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[ Spectroscopy ] [ Photometry ]

What is photometry?

In astronomy, photometry is the measurement of flux, or the brightness of an object, in particular bands of the electromagnetic spectrum.

Photometry and New Worlds Observer

Through the use of photometry, New Worlds would be able to roughly map oceans versus continents. This is due to the fact that albedo, or the amount an object reflects light, changes for different land/water materials. Oceans are dark, and reflect very little light, whereas deserts are bright and reflect a lot of light. The albedo for oceans is ~0.5% while the albedo for land ranges from ~10% to 30%.

With Earth-like clouds, New Worlds can roughly map
Earth’s continents and oceans at 10 pc. The Atlantic Ocean is clearly visible.

Only four to five days of mapping enable a pattern to develop indicating the planet’s rotation rate.

Earth’s reflectance curve is graphed for one full rotation (one day).


All simulations were performed by Phil Oakley.


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