Below is a tabular display of the Iridial constellation, principally to facilitate visual observation. At the top of the table you will find a rectangle of 66 objects which form the working array. A total of 90 objects have been orbited, including 2 Sim objects which are (always?) faint because they lack the mirror-like surfaces of the operating Iridia. The 66 objects are in 6 regular undecagons (11-sided regular polygons). The planes containing objects going in the same direction, ascending or descending, are separated by about 31.58 degrees, though this is not indicated in the table. The planes in which objects go in opposite directions are separated by about 22.10 degrees. In the table, the six planes are designated P0 thru P5 and these correspond to planes numbered 1 thru 6 in some other sources. The Earth carries you (unless you are reading this from a spacecraft or are near one of the poles) under the planes in consecutive order beginning with P0 and ending with P5. All of these objects are going the same direction, ascending or descending. Then the direction reverses and you go under the planes again in the same order. The objects within a given plane are numbered 0 thru 9 and A, consecutively, in the order in which they pass by. The table also shows the number used by OIG for the object. Note that some of these numbers from OIG are the same as those used by others for different objects, thus making them all but useless to identify a particular object. However the P-designations are not ambiguous, to the very best of my knowledge. Thus, if Ir P50 39 has just passed by, then in about 9.1 minutes, Ir P51 80 will pass by going the same direction and a little bit to the West of the track of Ir P50. With the P-designations, this deduction is simple. Best of luck using the numbers you find elsewhere. Fortunately, the table allows you to translate. Within the rectangle, an R follows the P-number of an object which replaces an object which formerly occupied the same position in the array. This practice prevents ambiguity. The remaining 90 - 2 - 66 = 22 objects are shown below the rectangle. Some objects may be on standby, to be used in the event one of the operating objects fails. These are designated with B, C, D, etc. Some objects have failed and are flashing, apparently because they are tumbling. These are designated S, T, U, etc. The objects which have moved out of plane are shown in the table offset to the left, with arrows marking some which have moved substantially. The full table is pretty long to post here very often, so just the most interesting part is shown below. If you see behavior inconsistent with this explanation, your report will be welcome here, and when confirmed, will indicate a need to update the table. Thanks are due to many people for information and inspiration, Rob Matson, Mike McCants, Ron Lee, Alan Pickup, John Gardner come prominently to mind, and to Jim Varney for publicly expressing his appreciation. Cheers. Walter Nissen wnissen@tfn.net -81.8637, 41.3735, 256m elevation --- P00 64 P10 24* P20 32 P30 5 P40 10* P50 39 P01 65 P11 47 P21 33 P31 6 P41 9* P51 80 P02 66 P12R 11A P22 57 P32 7 P42 52* P52 17 P03 67 P13 49 P23 58 P33 8 P43 12 P53 15 P04 68 P14 26 P24 59 P34 4 P44 13 P54 81 P05 74 P15R 3 P25 60 P35 35* P45R 83 P55 38 P06 72 P16 22 P26 55 P36 61 P46 16 P56 41 P07R 75 P17 23 P27 28 P37 19 P47 53* P57 43 P08 70 P18 76 P28 29 P38 34 P48 56 P58 20* P09 62 P19 25 P29 30 P39 37* P49 50* P59 42 P0A 63 P1A 45 P2A 31 P3A 36 P4A 54* P5A 40 P0 C 73 P1 B 69 P3 B 51 P4 B 86 P5 B 77 P0 D 14A P1 D 20A P4 C 84 P5 C 82 P0 E 21A P1 S 46* P4 S 11 P5 S 18* P1 T 71 P4 T 14 P5 T 44 P1 U 48 P4 U 85 P5 U 21 <------< P2 S 27 <---< P5 V 79 <-------------< P4 ?? 2 <-----------------< * numbers have been confused, resolution uncertain ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html