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Stephen Johnston @stephenaj.bsky.social · 8m

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

Stephen Johnston @stephenaj.bsky.social · 2d

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 · 11d

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 · 12d

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 · 14d

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 · 15d

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 · 15d

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 · 15d

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 · 15d

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 · 15d

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 · 15d

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 · 17d

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 · 17d

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 · 17d

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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Stephen Johnston @stephenaj.bsky.social · 18d

I hope there will be spare planicelia available afterwards for those with high-maintenance astrolabe needs....

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Stephen Johnston @stephenaj.bsky.social · 18d

Oh no - my FOMO button has been activated!

Especially because the planicelium seems to be a cute baby astrolabe that hasn't yet grown out to the tropic of Capricorn, and is still a toddler at the equator. I look forward to @sgessner.bsky.social telling us more (and proving my rash verdict wrong?)

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Stephen Johnston @stephenaj.bsky.social · 18d

I also hope it might support some meta-reflection: I’m looking forward to a fruitful collision between Pamela Smith’s notions of embodied knowledge and artisanal epistemology and the experience of being taught manual skills via Zoom. Wish me luck!

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Stephen Johnston @stephenaj.bsky.social · 18d

This is ahead of an introductory online course in a fortnight. I hope it will make me better appreciate and interrogate historical instrument engraving - though I'm not expecting to display my new-found abilities any time soon.

Detail of the engraving of Libra and a scale on an astronomical compendium attributed to Hans Dorn, 1481 (HSM Oxford inv. 43055: https://hsm.ox.ac.uk/collections-online#/item/hsm-catalogue-2953)

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Stephen Johnston @stephenaj.bsky.social · 18d

Deciding I might as well embrace my new status as “unfunded hobbyist researcher” (sorry: UK-only in-joke), so here's my new kit just arrived from the Hand Engravers’ Association. (I had to supply my hand measurement so that the burin/graver could be made to the right size.)

Set of tools and materials for hand engraving laid out on an oil cloth

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Stephen Johnston @stephenaj.bsky.social · 19d

I look forward to seeing the published version of this. Can I ask how soon "very soon" was when you wrote this 6 months ago? (I've been revisiting R.T. Gunther's century-old idea of an archaeology of science for a paper at the upcoming Beyond Books conference arthist.net/archive/49357.)

Beyond Books: Instruments and Knowledge in Libraries (Geneva, 14-15 Jan 26)

Rossella Baldi, History Department. Geneva, Musée d'histoire des sciences, 14.–15.01.2026, Eingabeschluss : 15.06.2025

arthist.net

Stephen Johnston @stephenaj.bsky.social · 19d

Catching up with this thread again after many months - do you have the reference for the Rennes example, and can anything be shared about what went into the Troyes exhibition? Thanks in advance!

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Stephen Johnston @stephenaj.bsky.social · 21d

Sitting around chatting when you could have spent all day instead in zealous immobility in the silence of the libray? Sounds like you're overestimating the degree to which you were misfits! 😄

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Stephen Johnston @stephenaj.bsky.social · 21d

Thanks for posting this: nothing like a midnight book talk to pass the time! But it's only 11pm for me, so I've registered (and I'd get chucked out of a pub by then anyway 😄)

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Stephen Johnston @stephenaj.bsky.social · 22d

Participants even get their own customised astrolabe! One for @oxmedstud.bsky.social ? Details and tickets at www.eventbrite.co.uk/e/ingenuity-...

Ingenuity and Beauty: astrolabe study day

An exceptional opportunity to understand the making and use of the most iconic of medieval scientific instruments.

www.eventbrite.co.uk

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Stephen Johnston @stephenaj.bsky.social · 22d

Ever wondered what Chaucer’s clerk Nicholas would get up to with his astrolabe in the Miller’s Tale? In 10 days there’s a chance to learn about and make this most iconic #medieval instrument at a study day at the #Oxford Centre for Islamic Studies. Literally #MedievalSky!

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