1953 January 10, California, MA1 423
From Project Blue Book, labeled as Unidentified.
“On 10 January 1953, between 3:45 and 4:00pm, Col. ______ and Mr. ______ of the Federal Security Agency, San Francisco, California, observed and unidentified flying object while eight miles northwest of Sonoma, California, from a knoll in the hills northwest of the Sonoma Valley. The object was sighted at a 45° angle northwest from the location of the observers at a very high altitude, so high that the object was compared to the flat head of a pin held two feet from the eye. Speed was estimated at four times the speed of a jet aircraft with accompanying sound similar to the USAF F-86 jet at high altitude. There was no change in sound tone or volume during maneuvers. Unusual maneuvers made by the object were: 1. Three 360° tight turns to the right, taking two to three seconds to complete each turn; 2. two right angle turns, first to the right, then to the left; 3. the object slowed down to almost a complete stop, then accelerated to high speed again, making this maneuver twice. The object then rose vertically and disappeared from view. Total time of obseration was estimated to be between 60 and 75 seconds. There were no radar contacts with the object. No other observations of this object are known to have been made.
The object made three 360° turns to the right taking two to three seconds to complete each turn. These turns were made at five-second intervals still holding on the same course. It continued on and made an abrupt right-angle turn to the right, followed five seconds later with an abrupt turn to the left which placed the object back on its original course. After this maneuver, the object slowed down to almost a stop and then accelerated to its previous speed, making this maneuver twice. The object rose vertically and disappeared from view. [The observer stated that the object could possibly have been climbing when it seemed to slow down to a stop, but that he seriously doubts it.] The 360° turns were said to be very tight turns, about one-eighth of the area required for jet aircraft.”
“On 10 January 1953, between 3:45 and 4:00pm, Col. ______ and Mr. ______ of the Federal Security Agency, San Francisco, California, observed and unidentified flying object while eight miles northwest of Sonoma, California, from a knoll in the hills northwest of the Sonoma Valley. The object was sighted at a 45° angle northwest from the location of the observers at a very high altitude, so high that the object was compared to the flat head of a pin held two feet from the eye. Speed was estimated at four times the speed of a jet aircraft with accompanying sound similar to the USAF F-86 jet at high altitude. There was no change in sound tone or volume during maneuvers. Unusual maneuvers made by the object were: 1. Three 360° tight turns to the right, taking two to three seconds to complete each turn; 2. two right angle turns, first to the right, then to the left; 3. the object slowed down to almost a complete stop, then accelerated to high speed again, making this maneuver twice. The object then rose vertically and disappeared from view. Total time of obseration was estimated to be between 60 and 75 seconds. There were no radar contacts with the object. No other observations of this object are known to have been made.
The object made three 360° turns to the right taking two to three seconds to complete each turn. These turns were made at five-second intervals still holding on the same course. It continued on and made an abrupt right-angle turn to the right, followed five seconds later with an abrupt turn to the left which placed the object back on its original course. After this maneuver, the object slowed down to almost a stop and then accelerated to its previous speed, making this maneuver twice. The object rose vertically and disappeared from view. [The observer stated that the object could possibly have been climbing when it seemed to slow down to a stop, but that he seriously doubts it.] The 360° turns were said to be very tight turns, about one-eighth of the area required for jet aircraft.”
- The Hynek UFO Report, p. 109-110.