This report describes and analyses the observations of the brighter or more interesting comets at perihelion during 2023, concentrating on those for which visual observations were obtained. Magnitude parameters are given for all comets with observations. Any evolution in the magnitude parameters of those periodic comets with multiple returns is discussed. Additional information on the comets discussed here, and on other comets seen or at perihelion during the year, may be found on the Section visual observations web pages.
The earliest known discovery of the 1946 eruption of T Coronae Borealis was made by A. S. Kamenchuk, an amateur astronomer in the Soviet Far East, on 1946 February 8 at about 19:00 UT. In the following few hours, two independent discoveries were made by British amateur astronomers. N. F. H. Knight, a variable star observer from Surrey, detected the nova on 1946 February 9 at 05:40 UT; correspondence between Knight and W. M. Lindley, Director of the British Astronomical Association Variable Star Section, reveals what might be the first prediction of a future eruption in 2026–’27. A slightly earlier independent discovery, however, has been largely overlooked. This was made on 1946 February 9 at ~01:45 UT by a 15-year-old schoolboy, Michael Woodman, observing from Newport, South Wales, when the nova was of magnitude ~2.0. Although credited as an independent discovery at the time, only scant details appeared in contemporary reports. This paper reconstructs the circumstances of Woodman’s observation from his contemporaneous notes and later recollections and evaluates its significance – alongside the observations of Kamenchuk and Knight – for constraining the earliest phase of the 1946 eruption light curve.
OJ287 is a blazar exhibiting high-amplitude variability in all the bands in which it has been studied, from x-ray to radio, over time scales ranging from minutes to decades. It has been particularly well studied in visible light, revealing no clear tendency to show bluer colours when brighter – an interesting anomaly compared to other blazars. It is also one of the active galactic nuclei in which it has proven most difficult to detect the host galaxy: either directly, by resolving it in images, or indirectly, by the change of colour at magnitudes sufficiently faint for the galaxy to be expected to make an important contribution to the total light from the system. Here, we investigate the colour variations of OJ287, finding a slow component of variation with an amplitude of ~0.2 magnitudes on a timescale of years, in both the B – V and V – R colour indices. We identify this tentatively with the effects of the major outbursts that occur every ~12 years. We also find that, contrary to previous findings, OJ287 does show a tendency to bluer colour when brighter, but that these trends are only visible in short segments of data covering a few months to a few years. We interpret this behaviour as due to multiple, overlapping components of emission coexisting, each with its own colour-magnitude correlation. Finally, we show that the colour changes OJ287 exhibits at faint magnitudes are consistent with the host being a giant elliptical galaxy with a magnitude of V = 18.0 and R = 17.1, and that this object can be detected unequivocally, if indirectly, with a backyard telescope.
Noctilucent cloud forms in the mesosphere at an altitude of about 83 km and appears annually in northern latitudes between the end of May and the beginning of August. A number of observers, situated at widely dispersed locations in the UK and Western Europe, report their sightings to the British Astronomical Association. This paper is an analysis of these observations for the summer months of 2024, together with background information about conditions in the mesosphere which contribute to the formation of polar mesospheric ice: the cause of ground-based sightings of noctilucent cloud.
In 1916, the English amateur astronomer and BAA member James Henry Worthington published a beautifully produced book, Sketches in Poetry Prose Paint & Pencil, in a limited edition of 300 copies. The Illustrations, both in colour and monochrome, were created by London-born Robert Peter Baker. This article evaluates a copy of the book to assess how far it reflects Worthington’s enthusiastic support for Percival Lowell’s theory of Martian canals.
Quasar downsizing was investigated using a sample of 832,521 quasars with redshifts between 0.400 and 3.315, from the Million Quasars catalogue. The sample was divided into bins, and in each bin two reference quasars were identified: the ‘99th percentile most powerful’ quasar and the ‘mode’ quasar, as determined from their absolute optical magnitudes. For three binning methods, absolute optical magnitude was plotted against both redshift and distance for these reference quasars, revealing a linear relationship between absolute optical magnitude and redshift (or distance). The 99th percentile most powerful quasar gave a tighter fit than the mode quasar. Of the other parameter choices, redshift yielded better results than distance, and the preferred binning method used approximately 8,000 quasars per bin. The following relationship was derived between the absolute optical magnitude of the 99th percentile most powerful quasar, Mg(99%), and redshift, z: Mg(99%) = (−1.19 ± 0.07) · z − 24.69 ± 0.11.
