TIP /AIRMASS

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TIP /AIRMASS

        /AIRMASS airmassStart [TO] airmassEnd [BY] airmassStep

        range of airmass for TIP.

        Real      :: airmassStart      !
        Real      :: airmassEnd        !
        Real      :: airmassStep       !

        NOTE 1: elevation = ASIN(1/airmass)

        NOTE 2: for slew-tips, TIP /SLEW:
                airmassStep has no effect
                airmassStart > airmassEnd is allowed; this implies:
                elevation (at start) < elevation (at end), i.e.,
                TIP from low to high elevation.

                (for "traditional" TIP with /SLEW no, airmassStart < airmassEnd,
                i.e., they go from high to low elevation.)