/DEROTATOR angle system
Specify derotator angle for HERA
Real :: angle ! in units [deg] (!)
Character :: system !
Choices for system:
"Nasmyth"
"horizon"
"equatorial"
"frame" ! same as Nasmyth
"sky" ! same as equatorial
NOTES: The last 2 are for consistency with old control system and HERA conve
This option works only for RECEIVER HERA1 or RECEIVER HERA2 (of course it's
same angle for HERA1 and HERA2).