Engraved plate from a 18th century book, showing on the left the detailed drawing of an armillary sphere, with many points labeled, on the upper right the drawing of a circular horizontal sundial, and on the lower right the drawing of a circular vertical sundial. Both sundials are surrounded by a sphere with circles (meridians) much like the armillary sphere, to explain the hour lines from the sphere.

Explaining the hour lines of the horizontal and the vertical #sundial (on the right) by comparing to the circles of the armillary sphere (drawn on the left).
By James Ferguson in 'Lectures on select subjects' (1775), chapter 'Dialling'.
🔭 #histsci #astrohistory

Williamina Fleming: Early life and introduction to Edward Pickering

A brief article on Williamina Fleming, co-written by one of the former Harvard research professionals who helped me with my novel about the Scottish-American maid who became an astronomer
www.aip.org/history/will... #WomenInSTEM #Astronomy #astrohistory

Highly recommended!
#astrohistory #histsci #medievalsky

An old brown square paper with a disc carrying several circular scales. Two smaller discs with indexes can be rotated. The indexes are labeled 'Sun's Index' and 'Moon's Index'. Credits for all images: Daniel Crouch rare books.

Back of the previous item, title 'The Luminarium', with 3 arcs carrying numbers (days of the month; week days, age of the Moon. Below a text provides a guide for these scales and the back.

🔭 🧪 #astrohistory
James Ferguson's 'Luminarium', a very rare card #volvelle (~1760).
For any date, the volvelle provides the duration of the semi-diurnal arc, or half-length of the day, from which you can find the sunrise/sunset times (for London) by adding or substracting from noon.

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John Churchman, The magnetic atlas; or, Variation charts of the whole terraqueous globe, comprising a system of the variation and dip of the needle, by which, the observations being truly made, the longitude may be ascertained. Planche I. 1794. The Royal Society, RCN 33275

#maps #carto 🔭 #astrohistory
Exposition : "La figure de la Terre. Un débat scientifique franco-anglais (XVIIᵉ-XXIᵉ siècle)", par l'Académie des Sciences et la Royal Society.

À la bibliothèque Mazarine (Paris), 1-20 juin 2026.

www.academie-sciences.fr/exposition-l...

Oh, just saw that both volumes are already available #OA on the project page.

ptolemaeus.badw.de/publications

#astrohistory #histsci #medievalsky

#astrohistory #histsci #medievalsky

Photo of an old sheet of paper, title 'The Analemma Improved by B Donn, Bristol. Published by the Author Jan.1st 1770. Upper part: a half circle grid representing a (celestial) sphere, with a half circle scale in degrees. Lower part: several scales, including a calendar. Lower center: a table with star names and their coordinates.

Here's Benjamin Donn's 'Improved Analemma' (1770, Bristol).
Can be used at any latitude to find the sunrise/sunset times, elevation, solar time, as well as the rising, setting & southing of stars.

🔭 🧪 #EduSky #astrohistory

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🔭 #astrohistory

Large engraved celestial chart, richly coloured, with a rotating printed paper ring. Civil and zodiacal calendars on the rim. Constellations depicted as animals or mythological figures.

🔭 #astrohistory
Paper star chart by Claes Jansz Vooght (The Nederlands, ~1680).
The chart shows the stars visible from 52° latitude . The carved yellow volvelle rotates in order to indicate the part of the sky visible at a particular moment. Oval: local horizon, with bearings (North, N east...).

Wow!
#booksky #astrohistory

#astrohistory 🔭

This is truly a loss for #histsci #astrohistory. His “On Both Sides of the Strait of Gibraltar” summarizes the current state of research on many questions.
brill.com/display/titl...

A circular chart with several scales on the rim, on an old paper. Symbols for lunar phases. A star chart visible through an oval opening near the center.

🔭 #astrohistory
The 'New Astronomical Instrument', by 🏴󠁧󠁢󠁳󠁣󠁴󠁿 James Ferguson (~1750). A paper model. #volvelle

A star chart is visible through the oval opening which represents the horizon for the latitude of London.
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FOUND: Neil Armstrong’s Secret Stash & The Challenger Wreckage Neil Armstrong was the ultimate rule follower. So why did he hide a bag of "stolen" moon gear in his closet for 40 years? Space history is usually written in textbooks, but sometimes, it’s found in a dusty closet or at the bottom of the ocean. In this episode, we explore the incredible stories of lost space relics that resurfaced decades later to rewrite history. We start with the secret life of Neil Armstrong. After his passing, his widow Carol discovered a white stowage bag—known as the McDivitt Purse—hidden in their home. Inside wasn't just junk; it was the 16mm Data Acquisition Camera that filmed the lunar landing—a priceless artifact that was technically supposed to be left on the Moon to save weight. Why did he keep it? And how did he get it back to Earth? Then, we fast forward to the haunting 2022 discovery off the Florida coast. We discuss how divers searching for WWII planes accidentally found a massive segment of the Space Shuttle Challenger, resting on the ocean floor since the 1986 tragedy. As we approach the 40th Anniversary of the Challenger disaster, we examine the emotional weight of these artifacts. From "contraband" souvenirs to tragic debris, these objects bridge the gap between the stars and the human experience. In this episode, we uncover: - The Armstrong Secret: The contents of the hidden Apollo 11 purse. - The Rules of Weight: Why NASA wanted that camera left on the Moon. - The Challenger Find: How a TV crew found the shuttle 36 years later. - The Legacy: What these objects tell us about the cost of exploration. 🎧 Press play to uncover the secrets NASA didn't put in the museum. Did this story give you chills? Please hit the Follow button and leave a 5-star review! Share this with a history buff who thinks they know everything about Apollo 11—we bet they don't know this.

