{"id":3160,"date":"2025-02-19T11:37:54","date_gmt":"2025-02-19T11:37:54","guid":{"rendered":"https:\/\/www.popastro.com\/planetary\/?p=3160"},"modified":"2025-02-19T11:37:54","modified_gmt":"2025-02-19T11:37:54","slug":"planetary-section-report-december-2024-and-january-2025","status":"publish","type":"post","link":"https:\/\/www.popastro.com\/planetary\/2025\/02\/19\/planetary-section-report-december-2024-and-january-2025\/","title":{"rendered":"Planetary Section Report; December 2024 and January 2025."},"content":{"rendered":"

This has been the best reporting period for some considerable time, with all the major planets bar Mercury observed by the section.<\/p>\n

I will start with Venus, a steadily improving evening object very obvious in the south-eastern sky after sunset. Dave Finnigan caught an ultraviolet view on 30 December with the planet showing only a little more than 50% phase and some large-scale darke patches visible, typical of UV images; the mysterious \u2018great absorber\u2019 of solar UV light at play in the Venusian atmosphere.<\/p>\n

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John Chapman Smith made an eyepiece-projection image with a DSLR on 02 January which suggests 50% visible phase. Accurate dating of \u2018dichotomy\u2019, the exact point of half-phase, is easy by calculation but much harder by observation. The thick atmosphere of Venus combined with the dispersion of incident light from the Sun makes it hard to pin down the date; this is the well known \u201cSchr\u00f6ter Effect\u201d. Visual assessment is harder than photographic, but the effect is real.<\/p>\n

R M Steele made a series of observations from 02 to 15 Jan\u2019 and assessed dichotomy to occur on the 6th<\/sup>, some five days before the official calculation based on orbital dynamics. This is in line with established observation with dichotomy appearing early during evening apparitions. Dave Finnigan made images in the UV, visual and infrared wavelengths on 12 Jan that strongly suggest less than 50% visible phase. This was confirmed by Paul Crossland on 16 Jan\u2019 and by further images from Dave taken on the 24th<\/sup>.<\/p>\n

Next Saturn, which was moving towards the end of its current apparition, with the planet being a low evening object. It was observed by David Graham on 26 Dec\u2019 and Dave Finnigan on 02 Jan\u2019. David Graham\u2019s sketch notes how dull the ring system appears with the Equatorial Zone (EZ) as the brightest feature. This compares very well with Dave Finnigan\u2019s image. The ring system is currently closing and, when we next get to observe it, we will see the south side of the rings rather than the north.<\/p>\n

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Dave Finnigan also contributed images from Uranus and Neptune in both white-light and the near IR. The latter gives the best chance of catching storm activity on these \u2018Ice Giants\u2019 however nothing was revealed in these images.<\/p>\n

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Mars was at opposition on 16 January meaning Earth sat almost directly between the Sun and Mars. The northern hemisphere (NH) of Mars is moving into spring and dark banding should be noted around the north pole as frozen gas sublimates into the thin atmosphere. Dave Finnigan\u2019s image from 16 Dec\u2019 has the brighter patch of Elysium Planitia near the Central meridian (CM) and shows the dark sub-polar regions well. The darkening is also noted on David Graham\u2019s sketch from 19 December and in images from Steve Norrie and myself from the 28th<\/sup>. These latter two show Xanthe Terra but caught no extensive cloud formation, which might be expected of this period.<\/p>\n

David Graham made a string of sketches from 01 to 10 Jan\u2019 that may be compared with images by Paul Crossland from 02 Jan\u2019and Martin Lewis from the 10 and 11th<\/sup>. Martin\u2019s images are exceptionally detailed. Made from multiple videos de-rotated to a common time in Winjupos software, they do show some cloud at the edges of both polar regions and a \u2018softness\u2019 to the south of Terra Meridiani that may be a localized dust event; the crater Schiaparelli is just visible on the CM.<\/p>\n

