Mars in 2002–03 – Fifth interim report
At the 2003 October AGM, I gave an illustrated summary of the apparition now ending. The present brief report continues from the December Journal, and covers a further portion of the martian southern summer. It is based upon data received for the period 2003 October 16 (Ls = 280°, D (disk diameter) = 17.7 arcsec, tilt = –21° S) to December 15 (Ls = 316°, D = 9.7 arcsec, tilt = –26° S). Although the planet’s altitude much improved (with the declination only 1° at the end of the period), the number of observations received daily has declined rapidly.
More than a hundred observers (see below) contributed useful work this year. Most recent data continue to show a small south polar cap in its summer remnant phase, a high level of morning terminator clouds, and a north polar hood.
The most interesting thing about the great perihelic opposition of 2003 has been the complete lack of a really major dust storm. In terms of seasonal date, the latest planet-encircling storm ever to begin was that of 1924 December (Ls = 311°). This point has now been reached, and so it seems unlikely (unless existing records are broken) that such an event could now begin during the present martian southern summer.
However, some airborne dust did contrive to produce a dull projecting cloud over Ausonia on the morning terminator on November 8, when the CML lay between 190° and 209°, according to CCD work by Isao Miyazaki (illustrated here). A similar visual record was secured by Mario Frassati (Italy) on November 17 (CML = 201°). Hellas was a little lighter in its northern half, but seems to have remained inactive. Polarisation measures by Richard Schmude (USA) as of November 16 demonstrate a general lack of airborne dust over the longitudes 300–360° (including Hellas).
A final interim report about this apparition will be published later.
Mars, 2003 November 8. CCD images (ToUcam webcam) by I. Miyazaki with 40-cm refl. (Okinawa, Japan). Two pairs of images, with the first normal, and the second brightened in each case to enhance the terminator projection. (Left) 11h 05m, CML = 190°, (right) 12h 21m, CML = 209°.
Richard McKim, Director