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Stephen Johnston @stephenaj.bsky.social · 15h

As little as possible - I strongly suspect they're not for EIDA analysis! Surely they're just there to signal geometry and astronomy in an impressionistic rather than realistic way - no? (Especially the lower one, where the triangle doesn't even reach the implausible crescent of the moon....)

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Stephen Johnston @stephenaj.bsky.social · 15h

That's funny - I was also struck by the incongruously modern engraved lettering of Venus the last time I was in Dresden, and so took almost exactly the same image. The contrast between the sumptuous original decoration and this later identification of the planet is pretty extreme....

Detail of circular scales and colourful enamelled decoration on the planetary clock of Elector August, Dresden MPS, with later engraved identification of Venus.

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Stephen Johnston @stephenaj.bsky.social · 16h

As a museological exercise, it would be interesting to compare with the GNM exhibition from more than 20 years ago: "Quasi Centrum Europae: Europa Kauft in Nürnberg 1400-1800" (though I didn't see that either). How thoroughgoing is the shift in perspective from Europe to the global world in 2025?

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Reposted by Stephen Johnston

Stephen Johnston @stephenaj.bsky.social · 1d

Decided that jaunty isn't quite the right word in such cases. More like determinedly oblique? (Prompted by stumbling on this example of an astrologer from 1675, in a series of prints under the wonderful title Le Ventiquattr'Hore dell'humana felicità www.ashmolean.org/collections-...)

Detail from a 1675 etching with the figure of an astrologer holding a book and reaching towards an armillary sphere with a pair of dividers. The pedestal on which the sphere sits has a sheet of diagrams and a horoscope on an unrolled scroll.

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Stephen Johnston @stephenaj.bsky.social · 1d

Decided that jaunty isn't quite the right word in such cases. More like determinedly oblique? (Prompted by stumbling on this example of an astrologer from 1675, in a series of prints under the wonderful title Le Ventiquattr'Hore dell'humana felicità www.ashmolean.org/collections-...)

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Stephen Johnston @stephenaj.bsky.social · 1d

Thanks for posting this link - that's really helpful, because I was thinking how unlikely it was I'd get to Nuremberg in the next 6 months....

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Stephen Johnston @stephenaj.bsky.social · 2d

And it proves that not all sundials from 1900 were either cloyingly moralistic ("remember the hour, for death is coming") or were laying on a fake "olde worlde" charm. This is a pretty fresh take (I think - not exactly my period).

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Stephen Johnston @stephenaj.bsky.social · 2d

Another distracting sundial! But the sun's rays marking out the hours, with an evening owl and a morning cockerel, are lovely. Not to mention the pharmacy's golden stock list - bandages, plasters, elastic stockings and even instruments (phew - the latter entirely justifying this mild diversion)

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Stephen Johnston @stephenaj.bsky.social · 2d

Wonderful that this medieval Merton-related astronomical manuscript could return to the college with FNL support!

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Stephen Johnston @stephenaj.bsky.social · 3d

Of course - who can ever have enough armillary spheres? Such an endlessly repurposed icon. And what on earth did it represent and mean for late C19 Belgians, compared to (say) in an ancient mosaic?
commons.wikimedia.org/wiki/File:So...

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Stephen Johnston @stephenaj.bsky.social · 4d

The ecliptic looks like it's at quite an exaggerated - if not downright jaunty - angle. But maybe Ghent is just that sort of town?

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Stephen Johnston @stephenaj.bsky.social · 6d

Hope you're better soon! In the mean time you might want to post a new profile picture as your Renaissance status update .... en.wikipedia.org/wiki/Wound_M...

Wound Man - Wikipedia

en.wikipedia.org

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Stephen Johnston @stephenaj.bsky.social · 9d

My final piece of hand engraving on copper, at the end of an excellent two-day course (online!). Various slips and scratches (some disguised by the blurry image) but the main point was to make me see better when I'm examining historical mathematical instruments. So much more to look out for now.

Small copper plate hand-engraved with a symmetrical decorative pattern. The visible metal surface is about 6cm square.

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Stephen Johnston @stephenaj.bsky.social · 18d

I'm afraid not: we reached capacity and closed sales this afternoon. Do keep an eye out for future events from the History of Science Museum

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Stephen Johnston @stephenaj.bsky.social · 19d

Rolling out the red carpet for Saturday's #astrolabe study day in #Oxford, here with Taha Yasin Arslan - freshly arrived from Istanbul Medeniyet University - to set up our metalworking stations. Files, fret saws, rivets and hammers at the ready!

Dr Taha Yasin Arslan standing in a hall on a red carpet surrounded by three tables with astrolabe parts, clamps and tools.

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Stephen Johnston @stephenaj.bsky.social · 20d

But it's also out in the wild in print - and arrived in Oxford literally this morning!

Front cover of book by Malcolm Walsby, "Entre l'atelier et le lecteur".

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Stephen Johnston @stephenaj.bsky.social · 21d

I recognise that! Can I ask how it differs from the original version?
(Hope that's not too distracting a question....)

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Stephen Johnston @stephenaj.bsky.social · 22d

Ugh, that's so ghastly and thoughtless - all power to you for calling it out here, and being clear on what's at stake. (And, for what it's worth, I for one am hugely looking forward to learning more from your research.)

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Stephen Johnston @stephenaj.bsky.social · 22d

The whole thread is wonderful and beautifully done but it's this photo which is the most amazingly eye-popping of them all - at least for someone who has worked and lived in Oxford for 30 years. Many thanks, and may more of your hours be boring if they illuminate like this!

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Stephen Johnston @stephenaj.bsky.social · 22d

And I did think about going indie and just getting my own domain name and making a site - I might even have done it 20 years ago when the web was a more innocent place. But I'm getting too old and impatient for server admin, WordPress updates and spam blocking....

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Stephen Johnston @stephenaj.bsky.social · 22d

My only hesitation with Knowledge Commons is that they lost a couple of grants in the DOGE cuts, and may be vulnerable to more unpredictable US policy shifts. Investing resources of time and energy in another platform that could be carelessly targetted doesn't exactly lighten my heart...

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Stephen Johnston @stephenaj.bsky.social · 22d

That looks like a nice profile page - from which I might take some cues. I set up my Knowledge Commons account more than a year ago, but hadn't got round to making a profile and populating the repository with texts that had been on Academia.edu (from which I also deleted my account a few days ago)

Academia.edu - Find Research Papers, Topics, Researchers

Academia.edu is the platform to share, find, and explore 50 Million research papers. Join us to accelerate your research needs & academic interests.

Academia.edu

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Stephen Johnston @stephenaj.bsky.social · 23d

And the explicit use of unequal hours for houses on a medieval instrument is important evidence - of just the kind I was thinking about in the recent "Back to the Future" piece - see note 8 in particular. (Helps to explain why unequal hours continue to appear on simplified astrological astrolabes.)

Stephen Johnston @stephenaj.bsky.social · 23d

Excellent. And I just looked more closely at the image and see that it's using every second unequal hour line for fixed houses (ie Ibn Ezra/Placidus). Which for me is brilliant - it makes the planicelium a different route of development for the simplified astrological astrolabe.

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Stephen Johnston @stephenaj.bsky.social · 24d

Not really my period, but perhaps this comes from McGuire and Rattansi, 'Newton and the "Pipes of Pan"' (1966): doi.org/10.1098/rsnr...

Newton and the ‘Pipes of Pan’ | Notes and Records of the Royal Society of London

doi.org

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