A new calibrated sunspot group series since 1749: statistics of active day fractions

Although the sunspot-number series have existed since the mid-19th century, they are still the subject of intense debate, with the largest uncertainty being related to the "calibration" of the visual acuity of individual observers in the past. Daisy-chain regression methods are applied to inter-calibrate the observers which may lead to significant bias and error accumulation. Here we present a novel method to calibrate the visual acuity of the key observers to the reference data set of Royal Greenwich Observatory sunspot groups for the period 1900-1976, using the statistics of the active-day fraction. For each observer we independently evaluate their observational thresholds [S_S] defined such that the observer is assumed to miss all of the groups with an area smaller than S_S and report all the groups larger than S_S. Next, using a Monte-Carlo method we construct, from the reference data set, a correction matrix for each observer. The correction matrices are significantly non-linear and cannot be approximated by a linear regression or proportionality. We emphasize that corrections based on a linear proportionality between annually averaged data lead to serious biases and distortions of the data. The correction matrices are applied to the original sunspot group records for each day, and finally the composite corrected series is produced for the period since 1748. The corrected series displays secular minima around 1800 (Dalton minimum) and 1900 (Gleissberg minimum), as well as the Modern grand maximum of activity in the second half of the 20th century. The uniqueness of the grand maximum is confirmed for the last 250 years. It is shown that the adoption of a linear relationship between the data of Wolf and Wolfer results in grossly inflated group numbers in the 18th and 19th centuries in some reconstructions.

Opening movements in Ophuls: Caught (and Madame de …)

This audiovisual essay was created at the wonderful NEH-funded workshop in videographic criticism at Middlebury College, ‘Scholarship in Sound and Image’. The essay provides an analysis of the orchestration of long takes and camera movement in the opening of Caught (Ophuls, 1949), and develops a comparison with the opening of Madame de… (Ophuls, 1953 – U.S. release title The Earrings of Madame de…), not least through a series of juxtapositions, which can be directly presented and compared in an audiovisual essay. The openings share a concern with the subjectivity of the female protagonists and our relationship toward it, evoking the women’s experience while balancing this with other kinds of perspective. As has been noted in the critical literature on Ophuls, and on melodramas of passion more generally, such views enable us to perceive the women concerned to be caught in material and ideological frameworks of which they are at best partially aware. Among the interests of this particular comparison, however, is the extent to which the dynamic around female subjectivity is played in relation to luxury goods, imagined, owned or admired. Tensions between on- and off-screen spaces and sounds are critical to the interest of the long takes under discussion. Camera movements subtly inflect the extent to which we are aligned (or otherwise) with the characters and the ways in which their material circumstances are revealed to us.