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Hubble Space Telescope
Low Sky

Checking the "Low Sky" box invokes the formal definition of "Low Sky" used in Phase 1 and Phase 2 proposals. The zodiacal sky background is estimated at a value 30% greater than the minimum for the target RA and Dec specified.

This option over-rides the user specified "Sun Angle" and instead selects the appropriate heliocentric longitude for the definition of "Low Sky."

John Biretta <biretta@stsci.edu>, STScI