Stephen Johnston
@stephenaj.bsky.social
Curator Emeritus at Oxford's History of Science Museum; STEM historian, particularly instruments and material culture - current research focused on astrolabes and astrology in medieval and renaissance Europe. (Disclaimer: focus known to wander.)
Reposted by Stephen Johnston
Very excited to see the proofs of my newest (newest) article for this December’s issue of the Bulletin of the Scientific Instrument Society.
November 8, 2025 at 2:25 PM
Very excited to see the proofs of my newest (newest) article for this December’s issue of the Bulletin of the Scientific Instrument Society.
Short thread 🧵on the frequently invisible realm of #histsci connections, seen through the medium of #secondhand books – in this case one bought online which arrived in the post today.
#Hebrew #medieval #astronomy #tables
#Manchester
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#Hebrew #medieval #astronomy #tables
#Manchester
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November 7, 2025 at 9:29 PM
Short thread 🧵on the frequently invisible realm of #histsci connections, seen through the medium of #secondhand books – in this case one bought online which arrived in the post today.
#Hebrew #medieval #astronomy #tables
#Manchester
(1/4)
#Hebrew #medieval #astronomy #tables
#Manchester
(1/4)
Reposted by Stephen Johnston
Impossible to overstate how exciting field conferences are for academics. We spend 11.95 months a year with people only understanding 5-15% of our jokes and references, but then for three glorious days 😍😍😍
November 5, 2025 at 1:13 AM
Impossible to overstate how exciting field conferences are for academics. We spend 11.95 months a year with people only understanding 5-15% of our jokes and references, but then for three glorious days 😍😍😍
And now it's even in the Warburg's newsletter this morning - handily available at mailchi.mp/sas/news-fro... even for whose who're not subscribers (through why ever wouldn't you be?). You don't have to scroll down far for "In the Media".
November 5, 2025 at 1:48 PM
And now it's even in the Warburg's newsletter this morning - handily available at mailchi.mp/sas/news-fro... even for whose who're not subscribers (through why ever wouldn't you be?). You don't have to scroll down far for "In the Media".
Reposted by Stephen Johnston
🧵🧵In the very first instalment of this guest author and fellow stargazer 🤩💫and skywalker 🌌👣series, it is my pleasure to introduce Stamatina Mastorakou (@smasto.bsky.social), the October Cosmopoet! Here's what she had to share about her chosen poem:
Byzantine Silver Plate Depicting Aratus and Urania
This Byzantine silver plate is on view at the Institute as part of the exhibition "Time and Cosmos in Greco-Roman Antiquity".
isaw.nyu.edu
October 14, 2025 at 5:06 PM
🧵🧵In the very first instalment of this guest author and fellow stargazer 🤩💫and skywalker 🌌👣series, it is my pleasure to introduce Stamatina Mastorakou (@smasto.bsky.social), the October Cosmopoet! Here's what she had to share about her chosen poem:
Reposted by Stephen Johnston
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-...)
October 14, 2025 at 8:25 AM
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-...)
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.
October 5, 2025 at 5:49 PM
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.
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!
September 25, 2025 at 8:39 PM
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!
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.)
September 19, 2025 at 6:51 PM
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.)
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!
September 16, 2025 at 2:58 PM
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!
Just two weeks to go until the #Oxford #astrolabe study day on Saturday 27 September! Learn the making and use of this most iconic scientific instrument – with the bonus that everyone attending gets to assemble and take home their own modern laser-cut astrolabe.
September 14, 2025 at 10:10 AM
Just two weeks to go until the #Oxford #astrolabe study day on Saturday 27 September! Learn the making and use of this most iconic scientific instrument – with the bonus that everyone attending gets to assemble and take home their own modern laser-cut astrolabe.
It also made me look again at the Shah Abbas astrolabe in Oxford, from the first year of his rule, and therefore shortly before this astrologically overdetermined event.
August 24, 2025 at 10:12 AM
It also made me look again at the Shah Abbas astrolabe in Oxford, from the first year of his rule, and therefore shortly before this astrologically overdetermined event.
