1.0 by 0.8 arcmin

Based on a recessional velocity of 4760 km/sec, NGC 6901 is about 220 million light years away. Given that and its apparent size of 1.4 by 0.6 arcmin, it is about 90 thousand light years across.

5.6 by 3.9 arcmin

One of a pair of galaxies (probably unrelated to NGC 6902). 1.3 by 1.0 arcmin

One of a pair of galaxies (probably unrelated to NGC 6902). 0.6 by 0.5 arcmin

1.5 by 1.2 arcmin

1.5 by 1.5 arcmin

(Note: A few sites erroneously list M5 as NGC 6904; if you arrived at this entry because of that, see NGC 5904, instead.) Per Dreyer, NGC 6904 (= John Herschel's GC 4571, 1860 RA 20 15 46, NPD 64 41.5) is a "cluster, small, very little compressed, with stars from 10th to 11th magnitude". Herschel's original description states that the position is for the brightest member of the cluster, which he estimated as 9th magnitude. The position precesses to RA 20 21 42.8, Dec +25 45 07, less than 0.1 arcmin from the 8th-magnitude star, so the identification is certain. The "cluster" is a 4 arcmin wide scattering of just a few stars, but with sufficient brightness to stand out against the background of the Milky Way. Whether it is a physical group or a chance alignment of unrelated stars appears uncertain, but it is certainly the "object" seen by Herschel.

1.6 by 0.8 arcmin

Per Dreyer, NGC 6907 (= John Herschel's GC 4573, 1860 RA 20 16 44, NPD 115 14.9) is "considerably faint, considerably large, very little extended, very gradually little brighter middle, mottled but not resolved, 3 stars preceding". The position precesses to RA 20 25 05.7, Dec -24 47 55, about 0.7 arcmin north of the center of the galaxy, but well within its outline, so the identification is certain. Based on a recessional velocity of 3180 km/sec, NGC 6907 is about 150 million light years away, in fair agreement with redshift-independent distance estimates of 110 to 135 million light years. Given that and its apparent size of 3.3 by 2.7 arcmin, it is about 130 thousand light years across. NGC 6908 is superimposed on the northeastern arm of NGC 6907, and must lie in front of it. The two galaxies' recessional velocities are nearly the same, which may mean that they are at nearly the same distance, and gravitationally interacting; if so, that may explain the slightly distorted shape of NGC 6907. However, there is no sign of gravitational effects on NGC 6908, so the galaxies may be several million light years apart, and simply an optical double.

Per Dreyer, NGC 6908 (= Marth 411, 1860 RA 20 16 46, NPD 115 15) is "extremely faint, very small, a little extended, with h2076 preceding", h2076 referring to NGC 6907. It should be kept in mind that in an era of visual observations, NGC 6907 appeared not as a huge spiral structure overlapping NGC 6908, but as a slightly brighter slightly larger fuzzy spot (the brightest part of the galaxy) a little to the south and west of NGC 6908 (and hence, "preceding"). The position precesses to RA 20 25 07.7, Dec -24 48 01, less than 0.3 arcmin west of the galaxy, but even without that good agreement the description of its relationship to NGC 6907 would make the identification of NGC 6908 certain. Based on a recessional velocity of 3060 km/sec, NGC 6908 is about 145 million light years away. Given that and its apparent size of 0.3 by 0.1 arcmin, it is about 12 thousand light years across. NGC 6908 is superimposed on the northeastern arm of NGC 6907, and must lie in front of it. The two galaxies' recessional velocities are nearly the same, which may mean that they are at nearly the same distance, and gravitationally interacting; if so, that may explain the slightly distorted shape of NGC 6907. However, there is no sign of gravitational effects on NGC 6908, so the galaxies may be several million light years apart, and simply an optical double.

2.2 by 1.1 arcmin

(10 arcmin wide?)

1.7 by 1.1 arcmin

1.4 by 1.1 arcmin

(10 arcmin wide?)

