No. 650. This object lies about 3 degrees north of the star μ Leonis, the most northern of the bright stars in the well-known “Sickle,” and is thus described by Sir John Herschel: “A star 12th magnitude with an extremely faint nebulous atmosphere about 10″ to 12″. It is between a star 8-9 magnitude north preceding, and one 10th magnitude south following, neither of which are so affected. A curious object.”
No. 1558. Messier 53. A little north-east of the star α Comæ Berenices. Described as “a most beautiful highly compressed cluster. Stars very small, 12th ... 20th magnitude, with scattered stars to a considerable distance; irregularly round, but not globular. Comes up to a blaze in the centre; indicating a round mass of pretty equable density. Extremely compressed. A most beautiful object. A mass of close-wedged stars 5′ in diameter; a few 12th magnitude, the rest of the smallest size and innumerable.” Webb says, “Not very bright with 37⁄10 inches; beautiful with 9 inches.” This should be a magnificent object with a very large telescope, like the Lick or Yerkes.
No. 2018. “A more than usually condensed portion of the enormous cluster of the Milky Way. The field has 200 or 300 stars in it at once.” This lies about 2° south-west of the star 6 Aquilæ, which is near the northern edge of the bright spot of Milky Way light in “Sobieski’s Shield”—one of the brightest spots in the sky.
No. 2093. “A most wonderful phenomenon. A very large space 20′ or 30′ broad in Polar Distance, and 1m or 2m in Right Ascension, full of nebula and stars mixed. The nebula is decidedly attached to the stars, and is as decidedly not stellar. It forms irregular lace-work marked out by stars, but some parts are decidedly nebulous, wherein no star can be seen.” Sir John Herschel gives a figure of this curious spot, which he says represents its “general character, but not the minute details of this object, which would be extremely difficult to give with any degree of fidelity.” It lies about 3 degrees west of the bright star ζ Cygni.
Among the numerous curious objects observed by Sir John Herschel during his visit to the Cape of Good Hope, the following may be mentioned:—
h 2534 (H iv. 77). Near τ4 Eridani. Sir John Herschel says, “Attached cometically to a 9th magnitude star which forms its head. It is an exact resemblance to Halley’s comet as seen in a night glass.”... “A complete telescopic comet; a perfect miniature of Halley’s comet, only the tail is rather broader in proportion.”[367]
h 3075. Between γ Monocerotis and γ Canis Majoris. “A very singular nebula, and much like the profile of a bust (head, neck, and shoulders) or a silhouette portrait, very large, pretty well defined, light nearly uniform, about 12′ diameter. In a crowded field of Milky Way stars, many of which are projected on it.”[368]
h 3315 (Dunlop 323). In the Milky Way; about 3° east of the Eta Argûs nebula. Sir John Herschel says, “A glorious cluster of immense magnitude, being at least 2 fields in extent every way. The stars are 8, 9, 10, and 11th magnitudes, but chiefly 10th magnitude, of which there must be at least 200. It is the most brilliant object of the kind I have ever seen” ... “has several elegant double stars, and many orange-coloured stars.”[369] This should form a fine object in even a comparatively small telescope, and may be recommended to observers in the southern hemisphere. A telescope of 3-inches aperture should show it well.
Among astronomical curiosities may be counted “clusters within clusters.” A cluster in Gemini (N.G.C. 2331) has a small group of “six or seven stars close together and well isolated from the rest.”
Lord Rosse describes No. 4511 of Sir John Herschel’s General Catalogue of Nebulæ and Clusters (Phil. Trans., 1864) as “a most gorgeous cluster, stars 12-15 magnitude, full of holes.”[370] His sketch of this cluster shows 3 rings of stars in a line, each ring touching the next on the outside. Sir John Herschel described it as “Cluster; very large; very rich; stars 11-15 magnitude (Harding, 1827),” but says nothing about the rings. This cluster lies about 5 degrees south of δ Cygni.