Gold Level 1D 140, 152, and 156 nm Versus Altitude Occultation Plots

The Level 1C Dayside Disk Images are interrupted via stored instrument commands when
target stars suitable for occultation measurements approach either limb.
To perform the occultation measurement, the slit mechanism inserts the 1 degree wide occultation (OCC)
slit at the spectrometer focal plane, and the scan mirrors slew the Field of View to the star.
The mirror is centered at a 225 km tangent point altitude. Occultations require 6 minutes to
execute (30 seconds to configure the instrument, 30 seconds for uncertainty in timing and pointing,
4 minutes for the actual occultation, 30 seconds for uncertainty in timing and pointing, and 30
seconds to return to HR slit). Once the occultation is complete, the HR slit is inserted, the scan
mirror returns to its departure point in the original mapping observation. By choice GOLD is limited
to performing ~10 occultations a day for most of the year,
reducing the dayside mapping duty cycle by ~5%.