Seen: ICOP member Mr. Jim Stamm (Tucson, Arizona) said:
Location = Tucson, Arizona (USA)
Longitude = 110.9645 W
Latitude = 32.4204 N
Elevation = 842 meters
Time Zone = -7.0 hours
Surface conditions at time of first/last sighting at
Tucson International Airport (805 m):
Temperature = 84 degrees F
Relative Humidity = 13 percent
Sea Level Pressure = 1007 mb
Scattered clouds, but not a problem.
Topocentric and local time values from “Accurate Times”:
Sunset (at sea level) = 19:27
Moonset (at sea level) = 20:13
Time from new moon at 19:47 = 15 hr. 36 min.
Moon lag time = 46 min.
Relative Altitude = 8.27 degrees
Elongation from sun = 8.28 degrees
Crescent width = 10 arc seconds
Illumination = 0.52 percent
Crescent first observed through 8” SC telescope:
Time = 19:29
Altitude = 5.9 degrees
Final observation with telescope:
Time = 19:45
Altitude = 3.0 degrees
This was a difficult observation. The crescent never got as distinct as my record time observation. Initial view (19:29) was about 10 degrees in arc length. 15° at 19:31; Hints of extensions at 19:34; 40°-50° at 19.36; I could not see the entire arc at once. I had to scan with my eye. However, the entire arc was illuminated, some sections brighter than others. 60° at 19:40; 70° at 19:42; 80° at 19:43; 90° at last observation (19:45). The brightest part of the illuminated arc was not visible until about halfway into the observation. I did not realize the significance of this phenomenon at the time, and did not time its appearance. I do not know if the "bright" section of the arc (a few degrees at most) was due to albedo, or an illusion due to surface features - i.e. a wider part of the arc."