THE ASTRONOMER Electronic Circular No 537 1991 July 07 11.01UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP, England. Telephone: (0256)471074 Int:+44256471074 Telex: 9312111261 Answerback: TA G JANET BOXES: GMH at UK.AC.CAM.ASTRONOMY.STARLINK or GUYH at UK.AC.SUSSEX.CLUSTER TELECOM GOLD: 10074:MIK2885 PRESTEL 256471074 ------------------------------------------------------------------- PERIODIC COMET MACHHOLZ This comet was found by Don Machholz on 1986 May 12 and designated Comet (1986e) [IAUC 4214]. Subsequently S.Nakano produced elements on IAUC 4223 confirming that it was of short-period. According to the International Comet Quarterly 1991 Handbook this comet, which has not so far been recovered in 1991, could reach mag 2 although at an elongation of about 4 degrees! However there remains a possibility that this comet might be recovered during July or August, and perhaps even VISUALLY. The following elements have been downloaded from the IAU Computer: T 1991 July 22.0127 E.T. w 14.52911 ) e 0.95836920 O 93.82273 ) 1950.0 q 0.1255478 A.U. i 60.14704 ) Source: MPC14748 Positions are geocentric m = 13.0 + 5.0 log R + 12.0 log r Ephemeris by Hurst using a program by N.James. The magnitude predictions are very uncertain: Date R.A. (1950) Dec. R r Elong Mag. Motion h m o ' (AU) (AU) o "/hr P.A. 1991 July 7.00 5 53.24 -5 38.0 0.924 0.554 32.7 9.7 346 49 8.00 6 0.24 -4 6.8 0.932 0.527 31.0 9.5 347 49 9.00 6 7.19 -2 34.3 0.941 0.499 29.2 9.2 349 48 10.00 6 14.10 -1 0.3 0.952 0.470 27.4 9.0 351 48 11.00 6 20.99 +0 35.3 0.964 0.441 25.6 8.7 353 47 12.00 6 27.88 +2 12.6 0.977 0.411 23.7 8.3 356 46 13.00 6 34.79 +3 51.9 0.991 0.381 21.8 7.9 361 46 14.00 6 41.76 +5 33.6 1.006 0.349 19.9 7.5 367 45 15.00 6 48.84 +7 18.3 1.023 0.317 17.9 7.1 376 45 16.00 6 56.11 +9 6.7 1.041 0.285 15.9 6.5 388 45 17.00 7 3.66 +10 59.8 1.060 0.252 13.7 5.9 405 45 18.00 7 11.65 +12 59.1 1.079 0.218 11.5 5.2 430 45 19.00 7 20.33 +15 6.2 1.099 0.186 9.1 4.4 464 45 20.00 7 30.05 +17 22.5 1.117 0.157 6.5 3.6 510 46 21.00 7 41.28 +19 47.1 1.130 0.134 3.8 2.8 561 49 22.00 7 54.31 +22 11.7 1.134 0.126 2.3 2.5 593 54 23.00 8 8.70 +24 19.7 1.126 0.134 4.1 2.8 581 60 24.00 8 23.50 +25 59.9 1.109 0.156 6.7 3.5 544 66 25.00 8 38.15 +27 12.9 1.088 0.185 9.3 4.4 508 72 26.00 8 52.49 +28 4.2 1.066 0.217 11.7 5.2 482 77 27.00 9 6.56 +28 38.4 1.045 0.250 13.9 5.9 464 81 28.00 9 20.39 +28 59.0 1.026 0.283 16.0 6.5 452 85 29.00 9 34.03 +29 8.0 1.009 0.316 18.0 7.0 444 89 30.00 9 47.48 +29 7.2 0.994 0.348 19.9 7.5 438 92 31.00 10 0.74 +28 57.5 0.981 0.379 21.8 7.9 433 94 1991 Aug 1.00 10 13.80 +28 40.0 0.970 0.410 23.7 8.3 429 97 2.00 10 26.62 +28 15.3 0.960 0.440 25.5 8.6 426 99 3.00 10 39.19 +27 44.3 0.953 0.469 27.3 8.9 422 102 4.00 10 51.48 +27 7.4 0.948 0.498 29.1 9.2 417 104 5.00 11 3.46 +26 25.5 0.944 0.526 30.9 9.5 413 105 6.00 11 15.11 +25 39.0 0.943 0.553 32.6 9.8 407 107 7.00 11 26.42 +24 48.6 0.943 0.580 34.2 10.0 401 109 8.00 11 37.36 +23 55.0 0.944 0.606 35.8 10.3 394 110 9.00 11 47.93 +22 58.6 0.948 0.632 37.4 10.5 387 112 10.00 11 58.13 +22 0.1 0.952 0.657 38.9 10.7 379 113 11.00 12 7.94 +20 60.0 0.958 0.682 40.4 10.9 370 114 12.00 12 17.38 +19 58.6 0.966 0.707 41.8 11.1 361 115 Guy M Hurst