Unused 1930s California glossy real photo postcard split between exterior and interior close-up views of the 100" Hooker Telescope on the grounds of the Mount Wilson Observatory - located on Mount Wilson, a 5,715 foot peak in the San Gabriel Mountains near Pasadena, northeast of Los Angeles. Mount Wilson Observatory - with its 60-inch and 100-inch telescope, and 60-foot and 150-foot tall solar towers - is the astronomical center of Southern California. On the lower border are the printed captions "100" Telescope" and "Mt. Wilson Observatory".

The observatory was conceived and founded by George Ellery Hale and funded by the Carnegie Institute in 1904, which originally leased the land for 99 years from the owners of the Mount Wilson Hotel. In 1917 the 100" Hooker Telescope became operational and would be the world's largest telescope until the opening of the 200" Mount Palomar Hale Telescope in 1948. Edwin Hubble arrived at Mount Wilson in 1919 and, throughout the 1920s, made many astronomical discoveries using the Hooker Telescope. The observatory is still used for astronomical study, and is open for public tours.

Chloride print (sepia-toned) glossy real photo postcard, collected unused by a Connecticut couple on an extended touring vacation through the West in 1937 – and only recently removed from their vacation memory album where it has been for over 70 years. There is no publisher or photographer's imprint. This postcard has an EKKP (1914-1950) photo paper stamp box imprint, and was published sometime between the construction of the telescope in 1917 and its 1937 purchase date. However, postcards with white borders surrounding the image usually were published prior to 1931.

The images are both glossy, quality photos. Over time, there has been some slight fading along the borders, which is less noticeable in person than in these photos. This is a natural aging process for many glossy chloride print real photos. Otherwise, the card is in great condition, with no tears or folds. Some light soiling and wear around the edges from handling, but the images are not involved. Corners are only slightly blunted.