Sagittarius - Scorpius- Scutum - Serpens- Sextans

SAGITTA

A small but distinctive group containing some beautiful fields. It actually extends some distance east of the four little stars which form the arrow itself.

Groups of stars

1. Fine bright group of α , β , δ and ζ . Note the curving line stretching from delta.

2. ζ . Beautiful sprinkles around this star.

Wide doubles

ζ Aql. 3 North of this star is a notable wide pair of 5.7 and 6.4.

2 and 3. These make a similar fine wide double.

9. Note a tiny 9m. equilateral triangle closely NE. Near the cluster M.71.

15. A 5.9m star with a 6.8 companion.

Close doubles

ε . A beautiful coloured double 90" apart, and of mags 6 and 7.

Hh630. A harder pair of magnitudes 7 and 9. Distance 29".

ζ . In a superb field, has a distant 7m companion.

Variable stars

U (6.4-9.0) An eclipsing binary; one of a small rectangle whose other stars are of 7.9, 8.1 and 8.5m.

BF (8.0-9.0) A red star in a very dense field. A chart is supplied.

SAGITTARIUS

The richest region of the entire sky, the centre of our Galaxy, lies beyond the glowing star-clouds of the Archer. Best seen from the USA or Southern Europe, the most notable part of the group to the eye is the large, symmetrical collection of second- and third-magnitude stars affectionately called the "teapot" because of its shape.

Groups of stars

1. 18h 00m,-2250'. Small oval of brightish stars.

2. Small bright group, including 24 (5.7).

3. μ (4.0). Beautiful fields between this star and gamma Scuti.

4. o and π . Two members of a beautiful large and bright group.

5. ω , 59, 60 and 62. Beautiful bright cross.

6. Large, regular arc, directly east of η .

Wide doubles

7 and 9. Both of these are closer pairs. 7 is the best - 6.9 and 8.5, distance 35". In the Lagoon Nebula.

15 and 16. A third star is visible.

o. A star with a 6m associate NW.

52. Forms a wide pair with 51, one magnitude fainter at 5.7.

53. In the same field, this is a closer pair of 6.1 and 6.2.

β1,2. A fine, wide pair in a rich field.

Close doubles

GC25327. A close pair of magnitudes 5 and 7.

P.278. A lovely white pair of stars separated by 121". Mags are 6.5 and 7.0.

P.281. Though distant at 196" this object is quite faint - both 8th mag.

Variable stars

RY (6.5-14) A star of the unpredictable R Coronae type. It can be estimated at maximum with three stars of 5.6, 6.5 and 6.9 to the SE, and is closely North of a 7.4m star; when you feel the need to use this star as a comparison, you will have to make this observation known, as RY Sgr will probably be entering one of its unpredictable fades.

UX (7.6-8.4) This makes a triangle with two bright stars, and the fainter of these has a companion of 8.0m which you can use for this red variable.

AQ (6.6-7.6) A chart is supplied for this deep red star.

V356 (6.9-8.0) An eclipsing binary near 29 (5.4), with a star of 8.1 between the two serving to note when V356 is at or near minimum.

V505 (6.4-7.6) A star of the same type, with a period of only 1.25 days. It is exactly halfway between 61 Sgr and a 6.2m star, and there is a fainter one of 6.8m closely SW of the variable.

Note : there are several Mira stars in Sagittarius that are easily visible with binoculars at maximum. I have provided predictions for the following examples:-R, RR, RT, RU and RV.

Clusters and Nebulae

M.8 (NGC 6523). The beautiful Lagoon Nebula, visible with the naked eye. It has an attendant cluster, but needs good altitude for an impressive view.

M.21 (NGC 6531). With 8x30's, you will see several bright, and many faint, stars before an irregular nebulosity.

M.24 (NGC 6603). Not so much a cluster as a rich star-cloud. Twenty stars are visible with 10x80. A bright elliptical glow in small binoculars.

M.22 (NGC 6656). A very bright globular cluster, looking rather like a comet, with a noticeably brighter centre in 8x30.

M.25 (IC 4725). A dense cluster of several stars beyond which can be seen a nebulous glow.

M.17 (NGC 6618). The Omega or Horseshoe nebula. Imre Toth, using 10x80's, sees this as "Triangular, with apex to the South and the brightest part to the North... bright grey colour".

