[en] J. Crovisier, P. Colom, N. Biver, D. Bockelee-Morvan, LESIA, Observatoire de Paris; and I. Cognard, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, Universite d'Orleans, report: "While monitoring the 18-cm lines of OH in comet 88P/Howell at the Nancay radio telescope, we serendipitously observed the occultation of the radio source PKS 1416-15 by the comet on Aug. 15.69 UT. This point radio source, which has a flux of about 2 Jy at 18 cm, was then 2'.2 from the comet nucleus, corresponding to a projected distance of 125000 km. The 1667-MHz line area was then observed to be -250 +/- 25 mJy*km/s, enhanced by a factor of 5 with respect to the signal as averaged for +/- 6 days before/after the event. This can be explained by the OH maser amplification of the background radio source radiation. The OH production rate averaged before/after the occultation was estimated to be 3.3 x 10**28 molecules/s. A similar event was observed on 1989 Oct. 13 for comet C/1989 Q1 (Crovisier et al. 1989, IAUC 4882; Crovisier et al. 1992, A.Ap. 253, 286)." <P />E. Jehin, STAR Institute, University of Liege, reports (together with Y. Moulane, J. Manfroid, F. Pozuelos, and D. Hutsemekers) that they obtained narrowband photometry of comet 88P with the robotic 0.6-m "Transiting Planets and Planetesimals Small Telescope" (TRAPPIST-North) at Oukaimden, Morocco, on Aug. 17 (with the comet at r = 1.42 AU and Delta = 1.31 AU), using the HB comet filters (cf. Farnham et al. 2000, Icarus 147, 180) that focus on seven cometary emissions and four continuum bands. Using a Haser model (with V_p = V_d = 1 km/s, for 10000 km and correcting for the phase angle) they computed the dust-production rate proxy (as explained on CBET 4691) by profile fitting and correcting for the phase angle: A(0)f[rho](R) = 372 +/- 9 cm. They determined the following molecular production rates: Q(OH) = 2.97 (+/- 0.17) x 10**28 molecules/s, Q(CN) = 4.86 (+/- 0.10) x 10**25 molecules/s, Q(C_2) = 5.59 (+/- 0.12) x 10**25 molecules/s. <P />Selected recent visual total-magnitude and coma-diameter estimates: Apr. 15.46 UT, 14.4, 0'.8 (C. Wyatt, Walcha, NSW, Australia, 0.40-m reflector); 18.48, 13.9, 1' (P. Camilleri, Katherine, NT, Australia, 0.40-m reflector); May 10.39, 13.6, 0'.8 (Wyatt, 25-cm reflector); 21.87, 13.0, 0'.3 (W. Hasubick, Buchloe, Germany, 44-cm reflector); June 9.48, 12.2, 3' (Camilleri); 16.37, 11.7, 3' (Wyatt, 25-cm reflector); 20.94, 10.7, 4' (J. J. Gonzalez, Leon, Spain, 0.20-m reflector); July 12.98, 11.2, 2' (M. Goiato, Aracatuba, Brazil, 0.22-m reflector); 18.43, 10.6, 3' (Camilleri); 24.91, 10.1, 3'.5 (Gonzalez); 30.37, 10.3, 4' (Wyatt, 25-cm reflector; moonlight); Aug. 8.98, 10.3, 3' (Goiato); 13.88, 9.4, 7' (Gonzalez); 19.48, 9.3, 4' (K. Yoshimoto, Yamaguchi, Japan, 20x100 binoculars); 23.92, 9.6, -- (J. G. de S. Aguiar, Campinas, Brazil, 25x100 binoculars; moonlight); 27.92, 9.4, -- (Aguiar, 0.27-m reflector).
