Hitchhiker's Guide to Rukl Chart 65

Sunrise in Walter (...Akkana) [Sunrise in Walter]
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 
Seeing: good 
Transparency: good 
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 268.543 degrees.

Later, Steve Rasmussen captured the Walter ray with a handheld digital camera through the eyepiece of his RV-6.

Predictions for the Walter Ray (Rob Robinson)
I have generated predictions for the Walter Lunar Ray for the year 2000. I have also included some new analysis and more comprehensive predictions.

See also the 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 suspicious.

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.

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This page last modified: Dec 06, 2020
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