Planetary observations by Bernie Kosher December 7-8, 2002 The following are some planetary observations from late Sat night into Sunday morning. Very interesting watching the satellites. The Willingboro Astronomical Society held its annual Christmas party Saturday night, and the sky seemed reasonably stable afterward, so I set up the 6" reflector for observing. Due to the snow, I set up in my garage with the scope aimed out eastward. Since the garage is a separate, unheated building, there are no troubles with heat waves. The sky was not too bad, the bit of haze settling the air to the point where the planets were blurred but occasionally fairly steady. At the altitude of Saturn, spells of about seeing (7) for a few seconds here and there allowed use of 180X for those few seconds and an occasional 270X. But those spells were far apart. Anyhow, about 11:30PM local I started on Saturn, as Jupiter still had not cleared the house. The south equatorial belt was easy, as were Cassini's division, and three faint satellites in an arc, and Titan well away from the planet. The most striking sight was the ball of the planet against the Cassini division. Apparently, the division is about tangent to the ball of the planet at the south pole. This gave Saturn's south polar areas a really odd look. The southernmost polar area appeared very dark and broken due to the normal limb darkening and the Cassini's division running about parallel to it. There looked like four distinct blobs of darkening strung along a dark shallow curve. I suspected an intensity minimum at about 2/3 outward of the width of A ring, but the seeing was not stable enough to swear to it. Perhaps wishful thinking. Also, a distinctly darker circular area on the southern leading edge of the A ring would occasionally flicker into view. It appeared perhaps 3 seconds of arc in size, and was only visible when the seeing was stable. These local darkenings have been reported for years, and may be a real bunching effect or may be illusory. The C or 'Crepe' ring was easy, appearing as a gauzy glow in the ansae and looked to be about 2/5 the width of the ring/planet separation. Against the planet the ring appeared as a faint shading of less apparent width. I suppose this is due to irradiation from the brighter background. Jupiter cleared the house about midnight, and two of the moons appeared to be very close together, on the following side of the planet. As I watched they moved closer together. At about 12:30 the images blended into an elongated figure eight. Whether a real occultation or just a close miss occurred was beyond the seeing. At the time the planet was still low in the sky and also was affected by the heat from the house's chimney. The equatorial belts were of course easy, with an occasional shot of the north belt seeming to split into two for a bit of its length. I later used TheSky program and the Observers Handbook to find the moons were III Ganymede coming out from occultation and I Io approaching transit. Io's shadow moved onto the planet at 12:40 local time. Satellite II Europa was behind the planet and IV Callisto was well off to the east. A fascinating sight, and, if your timing is right, one which I would recommend to anyone. No, it wasn't all that cold. BK
Saturn Earth's Moon by Bernie Kosher September 9, 2001 Too nice out last night to be inside, even though it was hazy/cloudy, so spent some solar system time... Observations - Sunday morning 1AM Saturn has just cleared the rooftops. It still looks like Saturn. Passing clouds and some pretty bad turbulence limit power to under 150X. The rings are about as open as they can get, and actually appear to be clear of the limb of the planet, but this may be illusory, as the planet is low and the red and blue upper and lower bands due to atmospheric dispersion blur the normally sharp edge. Also the darkening of the polar areas prevent being sure exactly where the ball of the planet ends. Not really sure if I'm seeing a shadow of the rings on the planet, although there should be at least a narrow one. Only one broad band is visible, with little detail. Even Cassini's division blurs out occassionally. Titan is easy, about 5 widths preceding the planet, but other moons are just momentary flickers. Earth's moon is much higher, but still blurred. No craters visible on the floor of Plato, but the rilles at the north end of the Appenines are easy at 120X. Occassionally, they can be traced into the mountains, apparently undeviated. The rille along Rima Fresnel III, and along the Fresnel Promontory are not far from the advancing terminator, the contrast of the shadows and bright rim making this easy to see. East of Plato in the Mare Frigoris, very near the North Pole, are several large and easy domes, well seen with the setting sun illuiminating one side. What's this?... one has a tiny crater centered on it's summit. Further south, about at the center of the gibbous disk, is the winding rille through the crater Hyginus, branching into the highlands near Agrippa, and the Ariadeus rille disappearing into the darkness. The Hyginus rille is not evenly wide along its length, with noticable rounded sections. Perhaps, slumped walls? In the crater pocked south are sights too numerous to mention. The floor of giant Clavius is riddled with craters small and large, along with bumps and valleys and an odd moutnain or two. Striking at sunset. I really wish I spent more time studying our nearest astro neighbor. There really are a lot things to see. BK
Details in Saturn's Rings Jupiter's South Equatorial Belt by Bernie Kosher November 23, 2000 For the past couple of weeks, Saturn has been at opposition and shown some points of interest I've never noticed before. As I scan along the rings from the ansa to the ball of the planet, the inner edge of Ring B has shown some noticeable indentations, where the rings are just not as dark as the surrounding areas. This seems to be a contrast effect, and not a real event, as the area under observation remains stationary and does not follow the rotation of the rings. Otherwise, I would think it an unusual appearance caused by darker areas of the ring under high solar illumination and wide open angle of view. This is certainly not a turbulence effect or a distortion caused by rising heat waves in the scope, as the impression is visible only during those moments when the seeing steadies and the edge of the planet gets that hard and sharp appearance. Scanning in further, I was seeing Terby's spot on the leading edge (western) up until the first week of November, after which time the spots were visible on both sides. The spots are named for an astronomer of the late 19th century who was the first to call attention to them. I'm not sure I have the spelling correct. What they are is an apparent brightening where the rings touch the planet at the obscured side. But the strangest thing of the last week or two has been a small dark dot next to Terby's spot, brought to my attention by Alan Daroff, a planetary observer of considerable skill and member of the Willingboro A.S. This spot has been visible on both sides of the ring at the juncture of the rings and planet. These observations may be a contrast effect, or may be hallucinations, as I have never seen reference to them in print. The dark spots may be a contrast effect caused by the Cassini's division and the relatively dark polar area of Saturn's disk. These dark dots appear to be superimposed on the B ring, not where the Cassini division would be. However, since I have not seen anything in the literature about this effect, it could well be imaginary. In use were my own 4.5" refractor at powers ranging from 140X to 250X and a 5" f/15 refractor at the same and higher ranges. The spots actually made the planet look like it had, of all things, tiny Mickey Mouse ears. Jupiter continues to show a remarkable split in the SEB on the side of the planet opposite the Red Spot. The SEB itself has regained much of the density it lost last year. If I recall correctly, I read of this happening in the early sixties, after which the Red Spot darkened considerably. I started observing with a home-made 6" reflector in the mid sixties and remember the Red Spot as the first thing one saw when looking at Jupiter, as it was then as dark or darker than the bands. This time of year brings really poor seeing with high altitude winds, cold fronts and the Jet Stream wreaking havoc with the atmosphere. Rising heat waves from houses and such compound the problem, as does trying to stay warm and not have the scope blow around. It requires staying at the eyepiece for a long time to see any of these things, which will limit the number of observers trying to verify them. I sincerely hope some of our gang braves the nastiness and gets outside. It will prove well worth it, even if you can only say, "That Achmet is full of aberrations." BK
