

NGC 457 is an open cluster about 4º SE of gamma Cas. The star phi Cas is considered a part of this cluster. This star is one of the most luminous known, with at least 200,000 times the light of the sun.

NGC 7789 is a rich open cluster of perhaps a thousand stars. It's 3º SW of beta Cas, lying just between rho Cas and sigma Cas.


Binary stars:-

Beta Cephei is a blue giant with a faint companion easily resolved: 3.2, 8; PA 250º, separation 13.6"

Delta Cephei is a fixed double, a yellow giant with blue companion: 3.8, 7.5; PA 191º, separation 41".

Xi Cephei is considered to be the most attractive binary in Cepheus, a blue-white primary and yellow (or reddish) companion that orbits
every 3800 years: 4.4, 6.5; PA 275º, separation 8.2". 6.5;

Kruger 60 is a famous binary only 12.9 light years away, comprised of two red dwarfs. Observers had reported seeing flare-ups on the surface of the companion, which is orbiting the primary every 44.6 years. AB: 9.8, 11.4; presently the companion is at PA 109º and separation 3.2". The binary is less than one degree SSW of delta Cephei. Burnham has a finder's chart (p. 600).

Struve 2816 is a multiple binary, a very attractive triple:
AC: 6.3, 8.1; 121º, separation 11.7" ? 8.0; PA 339º, 19.9"

In the same field are Struve 2813 and Struve 2819, all centred in the middle of the large but faint diffuse nebula IC 1396, just south of mu Cephei.


NGC 188 is a faint globular cluster of 150 stars. Its significance lies in the fact that it is extremely old: it is estimated to have formed ten to twenty billion years ago. The easiest way to find it is drop down four degrees from the Pole Star, toward the star called "2 UMi", which is nevertheless in Cepheus. The cluster is just to the southwest of this star.

NGC 6939 is a fine open cluster of about eighty stars in a very rich field that includes NGC 6946, a face-on spiral galaxy. The cluster is found about 2.5 degrees south of theta Cephei, or about two degrees SW of eta Cephei (thus it forms a rough triangle with these two stars).


IC 1396 Emission Nebulae Size: 49' RA: 21h 39' Dec: +57 30'


NGC 6946, a face-on spiral galaxy


Binary stars:-

Gamma Ceti (Struve 299) is perhaps the finest binary in Cetus. Some observers find a colour contrast, yellow and blue: 3.5, 7.3; PA 294º, separation 2.8".

Nu Ceti: 5.0, 9.5; PA 83º, separation 8".

Struve 186 is a close binary of two equal stars, with an orbit of 170 years: 7.0, 7.0; currently PA 60º and separation 1.1".

Beta 395 is a very rapid visual binary, with orbit of 25 years: 6.3, 6.4; presently PA 289º and separation 0.5".


M77 (NGC 1068) is a small spiral galaxy seen face on, one of the so-called Seyfert gallaxies, which means it has a radio source - a feeble example of a quasar. M77 is about 50 million light years away, and is found one degree SE of delta Ceti.

NGC 247 is a large and fairly bright spiral galaxy with compact nucleus. It has a slightly irregular shape on one end where the spiral arm has a hollowed out appearance on long-exposure photographs. It is located about 5 degrees north of its famous neighbor in Sculptor, Galaxy NGC 253. It is about the same size as NGC 253, but two magnitudes fainter. Both galaxies are fairly close to us at 12 million light years.

Coma Berenices

Binary stars:-

Alpha Comae is a rapid binary of two equal stars (5.05, 5.08). The companion orbits every 25.87 years and is presently decreasing; the current (2000) separation is less than 0.05". The orbit is an unusual one, seen perfectly edge-on.

Zeta Comae is a fixed binary: (6.0, 7.5; PA 237º, separation 3.6").

17 Comae is one of the members of the Coma Star Cluster. The primary is white, the companion a soft blue: 5.3, 6.6; PA 251º, separation 145.3". From gamma Comae follow the slight arc of stars south that bend to the east. First comes 14 Comae, then 15, and finally 17.

24 Comae is even more spectacular: a fixed binary with an orange primary and emerald component. (5.2, 6.5; PA 271º, separation 20.3"). This binary is located eight degrees west of alpha Comae and one degree north.

35 Comae is a slow double with an orbit of over 300 years. However, unlike most long period binaries, this one is presently quite close.
The companion is beginning to emerge from its close pass with the primary, gradually lengthening its separation, recently having achieved one arc second of separation. The present values are: 5.2, 7.2; PA 185º and separation 1.04". 35 Comae is in a fairly barren part of the sky, found five degrees northwest of alpha Comae.

Struve 1633 is a very pleasant fixed binary: 7.1, 7.2; PA 245º, separation 9.0". To find it start from gamma Comae, then drop down exactly one degree south where you'll find 14 Comae. Struve 1633 is one degree to the west.