The total eclipse in 2026 is visible from Greenland, Iceland and Spain; in the British Isles, a large partial eclipse may be seen during the early evening. This paper summarises the circumstances of the eclipse in the British Isles, Iceland and across the Iberian Peninsula.
This study introduces a comet candidate to explain the Star that the Magi associated with the birth of Jesus as described in the biblical book of Matthew. By utilising observations of a comet recorded in Chinese annals in 5 BCE, a novel numerical technique was used to compute an orbit for this comet that could have passed very close to Earth in early June of 5 BCE, exhibiting ‘temporary geosynchronous’ motion. This is the first astronomical candidate for the Star ever identified that could have had apparent motion corresponding to the description in Matthew, where the Star ‘went before’ the Magi on their journey to Bethlehem until it ‘stood over’ where the child Jesus was. The study also examines how the Magi may have been influenced by ancient beliefs about comets, as described in Greco-Roman astrological writings, contemporary cuneiform omen texts, and the belief system of astrological geography. There is also a discussion of how this comet candidate corresponds to the chronology of the events surrounding Jesus’ birth.
We determined rotational properties and the phase curve of the 4-km Vesta-type asteroid (3697) Guyhurst from observations conducted between 2024 February 1 and 2024 June 14. The synodic period was found to be 7.9088 ± 0.0003 h, assuming two photometric maxima and two minima per rotation. Its rotational amplitude at its 2024 apparition was found to be 0.18 ± 0.02 mag. The shape of its phase curve is remarkably similar to that of Vesta, as is its orbit, confirming the object is a fragment of the parent body.
We present a report on observations of Venus made by members of the Mercury & Venus Section of the British Astronomical Association during the 2024–’25 eastern elongation. During this time, a number of interesting phenomena were recorded, including the previously reported cloud discontinuity. It seems that no hot spots on the night side were observed by members. In this report, we analyse the observations and present our conclusions.
Dr William Evan McFarlane FRAS (1866–1919) was a member of the British Astronomical Association and the Royal Astronomical Society. Obituaries published by both organisations in 1919 contained errors about his life. In recent years, he has attracted renewed attention in Queensland, Australia, because of his efforts to popularise astronomy, particularly an object known as the ‘Vulcan Star’, which has become associated with V603 Aquilae. This article presents a corrected account of his life and investigates whether he was the discoverer of the Vulcan Star, and whether the nova’s apparent position and visibility from Irvinebank could explain its association with the Vulcan Mine.
The Sun exhibits differential rotation, with its rotation rate or period varying with heliographic latitude. This short paper demonstrates a method for using full-disc white-light solar images to measure the Sun’s rotation rate at different latitudes. Using images from the Solar Dynamics Observatory, suitable sunspots are selected. The central meridian distance of these sunspots is calculated, and the synodic rotation rates are determined. The paper also explains how to convert synodic to sidereal rotation rates and derive parameters for a differential rotation model. Results are compared with other studies, showing consistency despite the relatively small number of measurements.
The 1961 opposition was unusual in two ways. First, the South Temperate Belt between white ovals FA and BC had faded to near invisibility. Second, the southern part of the Equatorial Zone (EZ) had darkened, so that a dark belt (resembling the normal Equatorial Band, but with a southern edge that was unusually far south) extended from zenographic latitudes +1 to –6°. Spots moving along the centre or northern edge of this ‘Equatorial Zone south Band’ (EZsB) showed near-zero System I drifts, typical of the central and northern EZ, but the prominent humps located upon the south edge of a sector that extended to higher southern latitude were moving in the slower South Equatorial Current. Much of the northern EZ was shaded, and the brighter parts appeared a dusky yellow or orange. There were numerous very broad shadings that united the NEB to the EZsB, and their edges coincided with the usual festoons upon the NEB S. edge. The Great Red Spot had darkened considerably since 1960, especially at its edges, and was intensely coloured. Its centre exhibited a slightly irregular oscillation in longitude, with a period of several months, superimposed upon a slight positive drift. The N. Temperate Belt remained faint. Mutual eclipses and occultations of the Galilean satellites were observed and timed.
