Archives

By observing the polar regions of the Sun on three occasions and in three wavebands, polar faculae in the photosphere were studied and compared to features found in the chromosphere at wavelengths of calcium II K and hydrogen-alpha. It was found that the white-light polar faculae are closely associated with calcium II K bright plage, but more tenuously associated with hydrogen-alpha plage. Associations were more consistent for hydrogen-alpha mottles, although non-specific correlations could not be excluded.

Remarkably, the five largest recorded sunspot groups all occurred during a period of just over five years, from 1946 February to 1951 May, during Solar Cycle 18. These are the only groups known with areas greater than 4,500 millionths of the Sun’s visible hemisphere. This paper examines the white-light activity of the groups.

The recent so-called ‘Great Conjunction’ of Jupiter and Saturn, in 2020 December, was the latest in a series of conjunctions of the two planets that occur, on average, every 19.67 years. Although events between Jupiter and Saturn are visually not the most spectacular of conjunctions, they are of great historical interest due to the triple conjunction that occurred around the time of the Nativity, which authors such as Hughes (1976) have associated with the Star of Bethlehem. A total of 309 Jupiter–Saturn conjunctions are found between 1000 BC and AD 4000, which include 84 grouped in 28 triple conjunctions. The 2020 conjunction is found to be in the top five percent of closest approaches of the two planets over five millennia. The closest conjunctions show a strong preference for occurring in Cancer in July/August, or Capricornus in December.

Observations of 43 complete transits of the hot Jupiter exoplanet HAT-P-32b using the MicroObservatory 0.15m robotic telescope network, covering a period of seven years, are presented. Compared with the most recent ephemeris for the system, the precision of the mid-transit times yields a root-mean-square value from the predicted model of 3.0min. The estimated system parameters based on EXOFAST modelling are broadly consistent with the default parameter values listed in the NASA Exoplanet Archive. An updated orbital period of 2.15000815 ± 0.00000013d and ephemeris of 2458881.71392 ± 0.00027BJDTDB are consistent with recent studies of the system using larger telescopes. Using this updated ephemeris, the predicted mid-transit time for a notional observation of HAT-P-32b by the NASA JWST mission in mid-2021 is improved by 1.4min compared with the discovery ephemeris and is approximately eight times more precise. Likewise, the mid-transit time for an observation by the ESA ARIEL mission in 2020 is improved by 1.7m

Since the invention of the telescope, observers of Venus have often reported irregularities in the shape of the planet’s terminator and cusps. Some of these, such as terminator undulations, might be easily ascribed to poor seeing conditions; others, such as cusp extensions near inferior conjunction, are undoubtedly real and evidence of Venus’s atmosphere. This paper considers a third category: detached points of light recorded by several observers at the cusps of the planet, explained by some as high mountain peaks catching the sunlight. Among those who argued for the existence of such mountains was Johann Schröter, a stance that brought him into conflict with the views of William Herschel. Nowadays the ‘ghost mountains of Venus’ are seen for what they are: an illusion encouraged by a growing belief in the plurality of Earth-like worlds.

In Part I we described the interplay of airborne and settled dust with surface features. Here we review meteorological phenomena. Seasonal date limits for the Equatorial Cloud Band and orographic clouds were similar to past years. Despite an unfavourable value of tilt, north polar spiral clouds were witnessed during Ls = 126–153°. Frontal systems, in the form of bands of clouds inclined to the equator and moving off the N. polar region, were recorded. Observers watched to see if the near-opposition coincidence of the sub-Earth and subsolar latitudes on 2016 May 20–21 would result in ‘flashes’ from the Schiaparelli crater in Edom, as in 2001, but the +10° coincidence in the latitude fell too far north, and none were reported. The detachment of Olympia from the NPC occurred by Ls = 72°. The N. polar cap was progressively covered by the hood during Ls = 163–172°, later than in 2014, while the cap summer remnant was larger in 2016; the recession was less extensive than in 2014. Novus Mons separated from the shrin

Observations of Neptune, obtained both visually and by imaging in 2014 and 2015, are presented. In both years, long-lived bright atmospheric features on the planet were detected. For 2015, the daily drift of a major bright storm over a period of four months was determined.

This report describes observations of Uranus made during the 2015 apparition and subsequently submitted to the Section. Throughout this apparition, specific bright zones and dark belts were recorded both visually and digitally, and some variations of detail within them were identified.

‘Reggie’ Waterfield was the BAA’s 33rd president and its most prolific comet photographer from the 1930s to the 1980s. He was also an eclipse chaser and a leading haematologist. Part II covers the World War II era, Reggie’s fight back from a devastating illness, his BAA presidency, and the establishment of a dedicated team of comet photography assistants. The numbering of figures and references continues consecutively from those in Part I [131(3), 158–170 (2021)].

The opposition of 2016 May 22, during Martian Year 33, was the last in a series of aphelic approaches. There had been no obvious albedo changes since the previous opposition. The light yellow area of dust fallout on the NW side of Elysium showed an obvious opposition brightening, and there was also a brightening of the outer rim of Olympus Mons. Three of the various dust storms commenced in unusual or unique locations: in particular, a Regional one in SW Arcadia, and two around Mare Sirenum. A darkening and broadening of Mare Serpentis and a reappearance of Pandorae Fretum resulted from a Regional storm in September. There was no planet-encircling event, but just beyond the recognised seasonal limit for this phenomenon, two Regional events began in the north and expanded in the south; these occurred unusually close together in time. Part II will discuss meteorological aspects and the behaviour of the polar regions.