I was driving home from my brother's house when I first observed a single, very intense white light 20 degrees above the western horizon (observation point Littleton Colorado). The object was directly west, and appeared to be over the Pine Junction/Bailey area in the mountains. I kept in sight as I drove home and stood next to my car after I parked it. The entire time it was under direct observation (approximately fifteen minutes), it did not move at all.I first thought it was an aircraft or helicopter. However, the object absolutely DID NOT MOVE, not even the tiniest flucutation in position. I was using the mountains below as well as a tree to keep track of its position.It was larger than any star or planet (probably double the size of the largest star in the sky), and because it did not move even a hair during the period observed, it was not a helicopter or an aircraft. It was a circular light source of brilliant intensity that never shifted or fluctuated.The light was brilliant, almost a "pure" white light, and the intensity was so strong there is no way it was a reflected light; it came from an artificial source and never changed in intensity or in color or position.I first noted the object because I tend to look at the passing aircraft a lot, and there was moderate air traffic in the area during the sighting. What brought it to my scrutiny is that the light (object) NEVER MOVED.I went inside to find a telephone number to make a report once I determined that this object was unidentified per my forty years of intense aviation interest. I first left a voicemail message with the Noise Complaint Hotline at Buckley AFB in Denver, then called the Command Center of the 140th Wing of the Air National Guard at the same base. The female sergeant who took the call was very polite and asked very detailed questions regarding the sighting, then placed me on hold while she spoke with "her boss". She was back on the line in about two minutes and said that her boss had the object under observation, and that mine was the first call they had received about it, and I jokingly responded that "well, I'm sure that someone in the command structure is already aware of it." Knowing that US Air Force personnel had the object under observation, I retired for the evening.During the entire fifteen minute observation period, I used the mountains and the branches of a tree (there was no wind) to ensure that it did not change position. The intensity of the light never fluctuated, and the object never once moved, not even slightly.My feelings and reactions were first disbelief, trying to classify it as an approaching aircraft or a hovering helicopter, but as the object never moved, I realized that it was something that needed to be reported officially. My reaction was rather clinical and analytical, trying my best to find ANY way to identify what I was seeing.This was, in now way whatsoever, an aircraft or a helicopter, and in no way was the intense white light a reflection off a shiny surface (the object would have been far too low to catch sunlight as the sunset here is about two hours earlier than my sighting).Thank you for taking the time to read my report. I cannot classify this sighting as anything but unidentified.