THE ASTRONOMER Electronic Circular No 623 1992 April 2 20.25UT Ed:Guy M Hurst, 16,Westminster Close, Kempshott Rise, Basingstoke, Hants, RG22 4PP,England. Telephone/FAX(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 ------------------------------------------------------------------- COMET TANAKA-MACHHOLZ (1992d) Following our request for confirmation issued earlier today the following announcement by Brian Marsden has now appeared in IAUCs: "On Mar. 31 D. Machholz reported his discovery of a probable comet, the slight change detected during his 35-min visual observation indicating a daily motion of up to perhaps 1 deg. This suggested possible identity with a cometary object reported by Zenichi Tanaka to the Japanese National Astronomical Observatory, this report having been forwarded by S. Nakano to the Central Bureau on Mar. 27; confusion arose because Tanaka's 4-min exposure was said to indicate a daily motion of more than 4 deg (in p.a. 20 or 200 deg), although it now appears that Tanaka had first detected the comet visually 25 min earlier and that there was no obvious motion. A. Hale's Apr. 1 observation confirms the Machholz discovery, and a parabolic perihelion orbit fitted to the approximate Mar. 31 and Apr. 1 positions satisfies the Mar. 24 Tanaka position within 0.6 deg." 1992 UT R.A. (2000) Decl. m1 Observer Mar. 24.823 21 54.8 +12 55 10 Tanaka 31.505 22 09.5 +18 43 9.4 Machholz Apr. 1.473 22 11.4 +19 33 9.6 Hale Z. Tanaka (Yodoe, Tottori). 0.2-m reflector. Very faint, unmeasurable image on exposure in twilight. Coma diameter 2'. D. Machholz (Colfax, CA). 0.12-m refractor. Object diffuse with some condensation, no tail. Coma diameter 2'. A. Hale (Las Cruces, NM). 0.41-m reflector. Diffuse, somewhat condensed. IAUC 5487 S. Nakano, Sumoto, Japan, communicates the following precise measurements by T. Seki, Geisei. The Mar. 24 measurement is from the photograph taken by Z. Tanaka at Yodoe, Tottori (cf. IAUC 5487). 1992 UT R.A. (2000) Decl. m1 Mar. 24.84234 21 54 50.0 +12 57 34 10 Apr. 1.82409 22 12 18.76 +19 49 07.3 9 IAUC 5488 Guy M Hurst