September 10, 2015

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Eight is Enough

Originally published September 9, 2004


Image Credit: Peter Lawrence

Eight is Enough

The Moon is the most incredible object in the night sky - at least visually. Hour by hour and night by night it moves across the sky, changing its illuminated shape. This progression is dramatically illustrated in a mosaic from eight consecutive nights of imaging by Peter Lawrence. This shows how short the good observing time is for even a large region - for example, the Crisium area is near the sunset terminator for just three nights, and then its gone for two weeks. This eight night mosaic also demonstrates a 10 degree change in N-S librations (the "yes" nodding of the Moon): On August 29th, when the N-S libration is +6 degrees, Plato and Mare Frigoris are far from the northern limb, but by September 6th, with a libration of -4 degrees, the features are squished up near the limb. This sequence of images also demonstrates changes in the Moon's diameter. On August 29 the Moon was 373,257 km from Earth, and eight days later it's distance had increased to 407,453 km. Look at the images - the August 29th image is bigger than the September 6th one! There is only one mystery: how could anyone in England get eight consecutive clear nights?

Chuck Wood

Technical Details:
4" f/9 refractor and an Olympus C-2100uz digital camera coupled to the refractor afocally.  A 20mm Kellner eyepiece was used in the camera adapter and the Olympus was set to it's maximum optical zoom (10x).

Related Links:
Pete's Longer Moon Sequence

Yesterday's LPOD: Where in the Moon is Nielsen?

Tomorrow's LPOD: Viscous Volcanics?


Author & Editor:
Charles A. Wood


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