A large sunspot dominates the frame, a dark irregular core with lighter veining and a trailing cluster of smaller spots against the mottled, granular surface of the sun's photosphere. The caption identifies the site as McDonald Observatory in Fort Davis, Texas. The observatory opened in 1939 on Mount Locke in the Davis Mountains, and its telescopes were used for solar and stellar research. Images of the sun's surface like this one served both scientific study and public education about astronomy.
White border around a glossy black-and-white photographic print; two-line printed title caption below photo: 'A Large Sun Spot / McDonald Observatory, Fort Davis, Texas.'
No postmark. Real-photo Kodak paper back with 'PHOTO POST CARD' and Angeleno Photo Service imprint; divided back, white border, glossy; blank address/message; light edge wear.
Cite this card
Large sunspot, McDonald Observatory, Fort Davis, TX, circa 1939, postcard, c. 1939. PostalPast Collection. https://postalpast.com/postcard/large-sunspot-mcdonald-observatory-fort-davis-tx-circa-1939. Accessed November 2, 2026.