A survey of British newspapers has uncovered 41 sightings of sunspots made by untrained people with no optical aid and without prompting. These truly accidental sightings mirror historical (pre-telescopic) western cases where there is no evidence of deliberate, intentional sunspot observation. The survey covered the period since 1874, when the Royal Observatory in Greenwich began compiling daily ledgers of sunspot sizes and positions from photoheliographic observations. This paper explains how candidate press reports were identified and then screened using objective criteria, and presents key results, in particular the circumstances under which the sightings were made, the sizes of the spots concerned, and indicators of solar activity (sunspot count, recurrence, geomagnetic storms) at the time. The survey found that 88 per cent of the accidental sightings were of sunspot groups whose whole spot projected areas exceeded 2,500 millionths of the visible solar disc, much greater than the 1,000 millionths usually quoted as a threshold for visual acuity. Furthermore, a spot ≥4,000 millionths in area was 100 times more likely to be noticed by accident than one with an area of 1,000–<2,000 millionths. Nearly all the accidental sightings were of recurrent groups and the associated mean sunspot number was >200. The possible implications of the results for the interpretation of historical sunspot reports are discussed.
In a classic 1982 paper in this journal, Jean Meeus used a statistical approach for finding the mean frequency of a total and an annular eclipse of the Sun at a given place on the surface of the Earth. In this current paper we tackle the problem again, taking advantage of the much greater computing power now available. We obtain narrower estimates of once every 373 $\pm$ 7 years for a total eclipse, and once every 226 $\pm$ 4 years for an annular eclipse. In addition, we obtain a result of once every 2.59 $\pm$ 0.02 years for a partial eclipse. We provide further insights into the "latitude effect", showing that solar eclipses occur most frequently around the Arctic and Antarctic Circles. We also show how the gradual shift of aphelion and perihelion with respect to the seasons produces a $\sim$21,000-year cycle in the frequency of eclipses in the Northern and Southern Hemispheres.
Observations at long infrared wavelengths by the Akatsuki spacecraft during 2015 December revealed the presence of a remarkable bow-shaped high-albedo atmospheric wave, elongated north–south and stretching over both hemispheres across a wide range of latitudes, up to 10,000km in length. Its velocity was nearly zero with respect to the surface, and its initial longitude placed it at the western side of one of the three highest regions of the planet. Amateur data at shorter infrared wavelengths recovered long, narrow N–S elongated waves or discontinuities in late 2016 and again during 2019–’20, but they showed typical velocities for that waveband, corresponding to synodic rotation periods of around five days. This short note reviews the Akatsuki data and more recent ground-based observations. Furthermore, it speculates whether waves could also have been generated by the possible surface volcanic activity first reported in BAA observations during 2017.
AbstractIm Jahre 1969 brachte Apollo 11 die ersten Menschen auf den Mond. Anlässlich des 50‐jährigen Jubiläums wurde eine Roadshow konzipiert, die durch mehrere Städte der Vereinigten Staaten von Amerika reisen sollte. Hierfür wurde ein großes mobiles Theaterzelt mit 1 600 Sitzplätzen entwickelt. Als fliegender Bau besteht dieses Zelt aus Einzelelementen, die auf schnellen Aufbau und leichten Transport optimiert sind. Eine bogengestützte Hauptmembrane, eine elastisch gelagerte Projektionskuppel und eine große ETFE‐Fassade bilden die verschiedenen Hüllen und nehmen dem Projekt den Zeltcharakter. Anpassbare Fußelemente, verankert mit langen Erdnägeln, dienen als flexible Gründung für die verschiedenen Aufstellorte. Im Sommer 2019 stand das temporäre Theater für „Apollo 11 – the immersive live show“ in Pasadena, Kalifornien.
