The Cichus A Lunar Ray Reports

Observer: Tony Donnangelo
Date/time of observation: 2003/12/03 03:05 U.T.
Site location: Hummelstown RD 3, PA, USA (40.26° N., 76.75° W.)
Site elevation: 479 feet (146 meters)
Site classification: Suburban
Instrument: Takahashi FS-102 f/8
Magnification: 273x
Object: Cichus A

I started my observing session at 01:00 U.T. The temperature was 29° with a wind-chill factor of 19°. It was clear and fairly transparent early in the evening. A few small cumulous clouds were moving through the area. By 04:45 U.T., sky conditions deteriorated. The moon was getting low in the west (setting time was 07:05 U.T.), and a fast moving, high, thin cloud layer caused a hazy appearance around the moon.

At 03:05 U.T., I observed the beginning of the ray two minutes before the predicted time. It occurred in a triangular area just south of crater Cichus A, with the apex of the triangle pointing north. It originated from a crevice in the eastern wall near the southern end of the formation.

The narrow ray extended west and slightly north to the base of the western ridge. The summits on both sides of the formation and the interior western wall were illuminated. The floor was completely shadowed, except for the ray. The illuminated summits and the ray appeared to form the letter “A”. A narrow shadow bisected the ray near the western edge.


Larry B Smith reported seeing the sunrise ray on 2/24/99 at 20:30 eastern time at coordinates 20.5W, 36.5S on Rukl chart #63. He estimated the length of the ray to be about 30km long.

06/09/2003  3-5:30 UT
Wichita Falls,Texas 33.824,-98.544
Mostly cloudy skies, Moon 66% waxing gibbous, seeing good.
8"f/6 at x260
For over two hours I sat mostly waiting for the moon to show through the cummulus clouds rolling around overhead. On occasion I could pick out the close satellite and from time to time the view was remarkable.
The search for Cichus A sunrise ray yielded a big "I think I see it". This area was easy enough to find from the excellent description by Larry B. Smith. His discovery and timing report are listed at Rob Robinson's Lunar Observatory. At 3:40 UT, a few quick glances through the 4.7mm Meade UWA eyepiece were enough to convince me that there was indeed a stubby shaft of light reaching westward towards the receding terminator. After awhile it was more washed out with the rest of the floor becoming illuminated. The clouds kept the suspense up, only allowing me a furitive glance every few minutes.
A search for the sunrise ray in Kies was unsuccessful due to the thickening cloud cover. By 5:30 UT it was completely overcast. The last view I had showed the floor of the crater was becoming illuminated and the "bump" east of the western wall was visible. A look south to Palus Epidemiarum region did not show the multiple rays discovered by Akkana Peck somewhile back. I remember seeing these just prior to the Kies discovery. Perhaps the tilt of the moon was not the same to repeat these coincidences, or the predicted times are a little off as yet to be confirmed and adjusted.
-David Ryle