Stephen Johnston

@stephenaj.bsky.social

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Curator Emeritus at Oxford's History of Science Museum, with interests in instruments and material culture. Current research focus on armillary spheres and astrolabes in medieval Europe. (Disclaimer: focus known to wander.)

A cotton-gloved hand holds a silver circular disc, itself part of a larger astronomical compendium. The volvelle disc carries an engraved zodiac-calendar scale and two independently rotating discs, one with a sun pointer underneath a smaller disc with a moon pointer. The centre of the moon disc has an astrological aspectarium and a window to show the phase of the moon. Beyond a hinge, a part of another circular face of the instrument is visible.
Two small circles punched on brass.
Punched Latin text on brass: sub equa[tore].
An apparent emoji face on the brass surface of a small tab in a 15th-century astrolabe.
Detail of the back of a brass astrolabe with the arcs and lines of a trigonometric quadrant and the richly decorative calligraphy of a set of semicircular tables.
Detailed view of part of a brass celestial globe showing constellations, stars and the graduated arcs of the ecliptic and equator, with a horizon and meridian ring.
Printed image of a semicircular measuring instrument with a compass rose and a fixed and a rotating alidade, sitting on a chequered floor against a blank background with Chinese text.
Printed image on paper of a celestial globe in a horizon ring sitting on a chequered floor against a blank background with Chinese text. Above the printed image is a manuscript annotation in French. From Ferdinand Verbiest's series of prints "Xinzhi Yixiangtu" ("pictures of newly-made instruments").
Circular diagram on paper with fold marks. The outer rings of the circle are lettered in black ink and the inner in red.
Printed diagram in the shape of an egg with planetary orbs
Fortification diagram from Donato Rossetti, Fortificazione a rovescio (Turin 1678), from https://babel.hathitrust.org/cgi/pt?id=gri.ark:/13960/t6rz6j63z&seq=5&view=1up
Ochre-coloured bound volume standing upright on a desk.
Bound volume of 1957 auction catalogues in front of an (older?) 20th-century light switch
View of the first reading room of the National Art Library, London with desks and a gallery of books; image from https://www.vam.ac.uk/info/national-art-library
Two pairs of large parchment diptychs on a reading room desk.
Image taken from Alex Boxer's online astrolabe https://alexboxer.com/astrolabe/ showing the sky for 15 November 1577 at the latitude of Antwerp, with the sun having just set, Gemini rising, the Moon visible in Aquarius and Capricorn just past the meridian.
Clock dial face with cherub heads with wings in the spandrels. Movement of a long case clock by Ahasuerus Fromanteel, London, c. 1665 in the collection of HSM Oxford: https://hsm.ox.ac.uk/collections-online#/item/hsm-catalogue-5738.
Outer face of a diptych dial by Leonhart Miller, Nuremberg, 1636 with compass rose and wind names surrounded by wind heads. (Harvard Collection of Historical Scientific Instruments, https://chsi.emuseum.com/objects/1/rectangular-ivory-diptych-sundial)
Front cover of hardback book on 15th-century Viennese astronomer/astrologer Johannes von Gmunden (ed. Simek/Klein, 2012).
The table of oblique ascensions from Goldstein’s edition of the Astronomical Tables of Levi ben Gerson.
Flyleaf of a copy of Goldstein’s edition of the Astronomical Tables of Levi ben Gerson with the author’s handwritten dedication.
Title page of Bernard R. Goldstein, The Astronomical Tables of Levi ben Gerson (1974), with facing frontispiece reproduction of a Hebrew manuscript with a numerical table.
Yellow bookmark from Salsus Books in Kidderminster.
Detail of circular scales and colourful enamelled decoration on the planetary clock of Elector August, Dresden MPS, with later engraved identification of Venus.
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.
Small copper plate hand-engraved with a symmetrical decorative pattern. The visible metal surface is about 6cm square.
Dr Taha Yasin Arslan standing in a hall on a red carpet surrounded by three tables with astrolabe parts, clamps and tools.
Front cover of book by Malcolm Walsby, "Entre l'atelier et le lecteur".
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)
Set of tools and materials for hand engraving laid out on an oil cloth
A prototype version of a modern astrolabe designed and produced by Kevin Karney, pinned together with cocktail sticks and held up by string.
Astrolabe from the Khalili collection: https://www.khalilicollections.org/collections/islamic-art/khalili-collection-islamic-art-planispheric-astrolabe-sci430/
Tablet of horizons from the same astrolabe.
