U 248
17:20 to 17:52
+6° to -6°
Oph

FEATURED OBJECTS: Cr 350, NGC 6366, NGC 6402 (Ben 97), NGC 6426, IC 4665.

Cr 350

RA 17:48:11
Dec +01° 18.0'
Open cluster

Steve Coe, using a 13” f/5.6, notes: “ Bright, large, scattered, 32 stars counted at 60X with several nice chains of stars and some pairs.”

11x80: Suburban skies: Exceedingly boring cluster. Just 9.5mag stars, 12 of them. No shape; some are in a ragged line roughly N-S. Dark exurban skies: Lies due south of Gamma Oph. While sweeping around here I noticed this patch of sky. About a dozen small stars are scattered over a degree or so, making a distinct faint grouping. Not at all clear, no boundary. The region around 67, 68 70 Oph and about 2 degrees further east fills the 5deg binoc view with pB stars from side to side, like a sparse scattered cluster. Looks like Pleiades seen with high power. [AS]

NGC 6366
GCL-65
RA 17:27:42
Dec -05° 04.5'
Globular cluster

This globular cluster lies a quarter of a degree east of 47 Ophiuchi, and Walter Scott Houston reports that it appears only 3' across in his 4” refractor, and about 5' across in the 20” Clark refractor at Van Vleck Observatory, Connecticut. Houston notes that in the 20-inch “it appears more like a highly compressed open cluster.”

Tom Lorenzin, in the e-version of “1000+ The Amateur Astronomers’ Field Guide to Deep Sky Observing”, notes: “12M; 4' diameter; fairly large, faint and unresolved with little brighter center; 11 and 12M stars to NW; 12 and 13M stars superimposed a few seconds N of core; 10' due E of 5M 47 OPH.”

Steve Coe, using a 13” f/5.6, notes: “ Faint, large, round, not brighter in the middle at 135X. I counted 11 stars when I raised the power to 220X on this low surface brightness globular. It is somewhat strange for a globular in that it is not compressed at all. It looks like a pretty faint open cluster with several brighter members. When a friend looked into the eyepiece, he said it looked like oatmeal. I agreed.”

11x80: Dark exurban skies: East of 47 Oph. This globular looks very much like an internal reflection of the reasonably bright 47 Oph near. Needs averted vision to show it clearly as a vague hazy image. Suburban skies: Very faint cluster, with 47 Oph due west. A small star precedes the cluster, between cluster and star. Requires attention and a star chart to locate. Not casually sene. One of the faintest clusters I’ve yet seen. (suburban skies) [AS]

NGC 6402
Bennett 97
Messier 14, GCL-72
RA 17:37:36
Dec -03° 15.0'
Globular cluster

In the Philosophical Transactions, 1814, William Herschel described it as “like an extremely bright, easily resolvable round nebula; but with a power of 300 I can see the stars of it. It resembles the 10th of the Connoissance des Temps, which probably would put on the same appearance as this, were it removed half its distance farther from us. The stars are much condensed in the middle.” In the Philosophical Transactions, 1818, William Herschel wrote: “1783, 7 feet telescope. with 227 power, therte is a strong suspicion of its consisting of stars. 1783, 1784, 1791, 1799, 20 feet telescope. Extremely bright, round, easily resolvable; with 300 power I can see the stars. The heavens are pretty rich in stars of a certain size, but they are larger than those in the cluster, and easily to be distinguished from them. The cluster is considerably behind the scattered stars, as some of them are projected upon it.”

h: “a most beautiful and delicate globular cluster, not vB, but of the finest star-dust; all well resolved, especially with the left eye; vgmbM, diam in RA = 15 seconds; excessively rich. All the stars = and 15 or 16m.”

Walter Scott Houston comments that his low-power 5” refractor shows it as “little more than a soft patchy glow.”

