A pair of papers by Mackey and Gilmore in the 1 Jan 2003 issue of the "Monthly Notices of the Royal Astronomical Society" contain surface-brightness profiles for about 60 mostly bright clusters in the Magellanic Clouds. The profiles are calibrated nearly to the standard V system so that isophotal diameters can be derived. The results are based on archive HST images, and so avoid problems with crowding that would appear on data from ground-based plates or CCD images. The data are published (in the journal and at the authors' Web site) only as the graphical radial profiles, so tabular data are not available. I thus read off the curves at the muV 22 and 25/square arcsec isophotes, and the results are listed below. These are diameters not radii (the log radii were anti-logged and multiplied by 2). The muV = 22 isophote corresponds to the bright bulk of the cluster, though because of the sometimes bright backgrounds of the Clouds, this may be about the greatest extent you'll see visually. The muV = 25 isophote, available for most of the clusters, conforms to 'standard' usage for galaxy dimensions, and less formally for Galactic globular clusters. You need a fairly large telescope (60+cm) at a true-dark site to see to this surface-brightness level visually. Notice that the mu25 diameter is very approximately 3x the mu22 diameter, though there is considerable variation. I show the diameters in arcseconds, though I debated rounding them to simple 0'.1 precision. The uncertainty in reading off the plots is something like +/- 3" to 5". Frankly, I would do the rounding if they're to be quoted in publication. You are also free to make your own better estimates; the data are here: http://www.ast.cam.ac.uk/STELLARPOPS/LMC_clusters A by-product of the radial profiles is a accurate assessment of the position of the cluster centers (or more specifically the central surface brightness peak). The authors' algorithm is claimed to be repeatable at the ~1" level, which is how they're given in the paper and copied below. In any case, none of the positions is far from what's already published. \Brian ------------------------------------------------------------------------------- Isophotal diameters for Magellanic Cloud clusters version: 8 Jan 2003 sources: 2003MNRAS.338...85M 2003MNRAS.338..120M diameter(") Name RA (J2000) Dec mu22 mu25 NGC 1466 3 44 32.9 -71 40 13 64 155 NGC 1651 4 37 31.1 -70 35 02 56 209 NGC 1711 4 50 37.3 -69 59 04 73 200 NGC 1718 4 52 25.6 -67 03 06 55 191 NGC 1754 4 54 18.9 -70 26 31 44 138 NGC 1777 4 55 48.9 -74 17 03 59 191 NGC 1786 4 59 07.9 -67 44 45 60 163 NGC 1805 5 02 21.8 -66 06 42 49 132 NGC 1818 5 04 13.8 -66 26 02 80 214 NGC 1831 5 06 17.4 -64 55 11 100 NGC 1835 5 05 06.7 -69 24 15 63 163 NGC 1841 4 45 23.9 -83 59 56 45 NGC 1847 5 07 07.7 -68 58 17 80 NGC 1850 5 08 41.2 -68 45 31 209 NGC 1856 5 09 31.5 -69 07 46 155 NGC 1860 5 10 38.9 -68 45 12 46 166 NGC 1866 5 13 38.9 -65 27 52 100 NGC 1868 5 14 36.2 -63 57 14 54 135 NGC 1898 5 16 42.4 -69 39 25 60 219 NGC 1916 5 18 37.5 -69 24 25 65 182 NGC 1984 5 27 40.8 -69 08 05 33 117 NGC 2004 5 30 40.9 -67 17 09 96 NGC 2005 5 30 10.3 -69 45 09 49 143 NGC 2011 5 32 19.6 -67 31 14 35 126 NGC 2019 5 31 56.6 -70 09 33 56 170 NGC 2031 5 33 41.1 -70 59 13 83 NGC 2100 5 42 08.6 -69 12 44 100 NGC 2121 5 48 11.6 -71 28 51 82 NGC 2136 5 52 58.0 -69 29 36 71 155 NGC 2153 5 57 51.2 -66 23 58 23 67 NGC 2155 5 58 33.3 -65 28 35 53 172 NGC 2156 5 57 49.7 -68 27 41 41 119 NGC 2157 5 57 32.4 -69 11 49 79 187 NGC 2159 5 58 03.0 -68 37 27 46 129 NGC 2162 6 00 30.4 -63 43 19 42 126 NGC 2164 5 58 55.9 -68 31 00 62 166 NGC 2172 6 00 06.4 -68 38 15 51 121 NGC 2173 5 57 58.5 -72 58 40 53 191 NGC 2193 6 06 17.0 -65 05 54 32 105 NGC 2209 6 08 34.8 -73 50 12 159 NGC 2210 6 11 31.5 -69 07 17 60 134 NGC 2213 6 10 42.2 -71 31 46 43 121 NGC 2214 6 12 55.8 -68 15 38 81 NGC 2231 6 20 42.7 -67 31 10 38 166 NGC 2249 6 25 49.8 -68 55 13 48 121 NGC 2257 6 30 12.1 -64 19 42 66 172 SL 663 5 42 28.8 -65 21 44 166 SL 842 6 08 14.9 -62 59 15 23 80 SL 855 6 10 53.7 -65 02 30 103 Hodge 4 5 32 25.2 -64 44 11 49 207 = SL 556 Hodge 11 6 14 22.3 -69 50 50 63 214 = SL 868 Hodge 14 5 28 39.3 -73 37 49 27 100 = SL 506 SMC NGC 121 0 26 48.8 -71 32 12 66 166 NGC 152 0 32 55.7 -73 07 01 49 214 NGC 176 0 35 59.2 -73 09 59 30 100 NGC 330 0 56 18.0 -72 27 47 100 NGC 339 0 57 47.3 -74 28 22 61 163 NGC 361 1 02 11.6 -71 36 21 62 NGC 411 1 07 56.0 -71 46 03 53 163 NGC 416 1 07 59.1 -72 21 12 60 135 NGC 458 1 14 52.1 -71 33 05 65 164 Kron 3 0 24 45.8 -72 47 38 76