Mars in 2005–06 – Second interim report
This report was published in the BAA Journal for 2006 June
This second and final interim report briefly reviews other aspects of the recent opposition not covered by the first report (J. Brit. Astron. Assoc., 116, 6 (2006)), which was devoted to dust activity. As at the time of writing – late in the wintry spring of 2006 – the planet can still be viewed in the evening sky, but its disk diameter has recently dropped below 6 arcseconds.
It is interesting to compare the amount of material contributed at the similar opposition of 1988, which received a similar level of participation. (1988: 118 contributors; 2005: 111 contributors (so far).) In 1988 the Director filled seven box-files with BAA drawings and photographs. This year the paper results occupy just one box-file, and the CCD work fills one CD-ROM. The number of CCD and webcam images is for now too high even to count! Examples by Mobberley and Peach as well as some from new contributors P.J. Garbett and M.M. Taylor feature in Figure 1. Although the number of visual observers has declined, the Director (between 2005 early June and 2006 late March) was able to make nearly 140 drawings (of which an example appears in Figure 2), and significant numbers of visual observations were also sent by the following: G. Adamoli, N. Biver, N.M. Bone, A.W. Heath, C. Hernandez, K.C. Howlett, N. Longshaw, P.W. Parish, Mrs E. Siegel and G. Teichert. Encouragingly, the list includes some new contributors. J.R. Fletcher and W.P. Sheehan were able to observe from the Lick Observatory, and I. Hancock had some views from Flagstaff.
Just prior to opposition we were sorry to hear of the death of Harold Hill at the age of 85. Harold – a noted visual observer of the Moon and planets – had been observing up to a few days before his death, and we are grateful to Edward Hill (his son) for the loan of an original notebook for the purpose of reproducing some of Harold’s work here as a tribute (Figure 3). Harold had occasionally contributed to the work of the Section since the 1945/46 opposition.
In the figure captions the Director has added some comments and quotations. In the latter, less dusty stages of the apparition, observers were able to document the formation of the S. polar hood above the residual cap, to record the changing meteorology and to pinpoint the transition from N. polar hood to ground cap (the latter around 2005 mid-February, Ls ~10º). The early behaviour of the spring NPC was also followed.
I hope observers will monitor the planet for as long as they can: solar conjunction will not be until 2006 October 23. For those who have already quit, Mars will again be at opposition on Christmas Eve 2007.
Figure 1 : UK CCD work
Disk diameters are not to scale
A CCD image by Martin Morgan Taylor, 203-mm catadioptric, f/25, Philips ToUcam webcam, LRGB composite, 2005 November 21d 00h 48m, CML = 29º. Bluish a.m. clouds and bluish NPH (partially covering Mare Acidalium). Fine details in S. Chryse and around Valles Marineris.
B CCD image by Martin Mobberley, 254-mm refl., f/50, Lumenera USB 2.0 LU075M webcam, RGB composite, 2005 September 21d 02h 56m, CML = 256º. Nodus Alcyonius, unchanged during the last two decades (with Nepenthes again invisible), is at the CM. Hellas shows floor details. Throughout 2005 the N. part of Ausonia (Trinacria on the IAU map) has been lighter than it was in early 2003 due to dust deposition from the major dust storm activity of the last opposition.
C CCD image by Peter Garbett, 300-mm Schmidt–Cassegrain, f/41, ATK-1HS II CCD camera, RGB composite, 2005 October 23d 03h 23m, CML = 332º. Hints of dust at the SW (Sf.) limb. Many fine details on the N. edge of Sinus Sabaeus and across Noachis. Also note a dark patch within the Huygens crater SW of Syrtis Major, in Iapigia.
D CCD image by Damian Peach, 235-mm Schmidt–Cassegrain, f/42, Lumenera USB 2.0 LU075M webcam, RGB composite, 2006 March 22d 18h 29m, CML = 239º. Many fine details despite the 6 arcsecond diameter image. The NPC is visible, with a dark band to its south. Elysium is dull and cloud-free; following it, the Aetheria development (1978–) remains.
Figure 2 : UK visual observations – I
Drawing by Richard McKim, with 410-mm Dall–Kirkham Cassegrain, x410, x512, white light + W23 orange filter, 2005 November 6d 21h 20m, CML = 112º. Solis Lacus appears large and complex (as in 1986–2003); Phasis is well seen following it (as in 2003). The circular bright spot in the N. hemisphere marks the place of Olympus Mons. A faint orographic cloud is also shown near Arsia Mons. Dark areas and deserts were mottled all over. Caralis Fons (Newton crater) was visible as a dark spot S. of Mare Sirenum. Mare Sirenum appeared dark blue and showed much structure; its W. end seemed to be returning to the classical configuration it showed before the 1986 opposition.
Figure 3 : UK visual observations – II
Pre-opposition drawings by Harold Hill with 203-mm Maksutov–Cass. x333. The disk diameters are drawn to the same relative scale.
A 2005 July 11d 02h 50m, CML = 221º, D = 9.9 arcsec. ‘SPC – 35º diameter?… Maria – sage green.’
B 2005 September 12d 02h 30m, CML = 335º, D = 15.4 arcsec. ‘Syrtis Major and Sinus Sabaeus dark grey or greenish grey… Central regions a pale salmon… Mare Serpentis dark to the west of a creamy Hellas.’
C 2005 October 14d 01h 10m, CML = 19º, D =19.3 arcsec. Most maria were described as greenish, but the coloured original sketch shows Margaritifer Sinus bluish. Noted also were the tiny S. polar cap, bright N. polar hood with its bluish, irregular S. edge, and the bright cloud from Eos to Chryse: an early sign of the large regional dust storm that had begun earlier that night.
Richard McKim, Director