Steve Norrie\u2019s images from 10 Jan clearly shows major albedo features while, around this time, Chris Campbell took some pictures with his outstanding 8\u201d aperture apochromatic refractor; you read that right, 8\u201d aperture! Taken with a One Shot Colour (OSC) camera, these are good images but I would welcome details of date and time, if you read this Chris! Dave Finnigan\u2019s Images from 12 Jan show Arabia Terra well, then more images followed from Martin in \u201cvery good seeing\u201d on the 15th<\/sup> and Paul Crossland from the next night. Martin\u2019s image showcases Syrtis Major and Hellas but, again, major cloud activity is scarce. Final images came from Martin on 22 and 30 Jan\u2019 and Dave Finnigan on the 25th<\/sup>. Mars is somewhat small during this opposition but its altitude from the UK helped provide decent seeing conditions, improving results.<\/p>\n

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Remaining space now compels me to move on to Jupiter. Rather then list a detailed chronology I will thank the contributors and then summarize the main findings. Therefore, many thanks to Dave Motterhead, Steve Norrie, John Chapman Smith, Paul Crossland, Chris Campbell, David Graham, Martin Lewis and Dave Finnigan.<\/p>\n

Jupiter has been very active throughout the period. In fact major activity started on 11 November, in the last reporting period, when a brilliant white dot was noted in the South Equatorial Belt (SEB). This developed into a major outbreak cutting diagonally across the belt, stretching from the South Tropical Zone and through to the EZ. This outbreak managed to hide itself from the section throughout December, so was well developed by the time it was finally caught in early January.<\/p>\n

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Dave Mottershead\u2019s image from 20.58UT on 19 Dec\u2019 may have had the rift appearing on the extreme limb but it is not clearly discernable. Sadly images from Steve Norrie and myself from 28 Dec\u2019 missed it, as did those from Paul Crossland and Martin Lewis from 01\/02 Jan\u2019 and others from around these nights: Martin\u2019s images did catch detail on Ganymede and showed how pale Oval BA has become as did Dave Finnigan\u2019s pictures from the same night.<\/p>\n

A series of images from David Graham in early January also missed the SEB outbreak, and this is understandable as, initially at least, it had a small and inconvenient observing window. Then David, Steve Norrie and Martin Lewis caught the outbreak on 10 Jan\u2019, when it was revealed as a \u2018coiled rope\u2019 of twisted gases laying along the SEB from L3\/100 degrees (where the outbreak had started) to L3\/48 degrees. In addition, in Martin\u2019s image taken at 20.17UT that night, a tiny but bright dot appeared at approximately L3\/25 degrees, sitting just north of the NEB. This was the first appearance of a North Temperate Belt, southern edge (NTBs) outbreak that was discovered only slightly earlier that night by amateur Clyde Foster, observing from Namibia. Martin was extremely close to making the \u2018discovery\u2019 image. Chris Campbell\u2019s images from around that time clearly show the SEB disturbance but not this newer event.<\/p>\n

My own image from 14 Jan shows the bright NTBs spot with just a hint of dark turbulence behind, following its very rapid motion along the planets most powerful jet-stream. Dave Mottershead\u2019s image from the next night shows the SEB disturbance across the CM while, by 21 Jan\u2019, the NTBs disturbance had stretched to over 30 degrees in longitude, still spearheaded by an obvious white bright \u2018spot\u2019 of very high cloud. Dave Finnigans image from 25 Dec\u2019 shows a further stretch in length, as does mine from the 28th<\/sup>; now to over 90 degrees in longitude. Finally Martin Lewis showed on 30 Jan\u2019 a length close to 120 degrees, with a new white outbreak leading the original spot.<\/p>\n

The section is congratulated on its excellent work in this period.<\/p>\n

Alan Clitherow.<\/p>\n","protected":false},"excerpt":{"rendered":"

This has been the best reporting period for some considerable time, with all the major planets bar Mercury observed by the section. I will start with Venus, a steadily improving evening object very obvious in the south-eastern sky after sunset.Read more<\/span><\/a><\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[3],"tags":[],"class_list":["post-3160","post","type-post","status-publish","format-standard","hentry","category-reports"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t