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The California nebula is a large and fairly bright emission nebula in the constellation Perseus. This image is the result of about 12 hours total exposure through Hydrogen-alpha, Oxygen-III, and Sulphur-II filters, rendered using the Hubble palette. The Hubble colors reveal a remarkable amount of detail in the chemical composition of the nebula. There are areas of hydrogen only (the green parts), sulphur only (blue), areas where all three are strong (white), and various other mixtures.