61. Observatory, Mt. Holyoke College, South Hadley, Mass. Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–January 14, 1910] Institution: Anna Maria College
62. Observatory, Ohio State University, Columbus, Ohio Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
63. Observatory, Ohio Wesleyan University, Delaware, Ohio Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–July 1912] Institution: Anna Maria College
64. Observatory, Princeton University, Princeton, N.J. Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–November 19, 1906] Institution: Anna Maria College
65. The observatory, Smith College, Northampton, Mass. Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
66. The observatory, University of Minnesota Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–June 1907] Institution: Anna Maria College
67. Observatory, Vassar College, Poughkeepsie, N. Y. Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
68. Observatory, Vassar College, Poughkeepsie, N. Y. Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
69. Observatory, Washburn College, Topeka, Kan. Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–June 15, 1914] Institution: Anna Maria College
70. Observing station, High Altitude Observatory, University of Colorado Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
71. Palomar Observatory Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
72. Palomar Observatory, Palomar Mountain, California Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
73. Palomar Observatory, Palomar Mountain, California Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
74. Palomar Observatory, San Diego County, California Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–November 29, 1938] Institution: Anna Maria College
75. Palomar Observatory, San Diego County, California Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
76. Palomar Observatory, San Diego County, California--40 Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
77. Peking, observatory Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1914] Institution: Anna Maria College
78. Perkins Observatory, O.W.U., Delaware, Ohio Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
79. The Ritter Observatory & Planetarium Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College
80. Royal Observatory, Greenwich Format: Postcards/Cards Collection: Travel Postcards of Charles Blumsack Date: [ca. 1906–1996] Institution: Anna Maria College