M.18 (NGC 6613). An open cluster appearing to the same observer as a bright grey nebulosity, rather whiter in parts.

M.20 (NGC 6514). The famous and photogenic Trifid Nebula has a faint greenish tinge, with several stars involved in it.

M.23 (NGC 6494). A nebula visible as a bright diffuse streak.

M.54 (NGC 6715). A moderately bright globular in a fine field near zeta Sgr.

M.55 (NGC 6809). Another globular, much brighter, but more isolated.

NGC 6530 Many stars are visible in this cluster, which lies in a really beautiful region.

NGC 6716 Again, some stars can be resolved, before a white glow.

SCORPIUS

Like the previous constellation, this is a magnificent group in every possible way. Also alike insofar as you need altitude to appreciate its best objects!

Groups of stars

1. π (3.0), is one corner of a large, bright lozenge.

2. Bright quadrilateral formed by ξ , 11, ψ and χ .

3. The "sting" is extremely beautiful with any optical aid. Its brightest star is λ (1.7).

Wide doubles

2 and 3. A wide but rather unequal pair in group (1).

ω . A bright pair in a brilliant field.

μ1,2. A similar beautiful pair.

ζ2. This star has two distant companions.

Close doubles

ν . Two stars separated by 41".

22. A closer, fainter pair near Antares. Mags 5 and 7.

P.289. This is a good test object for average-to-large glasses, of magnitudes 5.7 and 7.7 but only 24" distance.

P.291. A beautiful equal pair, 96" apart.

P.292. Again equal, but 2 magnitudes fainter, the 8th-mag stars being 88" apart.

P.293. Rather closer at 65 seconds, but slightly brighter.

P.294. This seventh-magnitude pair is wider (162") and easy.

P.295. A fainter object, 217 seconds apart.

Variable stars

SS (7.5-9.5) An irregular variable of the orange type K. A chart is supplied.

SU (8.0-9.4) This rather faint red star makes a right-angle with two stars of 5.9 and 6.5. Between the latter and SU lie two useful stars of 8.6 and 9.2.

AK (7.8-9.3) A nebular variable near mu. A chart is supplied.

BM (6.0-7.9) Though brighter, this is difficult to estimate as it is in the brilliant cluster M.6

FV (8.0-8.7) An Algol-type star, south of which is a vertical Y of (North to South) 7.9, 7.8, 8.3 and 8.6.

V393 (7.4-8.3) Near the wonderful cluster M.7, this eclipser is one of a small right-angle whose other stars are 7.2 and 7.8m.

V453 (6.8-7.3) Another eclipsing star, this time of the β Lyrae type. A fifth-magnitude star nearby forms a triangle with two to the E., of 6.8 and 7.0.

V856 (6.8-8.0) A nebular variable, and a wide double. Its companion is of 6.7m and is found directly to the N. A useful little right-angle lies just SW of the variable. Its members are of 7.0, 7.6 and 8.0m.

Clusters and Nebulae

M.4 (NGC 6121). A large globular cluster, quite bright and conveniently close to Antares.

M.6 (NGC 6405). A beautiful coarse cluster that binoculars will partially resolve into about a dozen stars.

M.7 (NGC6475). This is one of the most superb of all binocular objects. Easily visible with the eye, your bins should reveal around 20 stars here.

NGC 6231 A cluster which streams out towards ζ , this is yet another showpiece of the Scorpion.

NGC 6322 This appears as five stars in a Y-shape before a misty patch.

SCUTUM

Although a small group, this contains some interesting objects in addition to the brilliant star-cloud easily visible to the naked eye. Many of the more recent constellation figures had double-barrelled names, such as Columba (formerly Columba Noachii, or Noah's Dove) or Sculptor (ex Apparatus Sculptoris, the Sculptor's Tools). Scutum was another of these, its former name being Scutum Sobieskii, named after a Polish nobleman. (That's a nobleman from Poland, not a chap who got rich quick from selling furniture-buffing products...)

Groups of stars

1. Long trail extending from the variable R, to the 4th-mag. α .

2. 18h 51m, -0445'. Group of 8-9m stars in the form of a 7. A small line stretches from here to 7 and 8 Aquilae.

3. γ (4.7). A fine region E., including a red star.

