Thursday, February 07, 2008

Crescent moon alert

Moon Watch at sunset tonight.

Tonight at sunset 5:20PM EST, look for the new crescent moon a little greater than the width of fist off the southwestern horizon. A very young moon, the 18h35m moon rides atop a steep ecliptic which provides a greater elongation from the Sun than an inclined ecliptic, dramatically increasing chances of success. As the Sun sets below the horizon, the moon is setting also but remains above the horizon longer. The moon is just shy of 7 degrees above the horizon at sunset. Further, the sky darkens and contrast increases to help sight the slender, wispy lunar limb. With its angle of attack the limb will appear like a smile, perhaps with some lumpiness. Locally, the moon sets at 6:06PM EST.

Here in NYC, I recommend a pair of binoculars at the least to spot it and then try naked eye after it is located. Forecast calls for clouds at 5:20PM EST but they've been wrong before. Go ahead and try.

The Sun sets at azimuth 250┬░at 5:20PM EST. The crescent moon hangs above that point in an "11:30" position, as noted in the illustration above. If sky conditions are agreeable, I anticipate a sighting about 14 ~ 18 minutes after sunset.

Regardless, try for the crescent tonight and then submit your report to the organization linked above.

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