Faint star clusters, mostly discovered on Palomar Sky Survey plates, have been reported by several writers. 1 ' 2 ' 3 RRLyrae variables have been found in four, 4 ' 5 ' 6 » 12 namely, Abell 3, 5, 12, and 13, and two long-period variables (P > 130 a ) have been found in Abell 4. 4,6 The variable-star content, high galactic latitudes, and (for Abell 3 and 4) the color-magnitude diagrams 4 suggest that many of these objects are globular clusters.A study of them might reveal possible differences between them and the globular clusters nearer the galactic center.These notes give preliminary results of a variable-star search in some of these clusters, mainly with the Lick 120-inch reflector.Cluster profiles derived from star counts are also given.Abell 1 (l u -130°.0,b 11 -+19°.l).-About 100 stars, mostly between magnitude 20 and 22, were found on a 60-minute exposure plate taken with the 120-inch telescope on Kodak 103a-O emulsion through a Schott GG 13 filter.Since many galaxies are seen in the field, the absorption is unlikely to be large.No variables were found in a comparison of seven Lick plates and five plates obtained by A. R. Sandage with the Palomar 200-inch telescope.Shakhbasian 1 (l 11 = 176°.3, b 11 -+62°.6 ).-Shakhbasian 3 discovered this object in the Palomar atlas and considered it to be a faint cluster at a distance of 130 kpc.Plates taken with the 48-inch Asiago reflector showed 15 to 20 faint stellar images in an area of L5 diameter.Exposures in both the blue and the visual with the 120-inch reflector did not sensibly increase the number of images, some of which were seen to be galaxies and not * Contributions from the Lick Observatory, No. 138.f Morrison research associate, Lick Observatory, 1961.
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Kinman et al. (1962) studied this question.