The SPC continues to shrink, and is too tiny upon the sub-6 arcsecond diameter disk to offer any interior details. There is little sign of any white cloud, though some weak cloud has sometimes been visible along the north limb, indicating a nascent N. polar hood. The evening orographic clouds have not yet been sighted, and I remind observers that to detect them easily one needs a deep blue or violet filter, at least when the disk diameter is as tiny as it still is. Little dust activity has been evident of late, but on June 23 Foster imaged a small (and hardly detectable) dust storm to the south of Propontis (in the light region labelled Azania upon the Ebisawa standard map), which was also seen by the MRO spacecraft. His images of June 22 and 25 do not obviously show it. His June 23 image is posted here, together with drawings by Makoto Adachi and an image by Niall MacNeill.

Several more observers have joined in our programme, and I have now produced a Word document listing all of them, which is posted upon the front page of the Mars Section. It will be updated as necessary.

Front page teaser image:

A shrinking S. polar cap, and a very small dust storm near Propontis. By Clyde Foster

Previous Post – 31 May 2024

More observers have now joined in. Highlights since the last post are: (1) During April 21-25 Clyde Foster caught a light patch of dust lying along the E. part of Valles Marineris, east of Aurorae Sinus, which was then accessible to him fairly close to the evening terminator. Spacecraft data show that this was a regional dust event that had spread somewhat further. Regions to the immediate E. looked nearly normal as they became visible from his longitude, but were lacking somewhat in contrast. During April 23-25 what appears to have been a dust streak elongated in the E-W direction can be made out near the N. edge of the SPC. (If Pandorae Fretum subsequently darkens, it will show that dust excavation had occurred as far as those longitudes.) (2) Some other local dust activity has been spotted along the N. edge of the S. polar cap. For example Foster’s image of May 27 shows a streaky bright area which can be seen in IR, R and G, but not in B. (3) The seasonal separation of Novus Mons from the spring SPC was complete at Ls = 238^o in 2020. At that seasonal date in 2024 the disk diameter was below 5”, but nevertheless Foster’s images of Apr 29-May 6 (Ls = 245-250^o) show the cap elongated in the correct longitude, with a hint of separation on the best images on some days. A trace of the much decayed outlier was caught by Mark Lonsdale on May 22 (Ls = 260^o), but only the best images will have a chance of resolving it.

Now is the best time to watch for more significant dust storm activity and I encourage those of you able to rise early to monitor the planet whenever you can in order to maintain continuity of coverage.

Previous Post – 7 April 2024

Next Post – 5 July 2024

The 2024-25 apparition of Mars has begun. In fact, ever since 2024 January 10 we have been receiving a series of excellent images from Clyde Foster (Namibia). These are remarkably good given that the planet’s disk diameter has so far hardly exceeded 4 arcseconds. Several of the results are posted here, with south up as usual, including images until the last few days. These show the gradual shrinkage of the S. polar cap, and the usual seasonal development of dark patches and rifts within it. The Hellas basin now appears lighter in the centre than it did in February, but no specific dust storm event has yet been recorded. The Mare Serpentis area is broad and dark, which is suggestive of a recent past event in Hellas. On March 14 Clyde even resolved some of the Tharsis Montes as tiny dark patches. The Indus streak (which in the past would have been called a canal), which runs between Oxia Palus (at the N. tip of Margaritifer Sinus) and the SE corner of Mare Acialium/Niliacus Lacus, has already been imaged. This is an area of particular interest, darkening during the 2018 planet-encircling dust storm, and persisting throughout the next two oppositions.

I am hoping that other early morning observers will soon join in the programme, and in particular I am keen that observers at other terrestrial longitudes will do so, enabling us to watch all sides of the planet simultaneously. By not doing so we risk missing short-lived local dust storms.

For a detailed Mars map, and lots of martian names, see the 2022 chart by Martin Lewis posted on the front page.

Opposition is still a long way off, and will not occur until 2025 January 16. A detailed note about which seasonal phenomena can be observed (and when) will be appearing in the June issue of the BAA Journal. I am including here only a copy of the ‘seasonal protractor’ showing the current 15/17-year cycle of oppositions, to include 2025.

An early pre-opposition preview was given by the Director at the 2024 March BAA Meeting; if you are interested, the presentation is still available on our YouTube channel simply by following the link below from around 2 minutes onwards:

https://m.youtube.com/watch?v=jHMM4efBYw4

This blog will be updated at irregular intervals. Keep watching for the latest news.

Next Post –  31 May 2024