UFO in Oregon with movement and color changes

Summary

An observer in Oregon reported a UFO with a conical shape moving from east to southeast. The object, seen for 90 minutes, changed between blue, red, and bright white. Initially at about 10 degrees elevation, it ended at 30 degrees. Although there were other bright stars, Sirius was a key reference. The witness, a farmer with a commercial pilot license, described the phenomenon accurately. The Air Force requested additional information to evaluate the case.