Possibility of amplifier-dependent data reduction for NOTCAM

To facilitate the amplifier-dependent data reduction using the IRAF mscred package, several keywords have been added to the primary header. The extra NOTCAM keywords hold information on the amplifier characteristics, and the layout of the amplifier mosaic. Together with a special translation file these keywords can be used to create multiextension format from images with multiple amplifier readouts recorded as sections of a single image. See example below using mkmsc from the IRAF mscred package.

Special NOTCAM keywords in the primary header

For keywords GAINn, RDNOISEn, CCDSEDCn, DATASECn, TRIMSECn, CRXn, CRYn:
keyword1 corresponds to amplifier Q0
keyword2 corresponds to amplifier Q1
keyword3 corresponds to amplifier Q3
keyword4 corresponds to amplifier Q2

Keyword name	Value	Description
QCDDATE	'2005-10-26'	Amplifier characteristics reference date
GAIN1	2.18E+00	[e-/ADU] Gain
GAIN2	2.19E+00	[e-/ADU] Gain
GAIN3	2.17E+00	[e-/ADU] Gain
GAIN4	2.19E+00	[e-/ADU] Gain
RDNOISE1	1.07E+01	[e-] Read-out noise
RDNOISE2	1.00E+01	[e-] Read-out noise
RDNOISE3	1.19E+01	[e-] Read-out noise
RDNOISE4	1.11E+01	[e-] Read-out noise
DETSEC1	'[1:512,1:512]'	Location in final mosaic
DETSEC2	'[513:1024,1:512]'	Location in final mosaic
DETSEC3	'[1:512,513:1024]'	Location in final mosaic
DETSEC4	'[513:1024, 513:1024]'	Location in final mosaic
CCDSEC1	'[1:512,1:512]'	Location in amplifier mosaic
CCDSEC2	'[513:1024,1:512]'	Location in amplifier mosaic
CCDSEC3	'[1:512,513:1024]'	Location in amplifier mosaic
CCDSEC4	'[513:1024, 513:1024]'	Location in amplifier mosaic
DATASEC1	'[1:512,1:512]'	Location of data pixels
DATASEC2	'[513:1024,1:512]'	Location of data pixels
DATASEC3	'[1:512,513:1024]'	Location of data pixels
DATASEC4	'[513:1024, 513:1024]'	Location of data pixels
TRIMSEC1	'[1:512,1:512]'	Location of useful data
TRIMSEC2	'[513:1024,1:512]'	Location of useful data
TRIMSEC3	'[1:512,513:1024]'	Location of useful data
TRIMSEC4	'[513:1024, 513:1024]'	Location of useful data
CRX1	5.310E+02	Reference pixel on 1st axis
CRX2	1.900E+01	Reference pixel on 1st axis
CRX3	5.310E+02	Reference pixel on 1st axis
CRX4	1.900E+01	Reference pixel on 1st axis
CRY1	5.432E+02	Reference pixel on 2nd axis
CRY2	5.432E+02	Reference pixel on 2nd axis
CRY3	3.120E+01	Reference pixel on 2nd axis
CRY4	3.120E+01	Reference pixel on 2nd axis

Example: creating a multi-extension FITS file suitable for use with the MSCRED package, from images with multiple amplifier readouts recorded as sections of a single image

Download the special translation file and save it in a directory where IRAF can read it.
Start IRAF in the normal way.
Load the MSCRED (Mosaic Reduction) package by typing:
mscred
mkmsc nc050062_notcam.fits[3] mosaic.fits description="notcam.dat"

In the command above mkmsc transforms the third data extension of the datafile nc050062_notcam.fits into a new multi-extension file with 4 data extensions (one extension for each amplifier). The translation file notcam.dat is used to map keywords from the primary header into new keywords in the data extensions of the output mef file mosaic.fits. This new mef file can be further processed with tasks from the IRAF mscred package. See also reduction notes for MOSCA mef data using MSCRED.