- Sunrise in Walter (...Akkana)
Sunrise in Walter is like a mini-Clavius, with small craterlets inside
showing the tips of their walls while the main crater floor is still
dark. Later, light begins to play along the main crater floor.
About an hour after this sketch, 5/11/2000 0800 UT, jagged triangles
of dark and light showed along the western wall of Walter, but no
sunrise rays were in evidence. However, a long, narrow ray was
visible along the highlands north of Walter, in the vicinity of
Regiomontanus and the north end of Deslandres.
- Walter Ray (Dave Mitsky <djm28 _at_ psu.edu>)
[ ... ] I was very happy to chance upon what just
might be a new "lunar ray". I was scanning along the
terminator at 249x when I noticed a triangular ray of sunlight
streaming through a break in the western crater wall of Walter
(at approximately 2 degrees west, 33 degrees south - Rukl chart
65). The ray illuminated Walter's western floor and the lower
part of its central peak (the upper part was in direct
sunlight, I believe). At approximately 07:42 UT I spotted a
"reverse" triangular shadow being cast from an object on the
western wall onto the illuminated crater floor. I could not
stay any longer and by the time I had returned to my residence
and set up my C4.5 (about 08:30 UT) the phenomenon was over and
the crater floor was in darkness.
Location: ASH Naylor Observatory, Lewisberry, Pa.
76d53'4" west, 40d8'54" north
elevation 570 feet
Dome Temperature: 52 d F at session's end
Instrument: 17" f/15 classical Cassegrain
Ocular: 26mm Tele Vue Ploessl (249x)
Time: 07:10 UT
According to a response on sci.astro.amateur, Bob Young calculated
that at the time of the observation, the Sun's lunar colongitude
and latitude were 179.717 degrees and -1.457 degrees; its lunar azimuth was
Later, Steve Rasmussen captured
the Walter ray
with a handheld digital camera through the eyepiece of his RV-6.
- Predictions for the Walter Ray
I have generated
for the Walter Lunar Ray for the year 2000.
I have also included some new analysis and more comprehensive predictions.
L'ALPA page on the Walter ray (in Italian) for timing predictions.
- Orontius Sunrise Ray (Bill Arnett)
With some difficulty I drew my attention away from the Mare Nubium area and
scanned down the terminator to see if I could find a "sunrise ray". And
sure enough, there was one shining along the NW rim of Orontius.
After a while it started to illuminate the rim of the little
crater Orontius D. At one point it looked to me just like a connecting rod
with a big bearing and no piston just hanging there in space.
- Stoffler (<d _at_ timocharis.com> David North)
Stoffler is, at first glance, just a flat, smooth crater with some
interesting tonality. Like several other craters in the area (notably
Orontius and Walter) it has dark "rays" or spray markings on the western
side, more or less oriented in the direction of Tycho. I don't know if
there's any particular relationship, but one cannot help but be
After a while, though, I started to notice a bunch of little
craters on the unnaturally smooth surface... I'd never noticed that
before (there are three or four obvious small ones, but...) One after
another they winked into view, as my eyes "integrated" more and more.
Some would stay, others blink in and out... it was like hunting the
faint stars in a distant open cluster, slowly fighting my way to the
edge of the seeing... once again, the moon presented a new challenge in
a familiar setting.