Mars Section Report No. 8

1997 March 16–31

General

D: 14.1 to 13.9 arcsec (14.2 arcsec at opposition on Mar 17; closest approach Mar 20), Ls: 91 to 98 deg. New contributors were Arthur Bowyer, Andrew Farr, Alan Heath, Michael Hendrie, Lee Macdonald, Dr Patrick Moore, Dr Stewart Moore, David Strange and Peter Wade in the UK, Emilio Colombo in Italy and Gerard Teichert in Frnce. Thanks also to Wolfgang Meyer for German Mars observations. UK weather and seeing conditions were often good. Check out the incredible new HST images on the web, at http://oposite.stsci.edu/pubinfo/PR/97/09.html.

North Polar Region

No N. polar haze was evident in white light. Schmude on Mar 27 found a small detached part of the cap near long. 340 deg (probably the same feature observed by Devadas on Mar 7). Olympia was well shown in the CCD work by Dijon and Strange, and visually by Fisher and McKim. Hyperboreus Lacus was widely observed, and from it extended a thin dark fringe to the NPC covering a wide range in longitude. Warell reported a difficult, N–S rift in the cap on Mar 23 (CML 244 deg., 16-cm OG) and 24 (CML 246 deg., 36-cm OG).

Surface features

Much fine detail has been drawn and imaged, despite the small size of the disk at opposition. In excellent seeing Cave could see Juventae Fons. The southern regions were still foreshortened but Solis Lacus clearly remains large and dark; no internal details have been detected. No-one has reported Phasis this apparition, but it is a delicate feature even when the presentation is favourable. Likewise Gallinaria Silva, the ‘oasis’ at the N. end of the latter; this has probably faded. The Melas Lacus–Tithonius Lacus complex is rather dark. The OAA drew attention to the lack of redness in Thaumasia compared with Daedalia–Memnonia–Amazonis. CCD work by Strnage and visual work by Warell suggests that the Nodus Alcyonius is faintly joined to S. Utopia by a half-tone shading; this area also darkened between 1982 and 1984, before fading again.

Dust storms (yellow clouds)

There is nothing positive to report.

White clouds

(A few interesting points, not a complete account; w.c. activity remained high.) Small white clouds were seen on the borders of Nilokeras by Cave on Mar 19 (between Niliacus L. and Achillis F.) and 21 (W. Tempe). Tempe was generally not very bright near mid-disk but was light in the morning and evening. Hellas remained very bright, especially in its NW (Nf.) corner. A large cloud habitually covered Libya–Isidis R. on the morning terminator. A wide general ‘Blue Clearing’ is apparent from several observers’ work.

Personal

The writer is very sorry to have to report the death of Dr Leonard Martin in early April. Leonard made some outstanding analyses of the great dust storms of the 1970s in a long professional career at the Lowell Observatory. He had retired only recently. The Director met him at Flagstaff in 1994, and was given every assistance with regard to the observatory’s archives. On several occasions Leonard gave valuable advice to both the BAA and ALPO.

Richard McKim, Director

1997 April 19