Very pleased to see them safely back on display, though it's been wonderful to have the chance to study them closely while the library refurbishment was underway - thanks so much for the opportunity!
Astrolabes and quadrants return to display in the Upper Library at Merton College with special thanks to Nikki Tomkins, Oxford Conservation Consortium, Khris Watts, Harriet Campbell Longley, and @stephenaj.bsky.social It took many hands! #astronomy #astrolabes
August 15, 2025 at 3:56 PM
Very pleased to see them safely back on display, though it's been wonderful to have the chance to study them closely while the library refurbishment was underway - thanks so much for the opportunity!
Paging #medieval #palaeography for an unfamiliar abbreviation of XL on an astrolabe at Merton College Oxford. Does this ring any bells in terms of date or place for @sebfalk.com or @eleonoraandriani.bsky.social? Or anyone else you can think of? (There’s nothing obvious in Cappelli online.)
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July 7, 2025 at 11:25 AM
Paging #medieval #palaeography for an unfamiliar abbreviation of XL on an astrolabe at Merton College Oxford. Does this ring any bells in terms of date or place for @sebfalk.com or @eleonoraandriani.bsky.social? Or anyone else you can think of? (There’s nothing obvious in Cappelli online.)
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A generous loan from the Qatar National Library has extended the scope of the Lines of Faith exhibition - so it now includes astrolabe manuscripts. It's also extended in time, running until mid-October. Many thanks to the OCIS Librarian Wassilena Sekulova for masterminding the complex logistics!
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July 2, 2025 at 12:53 PM
A generous loan from the Qatar National Library has extended the scope of the Lines of Faith exhibition - so it now includes astrolabe manuscripts. It's also extended in time, running until mid-October. Many thanks to the OCIS Librarian Wassilena Sekulova for masterminding the complex logistics!
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Good to see that, heatwave or not, my DIY "portable" Roman sundial is still working fine. I simply suspended the dial and turned it so that the shadow of the gnomon was exactly on the hour scale. At 07.20 British Summer Time we were already half way through the second seasonal (unequal) hour.
July 1, 2025 at 7:20 AM
Good to see that, heatwave or not, my DIY "portable" Roman sundial is still working fine. I simply suspended the dial and turned it so that the shadow of the gnomon was exactly on the hour scale. At 07.20 British Summer Time we were already half way through the second seasonal (unequal) hour.
A short thread starting from the published version of this piece on astrolabes, astrology and their digital representation and capture. “Starting from” rather than simply “restating” the article’s main points because it wasn’t intended to be the last word on its topic.
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New publication! Late last year I gave the Scientific Instrument Society's annual lecture. The written version of "Back to the Future: New Approaches to the Astrolabe" is now printed in the SIS Bulletin, but currently available as a free download at
scientificinstrumentsociety.org/BulletinArti...
scientificinstrumentsociety.org/BulletinArti...
June 22, 2025 at 3:37 PM
A short thread starting from the published version of this piece on astrolabes, astrology and their digital representation and capture. “Starting from” rather than simply “restating” the article’s main points because it wasn’t intended to be the last word on its topic.
(1/7)
(1/7)
New publication! Late last year I gave the Scientific Instrument Society's annual lecture. The written version of "Back to the Future: New Approaches to the Astrolabe" is now printed in the SIS Bulletin, but currently available as a free download at
scientificinstrumentsociety.org/BulletinArti...
scientificinstrumentsociety.org/BulletinArti...
June 22, 2025 at 9:21 AM
New publication! Late last year I gave the Scientific Instrument Society's annual lecture. The written version of "Back to the Future: New Approaches to the Astrolabe" is now printed in the SIS Bulletin, but currently available as a free download at
scientificinstrumentsociety.org/BulletinArti...
scientificinstrumentsociety.org/BulletinArti...
Reposted by Stephen Johnston
These are great - thanks! Despite the difficulties of photography through showcase glass I can't resist sharing a detail of just how crisply you've captured the engraving and the throne. (Hope that's OK....)
