Denver, ColoradoDecember 1956

Insufficient Data

Summary

On the evening of December 31, 1956, a resident of Denver, Colorado watched two round objects in the night sky through binoculars and a telescope. Both objects were tiny, about the size of a pea held at arm's length. One was bright white, and the other was dark. The witness, an observer with the Ground Observer Corps (a civilian volunteer network that watched the skies for military activity), first spotted the objects at a low elevation in the east, around 0640Z (roughly 11:40 p.m. local time on December 31). He thought they might be aircraft at first.

Over the next two hours and twenty-five minutes, the witness kept the objects in view as they climbed higher in the sky, moving toward the east-northeast. The objects traveled in a straight line before fading from sight. The sky was clear with no wind, providing excellent viewing conditions. The observer took photographs of the sighting and sent them for development, expecting results by January 3 or 4, 1957.

The Air Force's Aerial Phenomena Technical Operating Center (ATIC) reviewed the case but noted that without the developed photographs, their analysis was limited. The case summary suggested the objects were probably astronomical in nature, but officially the Air Force marked it as "insufficient data for evaluation" due to the lack of photographic evidence. The Air Force sent the observer a follow-up form requesting the exact course of the objects in hopes of completing their analysis, with results to be included in a monthly summary report.

The complete case file, held by the National Archives, consists of 11 pages from microfilm T1206, Roll 27.

Reported location

Denver, Colorado

Date of incident

December 1956

State / country

CO / US

Page count

11 scanned pages

USAF evaluation

unknown

Microfilm

T1206, Roll 27

Pe ys SE PROJECT 10073 RECORD CARD hl a Ee ee yy hr yw ee (ES Cr EE 6 1. DATE 2. LOCATION 12. CONCLUSIONS 0 Was Bolloon __ 31 December 1956 Denver, Colorado a Erobanty gdlieen 3. DATE-TIME GROUP 4. TYPE OF OBSERVATION eb pa (las eR Be XX Ground- Visual 0 Ground-Radar 8 Probably Avera eMT__01/0640Z Jan 57 0 Air Visual 0 Air-Intercept Radar |O Possibly Aircraft 5. PHOTOS . SOURCE 0 Was Astronomical BX es 0 Probably Astronomicol 0 No militar 0 Possibly Astronomical BN 000000 milicary 7. LENGTH OF OBSERVATION 8. NUMBER OF OBJECTS | 9. COURSE B, Othehes liaise ais R Insufficient Dota for Evaluation 0 Unknown — 2 hrs 25 min : 10. BRIEF SUMMARY OF SIGHTING 11. COMMENTS Objs round, size of pea. Color white, Photos not received. Sighting one bright obj, one dark obj in probably astro, However, case upper right, Obj was thought to be listed as insufficient data dae an a/c, Photos were taken. to lack of photos. ATIC FORM 329 (REV 26 SEP 52) / ‘ } : . LY Ee a BE B28 B04 0 HE TR a ETRE J Ea es )