Bill Johnson of Rialto, California, used an 8-inch Newtonian to observe the cluster, and described it as “somewhat bright but seems to have a low surface brightness. I noticed some resolution around the edges.” He used high to medium powers to observe it.

John Bortle (Webb Society Quarterly Journal, January 1976) using 10x50 binoculars, estimates the visual magnitude as 7.9.

Tom Lorenzin, in the e-version of “1000+ The Amateur Astronomers’ Field Guide to Deep Sky Observing”, notes: “9M; 6' diameter; largely unresolved; 13.5M thru 14M stars resolved on good night; not very condensed in center; use high-x.”

Donald J. Ware:”This object yielded the least amount of detail in my telescope. It is about 8' in diameter, with resolution hinted at the edges at 179X. Little detail other than a granular core was noted.”

Steve Coe, using a 13” f/5.6, notes: “Very bright, very large, round, extremely rich, extremely compressed at 165X. I estimated 200 stars by counting 50 in one quadrant. This beautiful globular shows off an explosion of faint stars when I use averted vision.”

11x80: Quite an easy target, this neat broad-centred globular lies in a somewhat sparse field of equally bright stars. Around 8th magnitude. [AS]

NGC 6426
GCL-76
RA 17:44:53
Dec +03° 10.7'
Globular cluster

Discovered in 1786 by William Herschel (H II-587) with an 18.7-inch f/13 speculum telescope. He called it “F, cL, iF.”

Tom Lorenzin, in the e-version of “1000+ The Amateur Astronomers’ Field Guide to Deep Sky Observing”, notes: “12M; 2' diameter; small and faint with little brighter center; unresolved.”

Steve Coe, using a 13” f/5.6, notes: “Pretty faint, pretty large, elongated 1.5 X 1 in PA 25, somewhat brighter in the middle, 10 stars resolved at 100X from Cherry Rd. This a low surface brightness object.”

IC 4665
Mel 179, Cr 349
RA 17:46:12
Dec +05° 43.0'
Open cluster

Harrington notes that this cluster, although not as rich as other clusters, "stands out surprisingly well thanks to its spartan surroundings. Your finderscope or binoculars will show about 10 stars there, while a 6- to 8-inch telescope increases this number threefold ... high magnifications will ferret out a trio of double stars near the middle of the group."

Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: “6M; 1 degree diameter! very large and sparse; 20-plus 7M members; visible with the naked eye; great binocular object.”

IAAC contribution, Lew Gramer: 7x50 binoculars; A pretty grouping of 10 stars, mags 7 to 10, which formed a tiny "Grus-like" or lambda shaped asterism, pointing due N. IC4665 was VERY easily found, just NE of the E "shoulder star" (beta) of Oph. An intriguing and - I suspect - oft overlooked binocular target!

Steve Coe, using a 13” f/5.6, notes: “ is a very large open cluster that is scattered over at least one degree of sky. It barely fits in the 18" with a 2" Giant Erfle eyepiece. Even so, the cluster aspect is lost and there are just 40 pretty bright stars in the field. My best view of this cluster is with an 8" f/4.5 at 25X. The brighter cluster members are obvious and there are about 100 dimmer members. The field contains many nice chains of stars and several wide double stars. From a dark Arizona site the cluster is naked eye and my 10 X 50 binoculars provide a nice view.”

11x80: Exurban skies: Wonderful! Naked eye object, which shows a roundish fuzzy globular-like glow. Binoculars show a scattered cluster, distinctly spread out but still forming a whole. Look for the Q of about 20 stars. Neat! Dark exurban skies: A very neat little cluster, lying in a rich field. It is scattered -- difficult to get its full extent. The orange-yellow Beta Oph lies to the south-west. I see here a loop of nine stars with a little tail of three stars leading off to the northwest, just like the capital letter Q. And then smack in the middle of this loop sits another little star. A neat little grouping. Pronounced. Reminds me somewhat of the Beehive. (exurban skies) [AS]