Wide doubles

ε . A star with a fainter companion to the SE.

γ . This star has a bright associate closely E of it.

Close doubles

Σ2391. A faint, rather hard pair. Magnitudes 6 and 8, 38" apart.

Variable stars

R (4.5-8.4) A well-observed RV Tauri star which has been studied by amateurs for many years. It has recently emerged that this star displays chaotic behaviour, and those amateur observations, made by members of bodies such as the AAVSO, BAA and so on, are proving very important - a good example of how one branch of study feeds into another, this time amateur astronomy providing food for the Mathematicians. Why not have a look yourself - you'll get a bonus view of the "Wild Duck" as well. R Scuti is one of a little quadrilateral (other stars are 6.1, 6.7 and 7.1m).

S (7.0-8.0) A deep red star; one of a flattened pentagon whose other stars are of (E to W) 7.0, 7.0, 7.3 and 7.9.

RZ (7.9-9.0) I have provided a chart for this eclipsing binary.

Clusters and Nebulae

M.11 (NGC 6705). A bright cluster visible as a hazy triangular patch. In small instruments, it well-deserves its nickname of the Wild Duck - it really does look like a flock of ducks flying in a V formation, with a brighter orange star near the centre.

SERPENS

The only double constellation in the sky, made up of Serpens Caput (the head) and Cauda (the tail) though objects are named as though the group were one. The idea is that Ophiuchus, who is struggling with the snake, has pulled the poor thing in half! That aside, Serpens contains many fine fields, notably in the E.

Groups of stars

1. Sweep the "head" of ι, β , γ and κ. The last of these is reddish. There is another fine region just W, where there are no less than 8 stars bearing the Greek letter τ !

2. The area of 4, 5 and 6 is worth scrutiny with larger glasses.

3. ζ . This makes a neat triangle with two fainter stars.

4. η (3.4) is in a rich field of bright stars.

Wide doubles

ψ . This 5.8m star has two fainter associates.

47. A red star with two fainter companions, one of which is FQ Ser, slightly variable.

ξ . A bright pair, though separated by three mags.

64. An attractive equal double, both 6m.

Close doubles

Σ1919. Rather hard for binoculars, with a distance of only 25". The mags are 6 and 7, and this is said to be a coloured pair. How do they appear to you?

θ . Not normally considered to be a binocular double because of its rather small separation of 22", this is a superb equal pair which I have to say I find reasonably easy with 10x50s.

Variable stars

τ4 . (5.9-7.0) A red star in the "tau's" and well-served with comparisons; τ1 is 5.5, τ2 is 6.1 and has two neighbours of 6.7 and 7.6.

R (6.7-13.4) A Mira star easily found between β and γ . Its period is very nearly a year to the day, and I have supplied predictions for it. R Ser is one of a regularly-spaced line of three (other stars are 7.3 and 7.4) and its redness at maximum will distinguish it.

Clusters and Nebulae

M.5 (NGC 5904). A large, blazing globular near the 5m star 5 Serpentis. A real bunch of fives! With small glasses, a bright nebulous star.

IC 4756 This is a really splendid cluster, appearing as a double row of stars of assorted brightnesses. The southern branch is more noticeable; a good object to try and draw.

M.16 (NGC 6611). Long-exposure photographs of the Eagle Nebula have become practically de rigueur in space documentaries, science-fiction movies and the like. The Hubble Space Telescope recently provided breathtaking pictures of this object as a giant stellar nursery, inside which one could lose the entire solar system with no difficulty at all.With giant telescopes it really is impressive of course, though the binocular observer will have to be content with rather less. Using 10x80 glasses Imre Toth says of it "the North edge is the brightest part, silver-grey in colour". There is also an attendant cluster, some stars of which you may see.

SEXTANS

A small, faint group below Leo, with few objects of interest

.

Groups of stars

1. ε (5.4) is in an attractive region of fairly bright stars.

2. 25 (6.1) lies in an area scattered with wide pairs.

Wide doubles

17 and 18. An attractive red and blue object, good for small bins.

25. About 1 south is an equal (7.0m) wide double.

41. Note an 8th-mag companion SW. A fine field with large glasses.

Close doubles

9. A faint but wide pair. Mags 6 and 9, distance 52". Primary is red.