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MONday, jANUARY 17, 2010determining naked eye magnitudeIt is common to test sky conditions to the naked eye by noting the faintest star detectable. In the northern hemisphere, amateur astronomers often use Ursa Minor, for consistency. Consider, before viewing this image, after getting dark adapted, doing a sketch of Ursa Minor. Record all the stars in the vicinity and their general positions. Then check this against the image.
The small image is linked to a larger version. Note: the magnitudes for stars are shown in parentheses without a decimal point. For example (42) means 4.2 magnitude. I note personal magnitude limits, with and without magnification.
Images produced with SkyTools3.
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