Observer: Tony Donnangelo Date/time of observation: 2003/01/12, 00:15 U.T. Site location: Hummelstown RD 3, PA, USA (40.26° N., 76.75° W.) Instrument: Takahashi FS-102 Magnification: 91x (9mm NaglerT6), 158x (Pentax 5.2mm XL), 234x (3.5mm Vixen SW)
This was the first time I observed this ray. I began to see the ray develop approximately one hour before its predicted time. I first observed an illuminated area on the inner part of the western wall. The floor of the crater was completely dark. As the sun rose, the ray started at the western wall and began to stretch across the full length of the floor. It was narrow and slightly cone shaped. It began to widen slightly and quickly. After a short time, the widening subsided for the rest of my observation. After approximately 2 1/2 hours, the western half of the floor was illuminated, but the ray was still evident in the still darkened eastern half. It vaguely appeared to be seen slightly in the illuminated western section of the floor, also. Dave Mitsky joined me during this observation session. At 04:00 U.T., we dragged our frozen bodies into my house and called it quits for the night.
Craters Pitatus and the Hesiodus sunrise ray on October 7 05:00 UT (10:00 PM PDT). This is a 9 day old waxing moon. Telescope: 10 inch f/7.3 reflector using a 6m Vixen Lanthanum eyepiece for 309x. Pitatus is a flooded walled plain. Rimae Pitatus, the clefts within Pitatus are visible in the sketch. The ray breaks through a crumbled wall between Pitatus and the small crater Hesiodus. To me the ray appeared to curve a bit. (Rukl 54) - Jane Houston Jones |
From:Gary Pikegary - pike@bright.net
Date: Fri, 23 Aug 1996 01:30:01 GMT In the July issue of Sky & Telescope is an article on a phenomena called the Hesiodus Ray. Philip Koch of Las Vegas, Nevada noticed a ray shining through a break in the wall of Pitatus as the terminator approached these two craters. The walls of Pitatus and Hesiodus touch each other. The light of the rising Sun shines through a lowspot and bisects Hesiodus. An article by Alan MacRobert highlights this feature and provided dates and times from June to December to search for the Hesiodus Ray. I didn't read the article in time to search in June. In July, the sky was cloudy. The time to search in August was listed at 0 hr UT for the 23rd, 8:00 EDT. I carried my ten inch F4.5 Dobsonian out at 7:30 and began searching. Pitatus was a challenge to see because of the bright sky as it was still an hour away from sunset. I kept searching and as the evening went on, I was able to see the shape of Hesiodus. The top of the crater's rim was in the sunlight. There are a couple of bulges in the rim. These bulges are opposite the break in the crater's walls. Using the shadows of central peaks of nearby craters, I determined the direction of sunlight. One of the bulges in the wall appeared to extend towards the break in the opposite wall. If I had drawn the image at 0:15 UT on August 23rd, I would have drawn a feature that extended only ten percent of the way towards the break. A couple of times, I thought I saw a line extend all the way to the break, but I felt it was just my mind connecting two points. As the sun worked its way to setting, the sky darkened and the Moon's features were easier to see. At 0:32 UT, August 23rd, I saw it. A definite ray connecting the break in the wall and the far side of Hesiodus. I called a fellow astronomer who I knew would be out looking for it. Ron Netzley was using his copyscope and had not yet spied it. As we were talking, I heard him shout, "There it is!" He saw it at 60x. I could see it at 128x and 230x. At 44x, there was something visible in the crater, but I couldn't really make out the ray. So two amateurs from western Ohio were able to find this feature. As I type this, it is 1:30 UT August 23rd. The ray is still visible, some sixty minutes later. From:Tom Polakis - polakis@indirect.com
Date: Thu, 22 Aug 1996 21:35:37 An article on p. 74 of the July issue of "Sky & Telescope" describes the sunrise ray in the lunar crater Hesiodus. Philip Koch of Las Vegas, Nevada noticed the phenomenon, which is the result of a narrow beam of sunlight emerging through a break in the crater wall, illuminating its floor. The length of time around sunrise on this crater that this feature can be seen is not known. Alan MacRobert provided a summary of prime times for the rest of the months in 1996. Last month, the time of sunrise just west of Hesiodus was 13h UT on July 24. The best I could do in Arizona was look at around 5h UT, as the Moon was getting low in the western sky. The ray was not visible, nor was the rim of Hesiodus. It was just too early to see it. The next favorable appearance would occur on August 23 at 0h UT, or just before sunset in Arizona. I set up my 8-inch scope as a desert dust storm was dying at about 2h UT. Even though the sun was just setting, and the seeing was about 5 arcseconds, there was the ray, easily visible at 150x! About all I could discern in the shimmering image was something that looked quite a bit like Koch's sketch in S&T. The ray did seem a bit more centered inside the crater, splitting the crater evenly. Koch draws it north of the center. Perhaps this is due to the difference is selenographic latitude (see the article). Two hours later, at 4h UT, the eastern half of the floor of Hesiodus was illuminated, which meant the ray was no more. All that was left of it were two symmetrical shadows around the origin of the ray along the western rim of the crater wall. The next good opportunity to see the Hesiodus ray for North American observers occurs on October 21, at 3h UT. In this case, we have a chance to see almost exactly what Koch saw. From:Jeffrey R. Hapeman - jhapeman@students.wisc.edu
