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Cheers Jeremy – it was my fault as I just noticed I had added a blank space at the end! I think it works from my original post now as well…
Thanks for the link Jeremy. Yet another recent one (with somewhat more enlightening conclusions regarding RSG mass-loss mechanisms) is from Roberta Humphreys and Terry Jones at UMinn. It can be found at: https://arxiv.org/abs/2201.07818
This includes discussion of Betelgeuse and comparisons with the hypergiant VY CMa.
Great pictures Bill. The one of AR2546 coming around the limb in particular looks wonderfully three-dimensional. Your brightness plot is interesting and, with the help of Messrs Stefan and Boltzmann (and the back of a convenient envelope!), suggests a temperature at the visible depth limit on the limb of just under 4540K, which is about what you would expect, given the usually quoted figure of 4400K for the top of the photosphere (as you suggest, the number is distorted a bit by the blue filter but the plot does suggest a temperature neatly in between that to be expected in the umbra and penumbra of the sunspot – it might be interesting to check against pixel values there too). Plotting across a range of wavelengths should indeed provide a more accurate result.
Cheers
Tim
Quite a bit of low cloud and strong winds in Haslemere (South West Surrey), but there were decent breaks in the cloud during the first couple of hours of the transit to reward patient observation.
I was interested in Stewart’s comment that nothing was visible in 10×50 bins with the poor seeing at Thorpe-le-Soken. I used Lunt 11×70 bins with Orion solar filters and in the intermittent moments of good seeing, Mercury was very distinctly visible as was the sunspot group AR2542. Both were easy to pick out. The smaller sunspots near to 2542 and those near the solar equator were only very briefly visible in a single very steady moment of seeing (and, yes, I saw those before checking photos of the solar disk!). With only the binoculars and lots of cloud, first and second contact were not observed, I could only pick up Mercury once fully on the solar disk at 1116UT.
I had the Lunts mounted on the rather nifty Orion Paragon parallelogram mount which made for a comfortable and steady set up notwithstanding the tendency for it to act like a weather vane in the prevailing winds!
Thanks from me as well to all those who have posted some great pictures.
Cheers,
Tim
