Late 19th century lantern slide of the 26-inch "Great Equatorial" refractor telescope at the Old Naval Observatory in Foggy Bottom. When acquired by the Navy in 1873, it was the largest refracting telescope in the world. https://t.co/EzOhxcptcd Late 19th century lantern slide …
— Kenneth Samson (@PangurBanC) Jan 20, 2022
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January 20, 2022 at 09:22AM
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