K,J 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 35min BEFORE sunset, start taking 4s exposures in K.
When the count level reaches 5000 ADU, run:
K_Junk.obs
K_Bright.obs
(3) Around 5min BEFORE sunset, start taking 4s exposures in J. When the count
level reaches 5000 ADU, run
J_Junk.obs
J_Bright.obs
(4) Later than 7min AFTER sunset, run
K_Junk.obs
K_Faint.obs
(5) Later than 10min AFTER sunset, run
J_Junk.obs
J_Faint.obs
The faint flats should have around 500 counts.
(6) turn on the TRACKING of the telescope.
THE OWNER CODES FOR IR SKY FLATS ARE "ALL".