📣 New Podcast! "FOUND: Neil Armstrong’s Secret Stash & The Challenger Wreckage" on @Spreaker #40thanniversary #apollo11 #artifacts #astrohistory #astronomy #challengerdisaster #historyfacts #lostandfound #moonlanding #mystery #nasa #neilarmstrong #oceandiscovery #podcast #science #spacehistory

Thanks, @enniusredloeb.bsky.social!
A good opportunity to mention this important book:
Islamicate Celestial Globes: Their History, Construction, and Use by Emilie Savage-Smith.
#histsci #astrohistory
repository.si.edu/items/0d9cfc...

Photo of an ivory foldable sundial, shaped as a mandolin, with a string attached between the 2 parts. Hour lines radiating from the attaching points. A small compass is nested in a hole. Credit: "Galerie Delalande Paris"

Other view of the same object, folded. Decorated with flourishes, and parallel lines carved as strings. Credit: "Galerie Delalande Paris"

A diptych #sundial, shaped as a mandolin.
Nurenberg, 1st half of 17th century. 7.5cm long.
The magnetic compass has been very useful for portable sundials, especially in mid-17thc. in Europe when the magnetic and geographic poles were in the same direction.
🔭 #astrohistory

A square paper sheet with several circular diagrams, on old paper. An vintage Sun-face drawing at the center. Credit: British Library, public domain.

Detail from the previous photo, with some of the round scales, calendar, zodiacal calendar, new moon and full moon symbols.

The 'Astronomical Rotula', a paper tool for predicting the dates of eclipses for the next decades.
Made of 5 rotating discs. Invented 1739 by 🏴󠁧󠁢󠁳󠁣󠁴󠁿 James Ferguson, who would become famous for his lectures, models and popular books in astronomy, mechanics and electricity.
🔭 #astrohistory #EduSky
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Vol. 22 (2025) | Suhayl. Journal for the History of the Exact and Natural Sciences in Islamic Civilisation

The new volume 22 (2025) of Suhayl. International Journal for the History of the Exact and Natural Sciences in Islamic Civilization.

#histsci #astrohistory #medievalsky

revistes.ub.edu/index.php/su...

#astrohistory

My digital version of this astronomical tool is now available for printing (5 pages, preferably card stock).
If you can read french, or if you can have it translated, there's also a user guide. This 1778 tool was designed to find longitude with stars and a watch.
🔭 #astrohistory
shorturl.at/bvgYd

🔭 #astrohistory

#medievalsky #histsci #astrohistory #historyofastronomy #astrolabes

photo of a square sheet of paper, old and orange, with a circular star chart, circular scales all around and a pivoting ruler. Some astronomical old style drawings on top and bottom. Title in french "Planétaire ou planisphère nouveau, inventé et dessiné par M. Flécheux".

Close up on the 3 wheels, each with 1 or 2 circular scales.

🔭 #astrohistory
This is the "Planétaire ou planisphère nouveau" by M. Flécheux (1780).
A paper (or cardboard) astronomical instrument, with which you can derive some astronomical parameters.
Background: a star chart and a calendar, a pivoting ruler carrying scales and a set of 3 rotating wheels.
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www.youtube.com/watch?v=wS7a... Happy birthday to the Astro single "Blue Flame" #Astro #AstroHistory #BlueFlame

Physicists and philosophers have long struggled to understand the nature of time: Here’s why How can time feel so obvious, so woven into the fabric of our experience and yet, for thousands of years, remain the bane of every thinker who has tried to explain it?

My third article on time/spacetime is live.
It isolates the precise category error behind 2,500 years of confusion about time — and shows why the problem finally dissolves once that mistake is fixed.
theconversation.com/physicists-a...
#cosmology #philsci #histsci #astrohistory

Elias Allen and the role of instruments in shaping the mathematical culture of seventeenth-century England Elias AlIen (c.1588-1653) was known as the best mathematical instrument maker of his day. He lived and worked in London, creating a thriving business - he was the first English instrument maker to sup...

Dr. Hester Higton wrote a PhD thesis about Elias Allen. Her work can be found here:

#astrohistory 🔭

www.repository.cam.ac.uk/items/5e94c4...

Yes - a lot of firsts - It was amazing for sure!

Also took a 'family portrait of the Solar System' from 6 billion km (Voyager 1, 1990).
Earth is just one pixel (Pale Blue Dot image), but the whole 60 image mosaic shows all of Venus, Earth, Jupiter, Saturn, Uranus, Neptune

#AstroHistory

Voyager 1 reveals Io erupting — 9 active volcanoes, 300 km plumes, lava lakes. Io was the first body beyond Earth seen with live volcanism. Linda Morabito spots the plume in a nav image.
Image: Loki plume, NASA/JPL
#AstroHistory #Jupiter

#histsci #astrohistory