Warning: This observing report will be rather lengthy and of no interest to anyone except fans of globular clusters. It's my report of an observing session last Tuesday, May 22, at Cottonwood Springs, Joshua Tree National Park, California, one of my occasional dark sky observing sites. At such occasions I usually seek out open clusters, but my sky atlas told me that there are few or no such objects between the milky way's northern winter arm (Auriga, Taurus, Gemini, Orion, Monoceros, etc.) and its summer arm, and I had no intention of spending the wee hours of the morning at this location. Moreover, the multitude of galaxies in our evening skies in Spring would be beyond the grasp of my equipment on this evening when the sky was washed in the light of the 5-day old moon -- except for bright M51, M81 and M82, which I dutifully viewed before the evening was over. So my observing agenda consisted of a list of globular clusters that lie in our northern hemisphere skies east of the winter's milky way and west of "globularland" in Ophiuchus, Scorpius and Sagittarius.
My usual practice is to list the objects I plan to view, note down my impressions of them, and afterwards compare what I saw with the comments in the observing handbooks in my library. I viewed these globulars at 102x through a 20 mm eyepiece in an 8-inch SCT.
***M68 in Hydra struck me as a rather shapeless globular cluster, in the southerly reaches of which I detected a few individual stars and which seemed somewhat remarkable to me for not displaying a core region that was distinctly brighter than its outer reaches. My impression was consistent with the descriptions of M68 as seen in lower aperture instruments as a "weakly concentrated circular glow" (Luginbuhl & Skiff) and as a "faint, large oval haze" (Webb Society handbook, vol. 3).
***NGC 5694 in Hydra appeared to me as a nondescipt fuzzball of approximately the same magnitude as two stars that lie just southwest of it in the same field of view. Luginbuhl & Skiff said of this cluster seen through a 25-cm (10-inch) instrument that "The cluster is 2' diameter and shows no resolution," and that is how I also saw it. Later I found out that NGC 5694 is one of the Herschel 400 objects; and that it is #66 in Patrick Moore's Caldwell list, and a photo of it on page 263 of O'Meara's book about Caldwell objects tends to confirm my visual impression.
***M3 in Canes Venatici is my nostalgic favorite, because it was the first bright globular cluster I had ever seen. On this occasion it was a brilliant sight, even in this moonlit sky, showing a bright core that appeared almost three-dimensional and revealed extensive granularity, surrounded by a halo of unresolved members.
***NGC 4147 in Coma Berenices (also a Herschel 400 object) is a small, tight fuzzball that seemed somewhat oval in shape to me, with its east-west dimension somewhat exceeding its north-south dimension. My impression was consistent with the Webb Society observer's description of NGC 4147 as a "Very faint, small oval; elusive object." But I did not see it as having a bright core or nucleus as did other Webb Society observers and Luginbuhl & Skiff.
***M53 in Coma Berenices showed me a bright core with a halo of unresolved stars extending mainly in the north-south directions, and I did not observe any evidence of individual stars or granularity, nor of any strings of stars leading away from the cluster. Luginbuhl & Skiff seems to confirm my impression of the non-circular halo in stating that most of the "outliers" are on the NW and SE.
***NGC 5053 in Coma Berenices and NGC 5466 (a Hershel 400 object) in Boötes: to my disappointment, I could not find these globulars this night, although I had previously viewed NGC 5053.
***NGC 5634 in Virgo was a bit of a challenge. I saw an east-west string of three stars, and just northwest of the easternmost of them a small rather shapeless glow that I would have taken for an out-of-focus star but for the fact that the other stars in the field of view were in good focus. This was evidently NGC 5634 which Luginbuhl & Skiff says "is set among three mag. 8.5 - 11 stars, the brightest located only 1'.3 ESE of the center." The cluster is referred to as compact and unresolved in my observing handbooks.
***M5 in Serpens Cauda was a brilliant apparition, bigger and brighter than M3, with a granulated three-dimensional appearing core, several strings of outlying stars, and an extensive halo that made the cluster appear to be stretching away from the globular or spherical shape. This last feature is noted in Luginbuhl & Skiff, which says: "More outliers spread to the S, W, and N than to the E, giving the halo an asymmetric form."
***M13 in Hercules was, by visual dimension, easily the largest of the globulars I viewed this night, but interestingly it consisted mainly of its brilliant granulated core, without the extensive halo exhibited by M5 and M3. I saw many individual stars and strings of stars in and around M13.
***NGC 6229 in Hercules appeared to me as a small round fuzzball, which, however, showed me a distinct halo surrounding a brighter core. This feature was not mentioned by Luginbuhl & Skiff, but the Webb Society observer with a 16½-inch instrument noted that the central area appeared "almost stellar x70."
***M92 in Hercules was a good, bright globular cluster, wtih an extensive halo around a bright core, which I likened to a dimmer version of M5.
By the time I had completed my observations of these objects, the top of Scorpius (with Jupiter) had risen in the southeast, and all of Ophiuchus was now above the eastern horizon. To complete my observations of globulars, I took in M12, M10 and M14 in Ophiuchus, all of which were impressive as they usually are in dark skies (even though the bright moon was still well above the western horizon). I then peeked at M4 in Scorpius, and noted that this was surely the most chaotic of the globulars, appearing as a rather shapeless halo of stars, a large but relatively dim expanse of nebulous fuzz, although its appearance on this occasion may have been adversely affected by the fact that it was still fairly low on the horizon when I looked at it and was preparing to depart.