Based on recessional velocity of 1910 km/sec, about 85 million light years away. Given that and apparent size of 1.3 by 0.7 arcmins, about 30 thousand light years in diameter.

(Historical: The second IC says "RA is 1 minute too small (W.H. was right). 2361 is one of the points of condensation".) NGC 2359 is a bubble-like nebula about 30 light years across and 15 thousand light years away, which is energized by stellar winds blowing away from a Wolf-Rayet star near its center. Such stars are high-mass Main Sequence stars (blue giants) and have very short lifetimes, so they are relatively rare at any given time, since most of them have already died in supernova explosions. Surrounding the bubble are complex bow-shock structures created when the millions of miles per hour stellar wind pushed the expanding bubble of gas into surrounding clouds of gas and dust.

The first IC says "This is probably (William Herschel's) V.21, for which H gave the RA 07 12 02. d'Arrest's RA agrees with Bigourdan's". Also, a second IC note about 2359 states that 2361 is one of the points of condensation in that nebula.

(Historical: the second IC says "About its spectrum see Pickering, A.N. 4089, p.141". Not relevant to a determination of its identification, but perhaps of interest to some readers.) NGC 2392 is a double shell planetary nebula, consisting of a white dwarf (a formerly Sun-like star) surrounded by two regions ejected by the star. The outer "shell" is believed to be a dense, slow-moving (approximately 20 miles per second) structure ejected from the equatorial region of the star when it was a red giant, ten thousand years ago. The gas in the outer region is moving outward at about 20 miles per second. The inner region consists of two elliptical lobes emitted by the polar regions of the star, approximately directly toward and away from us (so that the front lobe mostly obscures the back one). The gas in this lobe is moving much faster (from 60 to 120 miles per second), and is much hotter (3 to 4 million Fahrenheit degrees) than the gas in the outer shell. NGC 2392 is about 3000 light years away. Given that and its apparent size of 0.8 by 0.7 arcmin, it is about 2/3 light year in diameter. This contradicts frequently-quoted estimates of the linear structures in the outer shell being a light year in length, as they can't be larger than the entire nebula. Note: Searching for NGC 2392 in Wikisky brings up the wrong object, galaxy PGC 21128.

Based on recessional velocity of 4525 km/sec, about 200 million light years away. Given that and apparent size of 0.75 by 0.4 arcmin, about 45 thousand light years across.

A cluster of about twenty stars about 1350 light years away. Given that and its apparent size of 12 arcmin, about 5 light years across. The cluster appears to have lost most of its original stars (particularly the lower-mass ones) due to gravitational interactions with non-cluster stars, as it orbited the galaxy over the approximately billion and a half years since its formation. (In the image below, the bright reddish stars near the center are K-type red giants whose characteristics were used to establish the age of the cluster.)

Per Dreyer, NGC 2399 (= Bond (#9, HN 9), 1860 RA 07 22 41, NPD 89 55.6) is one of "two faint nebulae (Auwers 24 & 25), ? very small clusters", the other being NGC 2400 (which see for an image of the two NGC objects). The position precesses to RA 07 29 51.0, Dec -00 12 48, almost dead center on the triplet of stars; so the identification is certain. Note: A Wikisky search for NGC 2399 shows a position close to NGC 2400, and does not indicate any NGC label; so use the coordinates to see the correct triplet.