SPHERE/ZIMPOL: Reference frames

SPHERE ZIMPOL reference frames

Calibrations are taken for the all three ZIMPOL read modes

• StandardImaging
• SlowPolarimetry
• FastPolarimetry

The basic ZIMPOL optical components are stored in the following keys:

• The dual beam filters INS3.OPTI5.NAME and INS3.OPTI6.NAME
  

ZIMPOL bias and dark frames:

ZIMPOL bias and dark frames are acquired in regular time intervals for all three read modes.
Bias frames are 0 sec exposed (EXPTIME = DET.DIT1 = 0) and repeated 40 times (NDIT=40) resulting in a fits data cube with NAXIS3=40 planes.
Dark frames are 100 sec exposed (EXPTIME = DET.DIT1 = 100) and repeated zero or one time resulting in a fits data file with NAXIS=2 or a data cube with NAXIS=3 and NAXIS3=2.

bias
DET.READ.CURNAME	StandardImaging	SlowPolarimetry	FastPolarimetry
DET.DIT1	0	0	0
DET.NDIT (=NAXIS3)	40	40	40
bias (chip1 and chip2)
one plane of the raw frame cube * [all are 4-10 MB]	fits	fits	fits
headers	hdr	hdr	hdr
products
dark
DET.READ.CURNAME	StandardImaging	SlowPolarimetry	FastPolarimetry
DET.DIT1	100	100	100
DET.NDIT (=NAXIS3)	1	1	1
dark (chip1 and chip2)
one plane of the raw frame cube * [all are 17 MB]	fits	fits	fits
headers	hdr	hdr	hdr
products

 

ZIMPOL flat frames:

ZIMPOL flat farmes are acquired in regular time intervals for all three read modes.
Flat frames come per filter located in INS3.OPTI5.NAME and IN3.OPTI6.NAME

flat
DET.READ.CURNAME	StandardImaging	SlowPolarimetry	FastPolarimetry
INS3.OPTI5.NAME	N_R	N_R	N_R
N_R filter flat (chip1 and chip2)
one plane of the raw frame cube * [all are 4-10 MB]	fits	fits	fits
headers	hdr	hdr	hdr
products