Detail of the back of the same astrolabe, with the inscriptions تحافر ذلك في أيام معدلت السلطان الأعظم والخاقان المعظم مولى ملوك الترك والعرب والعجم سلطان سلاطين الآفاق ومالك رقاب الأمم بالأستحقاق شاه عباس الصفوي الحسيني بهادر (بهاذر؟) خان خلد الله ملكه وسلطانه في تأريخ سنة ست وتسعين وتسعماية "I engrave this in the time of the just sultan, the greatest, the glorified Khāqān, master of the sovereigns of the Turks, the Arabs, the Persians, legitimately the sultan of the sultans of the horizons, and master of the necks of the nations, Shāh ʿAbbās, the Safawid, the Husainite, Bahādur Khān. May God make eternal his sovereignty and his power, in the year 996". Engraved on the back in the upper right quadrant. لا زالت ألوية دولته الأدبية مرفوعة يتأييد الحضرة الرفيعة المنيعة الملكية الأعظمية العادلية القهرمانية المرشدية الخانية ضمن الله معدلته بنظام أحوال المسلمين بالطاف الصمدانية "The flags of his eternal nation have not ceased to be raised by the support of the august Majesty, powerful, royal, great, leonine, who shows the right way, the Khān. May God maintain his justice by the order of the states of the Muslims by divine favours". Engraved on the back, sideways on the right side, spanning the upper and lower halves. راقم الخطوط والدوائر والرقوم محمد أمين بن أميرزا خان النخعي ثم القمي حامداً مصلياً "The delineator of the lines, circles and numerals is Muḥammad Amin ibn Amirza Khan al-Nakhi, then al-Qummī, praising and praying." Engraved on the back on the lower right.
Detail of the rete of an astrolabe by Muhammad Amin ibn Amirza Khan an-Nakha`i for Shah Abbas, 1588: https://hsm.ox.ac.uk/collections-online#/item/hsm-catalogue-2107
Astrolabe plate for latitude 42° from Latin Spain, with three instances of an abbreviation for Roman numeral 40.
Detail of a latitude plate of a medieval astrolabe at Merton College Oxford, with the inscription CLIMA· III XXX
Detail of a latitude plate of a medieval astrolabe at Merton College Oxford, with the inscription CLIMA· V LATITVDO·XLI.
Detail of a latitude plate of a medieval astrolabe at Merton College Oxford, showing the numbering of the almucantar lines in Roman numerals, with an unusual abbreviation for 40.
Qibla diagram from chapter 35 of Fifty Chapters for the Ruler on the Science of the Astrolabe (Panjah Bab-i Sultani dar Marifat Usturlab) by Rukn al-Din b. Sharaf al-Din al-Husayni al-Amuli. Qatar National Library, HC.MS.2017.0057, f. 147.
A display showing three leaves from Fifty Chapters for the Ruler on the Science of the Astrolabe (Panjah Bab-i Sultani dar Marifat Usturlab) by Rukn al-Din b. Sharaf al-Din al-Husayni al-Amuli. Qatar National Library, HC.MS.2017.0057.
Two showcases with manuscripts from the Qatar National Library, with an animated astrolabe projection between them.
Wooden version of a Roman sundial displaying the time in unequal hours. It has been set up for the latitude of Oxford and for the sun's declination (just beyond the solstice), and the shadow of the gnomon falls roughly half way between 1 and 2 on the hour scale.
Detail from the Johannes Schöner terrestrial globe of 1520, seen in 2023 at the Germanisches Nationalmuseum, Nuremberg.
Small equinoctial sundial, closed to show lid with Gothic inscriptions, in the Landesmuseum Württemberg
Instrument catalogued as "Fake? Astrological Astrolabe" at https://hsm.ox.ac.uk/collections-online#/item/hsm-catalogue-2078
Manuscript astrological astrolabe by Hanns Herghamer, 1492, at the History of Science Museum, University of Oxford https://hsm.ox.ac.uk/collections-online#/item/hsm-catalogue-9231
Cartoon image of Homer Simpson suffering a “D’oh!” moment.
Johanna Garzon, Afra Akyol and Maedeh Hosseinzadeh presenting on astrolabes at the Paris Observatoire.
Handcoloured paper astrological astrolabe pasted onto the inside of the wooden back cover of the “Heidelberger Schicksalsbuch” (Book of Fate), dating from after 1491. Universitätsbibliothek Heidelberg, Cod. Pal. germ. 832 (http://digi.ub.uni-heidelberg.de/diglit/cpg832/0560).
Juxtaposition of two (half-)latitude plates for 51° from two different astrolabes. On the left from a typical medieval European instrument from the workshop of Jean Fusoris (c. 1400) and on the right from a simplified astrological astrolabe signed by Johannes Wagner in 1538 (both at the History of Science Museum, Univesity of Oxford).
Gilt brass base for a cylinder dial (HSM Oxford inv. 13616).
Detail of months and zodiac symbols from a cylinder dial in Oxford (HSM inv. 13616).
Handle of a Deutsches Museum nocturnal with zodiac signs and length in days of corresponding months
Ivory, wood and brass cylinder sundial
Zodiac signs on the scale of an early form of equinoctial ring dial; https://hsm.ox.ac.uk/collections-online#/item/hsm-catalogue-1983
Comparative figure showing the appearance of 9 zodiac signs by 4 different Elizabethan makers. From Gerard Turner, Elizabethan Instrument Makers (2000).
Detail of part of a latitude plate and rete of the astrolabe by Gerard Mercator in Augsburg
Detail of the front of an astrolabe by Gerard Mercator on display in Augsburg
Detail from astrolabe signed by Regnerus Arsenius 1565, highlighting the screw heads attaching the throne to the mater; HSM Oxford https://hsm.ox.ac.uk/collections-online#/item/hsm-catalogue-2030