H,Y Sky Flats
(1) Set the telescope up for twilight skies - 1h E (When the twilight field
runs near the Milky Way, especially near 18h, the faint fields will be
too crowded with stars. We have to move the field.) MAKE SURE THE
TELESCOPE IS NOT TRACKING. DON'T MOVE THE TELESCOPE BETWEEN THE FRAMES
DURING THE WHOLE PROCESS OF IR SKY FLATS.
(2) Starting around 10min BEFORE sunset, start taking 4s exposures in H.
When the count level reaches 5000 ADU, run
H_Junk.obs
H_Bright.obs
(3) Around 1.5 min BEFORE sunset, start taking 4s exposures in Y. When the count
level reaches 5000 ADU, run
Y_Junk.obs
Y_Bright.obs
(4) Later than 10min AFTER sunset, run
H_Junk.obs
H_Faint.obs
(5) Later than 12min AFTER sunset, run
Y_Junk.obs
Y_Faint.obs
(6) turn on the TRACKING of the telescope.
THE OWNER CODES FOR IR SKY FLATS ARE "ALL".