Struve 1639 is a closer binary: 6.8, 7.8; PA 327º, 1.6". This is a slow moving binary with an orbit of 678 years. This double star makes a small triangle with 12 Comae and 13 Comae. Start at 14 Comae and look south. The bright star to the east is 15 Comae, while below this and to the west is 13 Comae. Nearby, immediately southwest, is 12 Comae. Now look between these two stars to the southeast, where you'll find the third point in the triangle. This is Struve 1639. (Not shown on the chart due to crowding.)

Struve 1932 (CrB) RA: 15 18.3 Dec.: +26 50 Magnitudes: 7.3 7.4 Separation: 1.6 Position Angle: 259 This is another pretty double of two equally bright yellow stars nearly touching each other. It lies just W of the brightest Alpha CrB.


The Coma Star Cluster is best seen in binoculars, the cluster fills the entire field of view: about 40 stars spread out over a five degree area. The cluster was once known as the tuft of hair at the end of Leo's tail. It now constitutes Berenice's golden tresses. The cluster extends south from gamma Com (which is not, however, a member). At about 270 light years away, the cluster is one of the closest to our solar system. The brightest member of the cluster is 12 Comae. Other fourth-magnitude members are 13 and 14 Comae, and another thirty or so fainter stars go to make this one of the loveliest sight in the heavens.

M53 is a globular star cluster one degree northeast of alpha Comae. The brightest Messier in the constellation (7.7), it tends to be most impressive with larger telescopes, which are needed to resolve the individual stars. The cluster is thought to be 65,000 light years away.


M64, the Black Eye Galaxy, is a bright (8.5) compact spiral one degree east-northeast of 35 Comae. The "black eye" can only be seen under ideal conditions with large telescopes. The galaxy is over 20 million light years away.

M85 is a bright spiral galaxy and member of the Virgo Galaxy Cluster, most of which is found about five degrees further south.
All the remaining deep sky objects discussed also belong to this cluster.

M88 is a many-armed spiral galaxy some forty million light years away. Quite bright (9.5), it's a favourite with many Messier observers.

M91 (NGC 4548) is another spiral galaxy, but is a rather confusing object, sometimes being labelled M58. It is a rather faint galaxy (10.2) and one wonders why, with so many galaxies in the region, spreading down through Virgo, that this one was chosen by Messier.

M98 is a faint (10.1) spiral seen practically edge-on, lying just half a degree west of 6 Comae.

M99 is roughly one and a half degrees east-southeast of M98. An open spiral seen face on, its several arms are visible in large scopes. It has a brightness of 9.8.

M100 is the largest of these spiral galaxies, although difficult to appreciate in small telescopes. It's seen face-on.

NGC 4565 is a well-known edge-on spiral with highly visible dust lane from end to end. It's the largest galaxy of its type and has a visual magnitude of 9.6. The galaxy is found one degree due east of 17 Comae. Coma Berenices has many more deep sky objects, particularly the southern regions, where it borders Virgo. This is a fertile part of the sky to investigate, as the evenings grow a little warmer and more inviting.

Corona Borealis

Binary stars:-

Gamma CrB (Struve 1967) is a close binary with an orbit of 91 years. The PA is 265º and separation about 0.2".

Eta CrB (Struve 1937) is a fine binary with orbit of 41.5 years. Presently the companion can be found at PA 47º and separation 0.9".

Zeta2 and zeta1 CrB (Struve 1965): a pleasant pair of blue-white stars with 5.0 and 6.0 magnitudes; PA 305º, separation 6.3". Note that zeta2 is the primary.

Sigma CrB (Struve 2032) is a slow binary, with a period of a thousand years. Currently the companion is at PA 236º and separation 7.03"

Theta CrB - Magnitudes 4.3, 6.3: From WDS; P.A. 199d, separation 0.8"

Nu1 and nu2 CrB (Struve I 29) form a very wide (but only optical) pair of orange giants, quite suitable for binoculars: PA 166º, separation 372".

Otto Struve 305 (CrB) RA: 16 11.7 Dec.: +33 21 Magnitudes: 6.4 10.2 Separation: 5.4 Position Angle: 263 A deep yellow primary with fairly close to it a bluish little sun. This attractive pair is located above the eastern tip of the crown. Also the nice pair Sigma CrB stands NE of it

The only deep sky object is the Corona Borealis Galaxy Cluster. This group is very faint but quite spectacular for those with the proper equipment. The cluster is comprised of over four hundred galaxies in an area of about one degree (the width of your thumb). The galaxies are extremely distant, over a billion light years away, and consequently are very faint. The brightest of the group are 16.5 visual magnitude. To find the cluster, move two degrees west of alpha CrB and north almost a full degree. In the same field, southwest, is the sixth magnitude binary Struve 1932 (PA 57, separation 1") with a period of 203 years.



Edited by tuckstar
Alter a few mistakes
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