by Jay Reynolds Freeman
On Friday, 8 September, 2000, I helped at Lick Observatory by providing a telescope to help show celestial objects to guests at a summer lecture program. Lick makes one or two of its own telescopes available on such occasions -- the 36-inch refractor was pointed at the 9-day old Moon, and the 40-inch reflector at the Moon and later at the Saturn Nebula -- but with nearly 200 attendees, lines at the big instruments do get long.
I brought my own big instrument, Harvey the Celestron 14. The night was unusual, in that I generally use the C-14 as a deep-sky telescope, so the only Moon it usually sees is a thin crescent sinking rapidly toward the western horizon, prior to the start of an evening of faint fuzzies. I am not sure I have ever had Harvey set up with so much Moon in the sky. Seeing was pretty good, and one of the highlights of the evening was walking an interesting lunar terminator with more telescopic power than I had ever brought to bear on it.
I started setting up before sunset, and began to observe while the sky was still blue and the Moon was the only celestial object in sight. My compass-and-latitude-angle alignment was off -- even with lunar rate in the Losmandy G11, I kept having to recenter the view in the 261x eyepiece (Vixen Lanthanum 15 mm), but the seeing was quite good. I did a better polar alignment later, when Polaris became visible.
At the start of the evening, the terminator was just crossing crater Brayley, at selenographic longitude 37 east, creating near-optimum conditions for observing the delicate Brayley rille. This thin dark line is as elusive on charts as on the Moon itself -- it does not appear in some of the older, small-format editions of Rukl's lunar atlas. I had seen a portion of it before, with my Meade 127ED (one of the good ones), and I was pleased to find that Harvey showed more. My glimpses were intermittent, and all lay within 50 Km north of Brayley.
Further south, I could see portions of Rima Milichius, the northern half of Rima Herigonius, essentially all of the Rimae Hippalus that are shown on the large-format Rukl charts, and all of Rima Hesiodus. The latter is not particularly difficult as rilles go, but its (selenographic) easternmost portion was some 20 degrees from the terminator, and the rille's orientation is nearer east/west than north/south, which means that its walls were not favorably placed to cast shadows. So I was pleased to see it all.
There is always far more detail on the Moon than I can see or record, but among the other features I noted was an excellent example of a lunar dome, Milichius pi, at about 10 N, 31 E, well illuminated a few degrees away from the terminator. I could also see the slightly off-center craterlet on top of it.
Local lunar enthusiast Dave North was also at Lick that night. At one point he watched me quietly for a while as I scanned the terminator at the eyepiece, then spoke up softly, "I won't tell." I chuckled -- he was referring to my breaking tradition with my more usual lunar observations, which consist of a brief glance through the eyepiece and the remark, "Yup, still there," before going on to something else. I was indeed breaking tradition, but that was because I had forgotten how much more a large telescope will show.
As the public left the lectures and wandered out to look through our equipment, I was glad I had brought Harvey. The C-14 was the largest telescope in the Lick parking lot, and aperture helps a lot in showing deep-sky objects in bright sky. M57 and M15 were easy to see and interesting to look at at 261x, nine-day Moon notwithstanding. Many people wanted to look at a galaxy, and though only the nuclear lens of M31 was prominent, it was enough to satisfy them. I gave several people a view of epsilon Boo, well resolved and showing a clear white/blue color contrast, or of Polaris, whose companion was a little more difficult for folks who did not know what to look for without coaching.
A young lady asked rather plaintively if there were any planets visible. No problem for big iron. Fortunately, Uranus and Neptune were both placed relatively close to stars in Capricorn that are normally naked-eye. The Moon was too close to that area for me to see much of the constellation beyond its brightest stars, but they were enough to get me oriented, and the normally naked-eye stars showed well in the finder, so I located the two outer gas giants quickly. Neither of these worlds is much to look at in any terrestrial telescope, but they were clearly non-stellar, and colored, in the C-14. Uranus's green usually suggests to me a rather dull piece of jade, whereas Neptune's blue is almost celestial in hue, and very pretty. The lack of detail on their discs was balanced by the fact that almost none of the public had seen them before, so the yen for planets was satisfactorily satisfied.
After the guests had gone home, we tried some more difficult objects, still at 261x. I could see NGC 7331 and the four NGC galaxies that lie to its east, namely 7335, 7336, 7337, and 7340, but only the brightest member of Stephen's Quintet, NGC 7320.
We also got a chance to look through the 36-inch at a couple of objects. I had not gotten in to look at the Moon through it, though I had seen the same area -- Clavius -- with it, a few months before under better lighting conditions. The other two objects, shown to just we volunteers, I had not seen with so much aperture.
The first was M15. The view at 496x (35 mm Panoptic) was splendid, showing stars well resolved all the way across the field of the eyepiece and all the way across even the densely-packed core of the globular. 496x with this instrument is a rather low magnification, giving a 1.84 mm exit pupil, so the sky background was still brightened notably by the Moon. Even so, I have never before had such a wonderful view of this object.
The second object, at the same magnification, was Neptune. As I said, it's not much to look at in any terrestrial telescope, and the view through 36 inches of aperture was a lot like the one through 14. Yet there was Triton, hanging beside the planet in a moonlit sky, as a nice finale to the evening. It doesn't take that much aperture to see it -- I have done so in a 12-inch Meade LX200 -- but with so much Moon, I had not been able to detect it in Harvey.
Helping out at Lick is always as much a pleasure as it is an honor; I had a fine night.