IMPORT- Imports FITS information into images

Description:

This routine imports FITS information into the CCDPACK extension of a list of images. FITS information (probably provided by the instrument/telescope control systems) can be used to specify certain parameters which are required by CCDPACK to perform "automated" reductions. These might cover such items as the type of data (target, flatfield, bias frame etc.), the Analogue-to-Digital Conversion factor, the nominal readout noise, the position of any bias strips (over-scan regions) etc.

The import is controlled by a "table" which specifies how FITS keyword values should be interpreted. This allows the evaluation of functions containing many FITS keywords as well as the mapping of CCDPACK recognised character items to arbitrary strings.

Usage:

import in table

Parameters:

IN = LITERAL (Read)

A list of image names which contain the raw bias frame data. The image names should be separated by commas and may include wildcards.

LOGFILE = FILENAME (Read)

Name of the CCDPACK logfile. If a null (!) value is given for this parameter then no logfile will be written, regardless of the value of the LOGTO parameter.

If the logging system has been initialised using CCDSETUP then the value specified there will be used. Otherwise, the default is "CCDPACK.LOG". [CCDPACK.LOG]

LOGTO = LITERAL (Read)

Every CCDPACK application has the ability to log its output for future reference as well as for display on the terminal. This parameter controls this process, and may be set to any unique abbreviation of the following:

• TERMINAL - Send output to the terminal only

• LOGFILE - Send output to the logfile only (see the LOGFILE parameter)

• BOTH - Send output to both the terminal and the logfile

• NEITHER - Produce no output at all

If the logging system has been initialised using CCDSETUP then the value specified there will be used. Otherwise, the default is "BOTH". [BOTH]

NAMELIST = LITERAL (Read)

The name of a file to contain a listing of the name of the input images. This is intended to be of use when using these same names with other applications (such as SCHEDULE). [!]

TABLE = LITERAL (Read)

The name of the table containing the description of how FITS keyword values are to be translated into CCDPACK extension items. See the topic "Table Format" for information on how to create a translation table. ['import.tab']

Examples:

import in='$*$' table=$CCDPACK_DIR/WHTSKY.DAT

This example shows all the images in the current directory being processed using the import control table $CCDPACK_DIR/WHTSKY.DAT.

See also :

PRESENT.

Table Format :

The import control (translation) table is an ordinary text file which contains instructions on how to transfer FITS information from the FITS extension to the CCDPACK extension of an image. "Translation" is required since no standard interpretation of FITS keywords can be made and because the items which may be required can be compounds of single FITS keyword values.

In its most simple format a FITS control table is just a series of lines which contain the names of CCDPACK extension items and the names of the FITS keywords to which they map.

Extension-item

FITS-keyword

If the HDS type of the destination Extension-item is known this may be included.

Extension-item

_HDS-type

FITS-keyword

Normally this is inferred. This is the format used by the KAPPA application FITSIMP (as of KAPPA version 0.8-6U). Extension items are the names of CCDPACK items (such as FTYPE, FILTER etc.). These may be heirarchical, e.g. TIMES.DARK. Note that they exclude the "NDF_NAME.MORE.CCDPACK." part of the extension path name.

To allow functions of FITS-keywords to be possible a second "declarative" form of statement is necessary.

_HDS-type

FITS-keyword

So for instance if you wanted to derive an exposure time for an observation which was given in milliseconds and which you wanted to convert into seconds you would use this sequence of commands:

_INTEGER	EXPOSURE
TIMES.DARK	_DOUBLE	1000.0D0$*$EXPOSURE

The "_INTEGER EXPOSURE" tells this application to find a FITS keyword of EXPOSURE and extract its value as an integer. If you wanted to estimate the dark time from a knowledge of the start and end times (TAI0 and TAI1):

_DOUBLE	TAI0
_DOUBLE	TAI1
TIMES.DARK	_DOUBLE	(TAI1-TAI0)

The function may use any of the usual Fortran operators; +, -, *, /, ** and many others that are supported by the TRANSFORM package (SUN/61).

Functions are allowed to not contain any FITS-keywords in which case the extension item will be assigned to the value, so for instance numerical constants may be given:

EXTENT.MINX	_INTEGER	1
EXTENT.MINY	_INTEGER	1

In this way import tables could actually be used to set all the required values in the CCDPACK extension (but see PRESENT also).

Characters strings cannot be manipulated by functions so a single special format for translating their values is provided. The name of the destination extension item and (optionally) its type are given as usual followed by a FITS-keyword which contains the string to be translated. This is then followed by statements which translate an "input" string into an "output" string, i.e.:

FITS1 = Ext1 FITS2 = Ext2 FITS3 = Ext3 ... FITSn = Extn

So for instance if you wanted to translate frame types to those recognised by CCDPACK you might use something like:

FTYPE	_CHAR	OBSTYPE OBJECT=TARGET -
		FF=FLAT -
		ZERO=BIAS

Which would compare the value of the FITS-keyword OBSTYPE with the strings "OBJECT", "FF" and "ZERO" (case insensitive) and convert these into the values in the right-hand side of the equals sign.

Logical data types are restricted to a single keyword whose value must be "YES", "TRUE", "T", "Y" for TRUE or "NO", "FALSE", "N", "F".

The FITS keywords may be hierarchical, and on the whole are specified simply by giving their name in the normal way. However, there is one special case: if the value of a FITS header is known to be a string of the form '[A:B,C:D]' the numbers A, B, C and D may be extracted individually by appending '<X1>', '<X2>', '<Y1>' or '<Y2>' respectively to the name of the keyword. Hence:

EXTENT.MINX	TRIMSEC<X1>
EXTENT.MAXX	TRIMSEC<X2>

would set the extents from the first two fields of a suitably formatted TRIMSEC header.

Fields in the table may be separated by commas if desired, any amount of white space and tabs are also allowed. Comments may be placed anywhere and should start with the characters "#" or "!". Continuation onto a new line is indicated by use of "-".

CCDPACK extension items :

The CCDPACK extension of an image may contain the following items. The names and types of the extension items are those as used in import tables. More complete descriptions of the items can be found with the applications that use these values.

Name	HDS data type	Description
ADC	_DOUBLE	The analogue to digital conversion factor.
BOUNDS.END1	_INTEGER	The end row or column of the first bias strip region.
BOUNDS.END2	_INTEGER	The end row or column of the second bias strip region.
BOUNDS.START1	_INTEGER	The first row or column of the first bias strip region.
BOUNDS.START2	_INTEGER	The first row or column of the second bias strip region.
DEFERRED	_DOUBLE	The deferred charge.
DIRECTION	_CHAR	The "readout" direction (X or Y).
EXTENT.MAXX	_INTEGER	Maximum X coordinate of useful region.
EXTENT.MAXY	_INTEGER	Maximum Y coordinate of useful region.
EXTENT.MINX	_INTEGER	Minimum X coordinate of useful region.
EXTENT.MINY	_INTEGER	Minimum Y coordinate of useful region.
FILTER	_CHAR	Filter name.
FTYPE	_CHAR	Frame type (TARGET, BIAS, FLAT, DARK or FLASH)
RNOISE	_DOUBLE	Readout noise (ADUs)
SATURATION	_DOUBLE	Pixel saturation count.
TIMES.DARK	_DOUBLE	Dark count time.
TIMES.FLASH	_DOUBLE	Pre-flash time.