June 15, 2025 at 5:19 PM
These are great - thanks! Despite the difficulties of photography through showcase glass I can't resist sharing a detail of just how crisply you've captured the engraving and the throne. (Hope that's OK....)
Reposted by Stephen Johnston
PS if you're actively looking at astrolabes you might find yourself seriously distracted. Have you seen those by the Arsenius workshop and also by Habermel where the throne is attached to the rim by screws? Louvain and Prague, rather than Nuremberg but still pretty close to home.....
June 14, 2025 at 6:07 PM
PS if you're actively looking at astrolabes you might find yourself seriously distracted. Have you seen those by the Arsenius workshop and also by Habermel where the throne is attached to the rim by screws? Louvain and Prague, rather than Nuremberg but still pretty close to home.....
Thanks for the pictures Eleonora. I have more images coming from different days, but it's been such an intense week that my BlueSky capacity failed after day 1! I'm sure normal service will be resumed soon....
2025: Training week: A global History of Astronomy on Primary Sources: new approaches, new digital tools
Just a few photos from the first two days @cosmopoet.bsky.social @stephenaj.bsky.social @tur-alexandre.bsky.social @labnf.bsky.social @obs-paris-psl.bsky.social @irht-cnrs.bsky.social
Just a few photos from the first two days @cosmopoet.bsky.social @stephenaj.bsky.social @tur-alexandre.bsky.social @labnf.bsky.social @obs-paris-psl.bsky.social @irht-cnrs.bsky.social
June 5, 2025 at 3:37 PM
Thanks for the pictures Eleonora. I have more images coming from different days, but it's been such an intense week that my BlueSky capacity failed after day 1! I'm sure normal service will be resumed soon....
Reposted by Stephen Johnston
Anuj Misra and Agathe Keller led us through Sanskrit astronomy and mathematics, with beautiful astrological charts - prefaced and supported by curator Jerome Petit, who had the final task of rolling back up the 37m (!) scroll, bit by bit.
June 2, 2025 at 7:04 PM
Anuj Misra and Agathe Keller led us through Sanskrit astronomy and mathematics, with beautiful astrological charts - prefaced and supported by curator Jerome Petit, who had the final task of rolling back up the 37m (!) scroll, bit by bit.
On commence! Kicking off the Paris training week in global history of astronomy at @labnf.bsky.social with Matthieu Husson and Alexandre Tur @tur-alexandre.bsky.social. More at eida.hypotheses.org/seminars-2/t...
June 2, 2025 at 7:17 AM
On commence! Kicking off the Paris training week in global history of astronomy at @labnf.bsky.social with Matthieu Husson and Alexandre Tur @tur-alexandre.bsky.social. More at eida.hypotheses.org/seminars-2/t...
Reposted by Stephen Johnston
Thank you to Angela Axworthy and @thomas-morel.bsky.social for organising a great meeting. Come for Euclid and practical geometries, and stay for Wuppertal's immortal Schwebebahn!
May 24, 2025 at 8:24 AM
Thank you to Angela Axworthy and @thomas-morel.bsky.social for organising a great meeting. Come for Euclid and practical geometries, and stay for Wuppertal's immortal Schwebebahn!
Missing from the line-up (and without even a selfie) was your own "From Euclidean Geometry to Field Theory: Surveying Practices in the Textbooks of J.F. Penther (1732) and A. Böhm (1759)" - a fascinating comparative case of generational change in university teaching. More of this, please!
Philip Beeley discusses Euclid and the London Mathematicians, 1650-1730, their responses to Oxford's grand new plan for a critical of Euclid, and their own 📖 as teachers and practitioners !
May 22, 2025 at 8:50 PM
Missing from the line-up (and without even a selfie) was your own "From Euclidean Geometry to Field Theory: Surveying Practices in the Textbooks of J.F. Penther (1732) and A. Böhm (1759)" - a fascinating comparative case of generational change in university teaching. More of this, please!