3.0 by 3.0 arcmin

1.5 by 0.9 arcmin

1.8 by 1.2 arcmin

1.4 by 1.0 arcmin

0.9 by 0.7 arcmin

1.6 by 1.2 arcmin

1.8 by 1.5 arcmin

0.9 by 0.2 arcmin

1.3 by 1.1 arcmin

2.6 by 1.3 arcmin

The first IC lists a corrected RA (per Ormond Stone) of 20 24 57. 2.0 by 1.7 arcmin

4.4 by 1.1 arcmin

Based on a recessional velocity of 5880 km/sec, NGC 6926 is about 275 million light years away. Given that and its 1.9 by 1.3 arcmin apparent size, it is about 150 thousand light years across. NED states that it is in a group with NGC 6929 and PGC 64910 (among others?), and a member of a pair with an unnamed member of that group; their gravitational interaction is perhaps responsible for its active core, which classifies it as a Seyfert galaxy (type Sy2). (Note: An Internet search for NGC 6926 can lead to a nice image of a spiral galaxy at santacruzoptics; but that is actually a mislabeled image of NGC 6946.)

Based on a recessional velocity of 5950 km/sec, PGC 64910 is about 275 million light years away. Given that and its 1.7 by 1.5 arcmin apparent size, it is about 135 thousand light years across. It is listed by NED as a member of a group with NGC 6926 and 6929 (among others?).

0.5 by 0.2 arcmin

0.3 by 0.1 arcmin (? unless rounded off, does not agree with type ?)

2.1 by 0.6 arcmin

Based on a recessional velocity of 6175 km/sec, NGC 6929 is about 290 million light years away. Given that and its 0.8 by 0.7 arcmin apparent size, it is about 65 thousand light years across. It is listed by NED as a member of a group with NGC 6926 and PGC 64910 (and others?), and as a pair member with one of the group members (but which is left unstated).

1.2 by 0.5 arcmin

The second IC lists a corrected RA (per Bigourdan and Howe) of 20 26 01. 1.0 by 0.4 arcmin

2.2 by 1.6 arcmin

NGC erratum: delete star (meaning, do not see notes)

About 55 thousand light years from the Sun, and 120 light years in diameter (= 7 arcmin?)

2.1 by 1.8 arcmin

The first IC lists a corrected RA (per Ormond Stone) of 20 26 26. The second IC has an extended note: "Ormond Stone's place is RA 20 26 26, NPD 115 53.4, while Howe gives RA 20 27 36, NPD 115 45.6. There are two comparison stars with exactly these differences, C.D. 14864 and 14877. Ormond Stone says he used the former, but Howe's NPD agrees with that of Leavenworth, whose P.D.'s are always right within about a minute". (This seems to imply that Stone used the wrong comparison star, and Howe's position is more accurate.) 1.8 by 1.0 arcmin

2.5 by 2.1 arcmin

(8 arcmin wide?)

(10 arcmin wide?)

(25 arcmin wide?)

2.0 by 1.4 arcmin

2.1 by 1.6 arcmin

4.0 by 2.2 arcmin

1.5 by 0.6 arcmin

0.9 by 0.7 arcmin

1.6 by 0.8 arcmin

NGC 6946 is a spectacular galaxy, but relatively faint for its large size, because it lies nearly in the plane of the Milky Way, and is considerably obscured and reddened by the dust in the plane of our galaxy. However, as a Seyfert galaxy (type Sy2), it does have a bright core. One of the Milky Way's nearest neighbors, the galaxy has an insignificant Hubble expansion velocity, so its "recessional" velocity of 40 km/sec gives no indication of its distance. Redshift-independent distance estimates range from 18 to 40 million light years, with a general consensus more in the range of 20 to 25 million light years. Given that, its 11.5 by 9.8 arcmin apparent size implies that the galaxy is about 75 thousand light years across.

1.6 by 1.0 arcmin

2.2 by 1.0 arcmin

1.4 by 1.2 arcmin