Observing notes - Ealing 4-26-2007 Lunar visual 9:30pm - 12:30am 4/26-4/27. Temp. 48 deg. Sky brightness 16.5B (v2.7). Moon az 183, alt 58. Terminator approx. W 28 deg. Lunar age 9.6 days. Seeing: 4/5 poor. Wind at 9pm 5mph dropping to zero after 11pm. Basic night of lunar visual observing with objective of testing lenses and maximum useable magnification against lunar targets. With the Ealing's 5080mm focal length, a 9mm lens yielded about 560 power, a TFOV of about 330 arcsecs, and an linear lunar FOV of about 650 kilometers. At 560x, diffraction limited effects began. This was consistent with a magnification per inch of aperture of 35.8 - a power useful for resolving specific lunar and planetary detail. A 6mm lens at 840x was also tried. The image was useable for investigating small details but showed severe diffraction limited effects. At 53.8 mags per inch, this is a power appropriate for double star work. I began the evening at C. Copernicus. The terminator was to the west, crossing to the west of C. Lansberg and C. Hortensius. Rukl Charts 31 and 32. This put Copernicus in low angle illumination of about 8 degrees. At 158x, the Copernicus region and the surrounding dark pyroclastic deposits of west and central Sinus Aestuum and Rime Bode had good contrast. http://members.csolutions.net/fisherka/astronote/plan/dhccat/DarkHaloCraters... At 560x, the dark halo crater Copernicus H (Rukl 31) could be distinguished as a DHC. Although seeing was poor, paradoxically, difficult lunar object Rima Gay-Lussac was visible with good detail to the north of Copernicus. (Rukl 31). My principal interest in this region was to watch sunrise over the eastern end of the Hortensius dome field. (See Rukl 31) LPOD 3-26-2004 - view of the Hortensius dome field http://www.lpod.org/archive/archive/2004/03/LPOD-2004-03-26.htm The classic domes north of Hortensius - Hortensius 2, 3, 4, 5 6 and 8 shown in the 3-2-2004 LPOD were viewed for about an hour coming out of the lunar terminator at illumination angles of 0 to 2 degrees. After a brief trip north to view a low-angle 50-kilometer shadow cast off of Promontorium Laplace on the east end of Sinus Iridum (Rukl 10), I then wandered south past Copernicus and prominent crater Bulliadus (Rukl 53). Lunar dome pi Kies was especially well lit, showing a good illumination gradient on both the sunward and terminator sides. (Rukl 53). LPOD 3/23/2007 - C. Kies and dome pi Kies. http://www.lpod.org/?m=20070323 Kies is about 100 kilometers north of one of the longest rille on the Moon - Rima Hesiodus. In low angle light at 560x, I was able to trace Rima Hesiodus from its eastern beginning in the wall of C. Hesiodus (Rukl 54) for about 250 kilometers before it disappeared into the terminator north of C. Capuanus. (Rukl 63). LPOD 2/20/2005 - R. Hesiodus http://www.lpod.org/archive/LPOD-2005-02-20.htm Note how the rille fractures a mountain range - Rupes Mercator - (Rukl 53) in the process. The east graben of fractured-floor C. Pitatus (Rukl 54) under low-illumination showed a distinct tilt relative to the other subsections of the crater floor. LPOD 3-13-2007 - Pitatus and R. Hesiodus http://www.lpod.org/?m=20070313 The lunar part of the evening ended with a dramatic sunrise over C. Capuanus that took up a good 15 minutes of viewing. A peak on the east wall of Capuanus cast a sharp triangular shadow across the crater floor, ending in a point on the west wall of the crater. LPOD 2/11/2005 - Capuanus http://www.lpod.org/archive/LPOD-2005-02-11.htm After a snack and some coffee, it was time to switch to a quick colorful double star before closing the Ealing roof cover for the night. Belmont Society recommended bright colorful double eps Boo has a 3 arc separation with a white-yellow primary and a dimmer topaz secondary. The 6mm lens at 860x nicely split this colorful double, but the size of the seeing disk of the primary put atmospheric turbulence at about 2 arcsec. eps Boo is ST513 in the Ealing Skywizard DSC - useful info for the next couple of Moon washed-out sky. Clear skies - Kurt P.S. An owl and several bats were heard throughout the night. The dog at the house to the northwest incessantly barked from 9:30pm to 1am - similar to its behavior in past years. That dog really has the potential to create some conflict between the home's owner and the observatory. _______________________________________________ Sent via CSolutions - http://www.csolutions.net