WAXING CRESCENT MOON

2015 February 21, 7:38 p.m. EST (Feb. 22, 00:38 UT)
Rosemary Hill Observatory • Bronson • Florida

Brief Object Notes: Crescent Moons reveal only small sections of the lunar landscape but deep shadows reveal a wealth of detail. However, thin Crescent Moons are also near the Sun on the sky so observations are time limited with the Moon moderately low in the sky.

Photograph Below: Taken with a 5-in., f/5.2 refractor under very hazy skies and poor seeing. A 4x amplifier increased the telescope's focal length from 660 mm to an effective focal length of 2,640 mm. Not an outstanding photo due to poor skies but several prominent and well-known craters are visible, at least to experienced lunar observers! This includes the Mare Crisium basin. Still guests who saw this view "oohed and aahed" when seeing this crescent at the AAC star party! Here the Moon is only 3.0 days old (13% illuminated) at an altitude of 25 degrees above the western horizon with an elongation from the Sun of about 43 degrees.

Originally the goal was to photograph the planet Uranus as it emerged from behind the bright limb of the Moon at 6:51 p.m. EST after having been previously occulted.

However, haze and clouds not only diffused the lunar image but also caused the surrounding sky to be polluted with scattered moonlight. Therefore, viewing Uranus appeared impossible. Even when this photo was taken 47 minutes later, little hope remained that Uranus could be seen though Uranus would now have been about 23 arc min from the bright lunar limb.

Even so, see the page titled, Crescent Moon and Uranus for more details and a remarkable picture!

PUT CURSOR OVER IMAGE BELOW FOR LABELED IMAGE — ALSO CLICK IMAGE TO ENLARGE

Photo Details 2015 Feb. 21, 7:38 p.m. EST TeleVue 127 mm, f/5.2 APO Refractor, Foc. Len. 660 mm w/Televue 4x Powermate (Effec. Foc. Len. 2,640 mm) Camera: Canon DSLR EOS 5D II, Exposure 1/20 sec, f/21 (ISO 2500)

OBSERVATIONAL CHALLENGES People often ask if the flags planted by Apollo astronauts on the lunar surface are visible from earth-bound telescopes. Of course not. But how small an object can you see with your telescope? FYI: From Earth, one arc second corresponds to about one mile on Moon (more precisely, 0.9 mile). Note that astronomical seeing disks of less than one arc sec are very rare. Observe the Moon with your scope & find features at the limit of resolution Use software, maps, the Internet, etc. to find its linear diameter Use Charles Wood's Lunar 100 Map to find 100 of the Moon's most interesting features Qualify for the Astronomical League's Lunar Program Certificate. Use these dedicated Lunar Maps I produced to help complete this rewarding program QUESTION: Craters are usually named for deceased scientists and explorers. Among fans of Star Trek, Jean-Luc Picard (played by Patrick Stewart) is the well-known captain of the Star Ship Enterprise in the series, Star Trek: The Next Generation. No lunar crater, of course, is named for this character but a small, 14-mile wide (23 km) crater bears the name Picard named for Jean-Félix Picard (1620-1682), a French astronomer. This isolated crater, in a large basin, is easily visible, even in small telescopes. It is most easily seen three days after New Moon or two days after Full Moon when this feature is near the lunar terminator. Therefore, Picard is easily visible in this three-day-old moon photo especially in the enlarged image. Can you find Picard? ("Trekkies" need to know!) ANSWER HERE

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Images © 2004–2015 H.L. Cohen
Email Cohen followed by @astro.ufl.edu
Last updated 2015 May 18