Let me note at the outset that the Zenit rocket bodies are among the brightest and visually most interesting objects above us. In a message from Bart and Tristan, on October 31, we read: > Subject: Observing Program of the BWGS > 94-074B: had a small acceleration, first Zenit to do so ! Thanks to them for pointing out this interesting fact and also to the unnamed observer whose observations detected this. Following is a brief excerpt from current elements for objects with a dimension of 10.4 meters (thanks to Adam Johnson, TS Kelso, and Ted Molczan for their contributions to these): vulgar formal orbital cat # id # i MM name dimensions ABS mag plane ** 16182U 85 97B 70.99 14.15 C* 1697 r 10.4 3.9 0.0 4.6 A 17590U 87 27B 70.99 14.15 C* 1833 r 10.4 3.9 0.0 4.6 B 17974U 87 41B 71.00 14.16 C* 1844 r 10.4 3.9 0.0 4.6 D 19120U 88 39B 71.00 14.17 C* 1943 r 10.4 3.9 0.0 4.6 C 19650U 88102B 70.99 14.14 C* 1980 r 10.4 3.9 0.0 4.6 A 20625U 90 46B 70.99 14.13 C* 2082 r 10.4 3.9 0.0 4.6 D' 22220U 92 76B 70.99 14.15 C* 2219 r 10.4 3.9 0.0 4.6 E 22285U 92 93B 71.01 14.13 C* 2227 r ***10.4 3.9 0.0 4.6 B 22566U 93 16B 71.00 14.13 C* 2237 r 10.4 3.9 0.0 4.6 C 22803U 93 59B 70.98 14.15 C* 2263 r 10.4 3.9 0.0 4.6 23088U 94 23B 70.99 14.13 C* 2278 r 10.4 3.9 0.0 4.6 E' 23343U 94 74B 97.99 14.70 Resurs 1-3 r 10.4 3.9 0.0 4.6 23405U 94 77B 70.98 14.14 C* 2297 r 10.4 3.9 0.0 4.6 C' 23705U 95 58B 71.01 14.14 C* 2322 r 10.4 3.9 0.0 4.6 B' ** As identified by Russell Eberst and Bjoern Gimle, and augmented by me. (This classification is somewhat different than Nick Johnson and David Rodvold adopt in 1991-1992, Europe & Asia in Space. They have 2219 replacing 1943; I find the r/b's have different RAANs.) *** The launch size indicated by these dimensions may be suspected because this object experienced an explosion (see Mike McCants' analysis of the elsets of the many fragments). Some of us have watched the monotonic increase of some of these objects for a considerable time. Leaving aside the vulgar name, which presumably reflects the intended purpose of the payloads, we see that Resurs 1-3 r distinguishes itself in inclination and mean motion, as well as flashing history. As an observer, I have been impressed with the brightness of Resurs 1-3 r, which may likely be strongly influenced by its lower height and shorter range, which in this table is reflected in the faster MM. I know (thanks to Allen Thomson, and see also his analyses of the very peculiar orbital evolution of the 71 degree objects) that one of the Zenits, perhaps it was C* 1714, suffered a sad fate; but except for that, does this table contain all the Zenits? I think I recently read of a short-lived Zenit, perhaps in Jonathan's Space Report or on SeeSat-L. As a personal note, let me say that I well remember watching C* 2082 r when its period was perhaps 8 or 12 seconds and thinking "Boy, this junk sure puts on quite a show". A photo of a Zenit, I think it was C* 1980 r, appeared a year or so ago in Sky & Telescope magazine, accompanying an article by Gerald Ouellette. Here is a similar table for the payloads: 16181U 85 97A 70.96 14.1271 C* 1697 6.0 2.0 0.0 5.9 17589U 87 27A 70.92 14.1252 C* 1833 3.0 0.0 0.0 6.0 17973U 87 41A 70.88 14.1281 C* 1844 3.0 0.0 0.0 6.0 19119U 88 39A 71.00 14.1367 C* 1943 3.0 0.0 0.0 6.0 19649U 88102A 71.00 14.1341 C* 1980 3.0 0.0 0.0 6.0 20624U 90 46A 71.04 14.1287 C* 2082 3.0 0.0 0.0 6.0 22219U 92 76A 71.01 14.1233 C* 2219 3.0 0.0 0.0 6.0 22284U 92 93A 71.00 14.1229 C* 2227 6.0 2.0 0.0 5.9 22565U 93 16A 70.99 14.1235 C* 2237 6.0 2.0 0.0 5.9 22802U 93 59A 71.01 14.1237 C* 2263 6.0 2.0 0.0 5.9 23087U 94 23A 71.00 14.1215 C* 2278 6.0 2.0 0.0 5.9 23342U 94 74A 98.00 14.6978 Resurs 1-3 5.0 1.5 0.0 6.5 23404U 94 77A 71.04 14.1248 C* 2297 6.0 2.0 0.0 5.9 23704U 95 58A 71.02 14.1255 C* 2322 6.0 2.0 0.0 5.9 If we look at the MMs of the C* 1933 family, we see a strong, but not invariant, monotonic increase in the MM as the object ages (i.e., the later objects have smaller MMs). Even discarding Resurs 1-3, we see no such secular trend here, or hardly any. This is consistent with Allen Thomson's analysis. Ted, (or Mike, from the observational side), do you have strong evidence to divide these payloads into rectangular and spherical groups, as the sizes indicate? I provide an elset for the latest rocket body: C* 2322 r 10.4 3.9 0.0 4.6 1 23705U 95058B 95310.21715407 -.00000047 +00000-0 +00000-0 0 00273 2 23705 071.0138 19.7952 0007144 112.3514 247.8391 14.14145728000769 Exercises for the reader (all available from the SeeSat-L archive): Mike McCants' observed absolute magnitudes for these objects PPAS flash periods for these objects Cheers. Walter I. Nissen, Jr., CDP 216-243-4980 dk058@cleveland.freenet.edu --- First, do no harm.