Date: Fri, 23 Aug 1996 00:47:19 I also caught the Hesiodus Ray, although by the time the clouds cleared enough for me to observe, it was more of a 'Hesiodus Cone' than a thin ray. I'm located in central wisconsin, and the clouds did not clear here until about 4:30UT, August 23. One nice thing was to look just a little distance north from Hesiodus into Mare Nubium, wher Rupes Recta, the 'Straight Wall' was clearly visible. Two lunar treats in one night! -- From:Jay Reynolds Freeman - freeman@netcom.com
Date: Fri, 23 Aug 1996 08:12:17 GMT I am glad someone had success. I was observing from Palo Alto, California, at almost exactly the times reported (from about 0015 through 0045 UT, 23 August 1996), but because of full daylight, slight haze and poor seeing, I could not see much of any detail along the terminator. I was using a 60 mm refractor at 41x, 70x and 117x. With this instrument I had seen the ray on June 24, rather late in its apparition (clouds had blocked it earlier). I was hoping for a better view, but I guess I will have to try October. From:Jay Reynolds Freeman - freeman@netcom.com
Date: Sun, 20 Oct 1996 22:49:43 -0700 I observed the Hesiodus ray on the evening of 20 October, 1996, from my yard in Palo Alto, California, using a 102 mm f/9.8 Vixen refractor (conventional doublet) at 250x. Seein was such that the Airy disc of a fifth or sixth magnitude star showed continuously, but that the first diffraction ring rarely showed at all. At 0330 UT 21 October, 1996, the ray extended all the way across the floor of Hesiodus, which was still in shadow, although the western part of it was beginning to brighten, even as I watched. The ray was interrupted about a third of the way from the origin (at the Pitatus end) to the western wall of Hesiodus. At 0430, when I looked again, the shadow of the eastern wall had withdrawn about a third of the way across the crater floor, but the ray was still well-defined in the shadowed area, and still intermittant at approximately the same place on the crater floor. From:Jeffrey R.Hapeman
Date: Mon, 21 Oct 1996 07:45:21 -0500 I observed the Hesiodus ray from approximately 0250 UT to 0315 UT from the front yard of my residence in Madison WI. At that point clouds interrupted the viewing. The seeing was good, but I was pushing the limits of my 70mm f/6.8 Pronto at 200x. The ray did not become visible until about 0255 UT form my position, and slowly grew across toward the western wall of Hesiodus. By 0314 UT, just before the clouds rolled in, the ray could be seen extending nearly all the way across the floor of Hesiodus, and the eastern wall and floor of the crater were beginning to become illuminated. Like Jay, I also observed a small break in the ray about 1/3-1/4 the distance of the western wall of Hesiodus (near Pitatus). Upon returning indoors, I checked the July issue of Sky and Telescope, and found that what I saw was nearly identical to the sketch made by the ray's discovere, Mr. Koch. Upon checking the chart, I was this was not surprising as the moon was in nearly the same relative position to the sun and the earth as when he observed the ray first in 1988. I would say the appearance of the ray was much different than my last observation in August, when the ray appeared much more cone-like. This time the ray was thin and dagger-like, slicing across the dark floor of Hesiodus. Very impressive! And of course, while I was there, I took the time to take a quick glance at Rupes Recta (like last time), a favorite lunar site!From:
freeman@netcom.com (Jay Reynolds Freeman)
Date: Thu, 19 Dec 1996 07:46:00 GMT Despite a cold and the prospect of having to get up early, I stayed up late enough on December 18-19 to watch the start of the Hesiodus ray apparition from my yard in Palo Alto, California. Seeing was pretty good -- diffraction rings around Polaris were continuously visible, but continuously in motion, in my "Baby Brandon" 63 mm f/5.6 refractor at 141x. I was using my Vixen Lanthanum 2.5 mm eyepiece for the first time with this instrument; it worked very well, and gave sharp images all the way across the field. The Brandon was doing a fine job as a "quick look" telescope. At about 0655 UT 19 December (1055 PST on the 18th), Hesiodus lay with its bright-rimmed bowl almost completely filled with darkness, but the gap in its wall into Pitatus was clearly visible, as was the bright spot on the opposite wall of Hesiodus where sunlight was already streaming across the crater. Over the next 25 minutes the ray developed, starting at the west wall and growing back toward the gap at the east, narrow and fine, wider at the west than the east. By the time I went back inside at 0720 UT, it was at least 75 percent of the way across the crater, and a little south of center. The ray was not sharply defined; larger apertures may have seen more of it than I did, or sooner, or both.