The Analogue-to-Digital conversion factor. CCD readout values are usually given in Analogue-to-Digital Units (ADUs). The ADC factor is the value which converts ADUs back to the number of electrons which were present in each pixel in the CCD after the integration had finished. This value is required to allow proper estimates of the inherent noise associated with each readout value. CCDPACK makes these estimates and stores them in the variance component of the final images. Not supplying a value for this parameter (if prompted) may be a valid response if variances are not to be generated.

This parameter normally accesses the value of the related CCDPACK global association. This behaviour can only be superceded if ADC=value is used on the command-line or if a prompt is forced (using the PROMPT keyword). The value of this parameter will be entered into the extension of the input images only if MODIFY is TRUE or the related extension item does not exist. [!]

Whether or not to prompt for a dark exposure time for the input images which require one. [Dynamic default, TRUE if dark count frames are given, FALSE otherwise]

Whether or not to prompt for a pre-flash exposure time for the input images which require one. [Dynamic default, TRUE if pre-flash frames are given, FALSE otherwise]

A list of the names of the images which contain the raw bias data. These are the images which are to used to produce a "master" bias image. On exit these images will have their FTYPE extension item set to the value "BIAS". [!]

If no raw bias frames exist and the data does not have any bias strips, then the only way to remove the bias contribution is to subtract a constant. If your data has already had its bias contribution subtracted and you want to process it using CCDPACK (so that you can generate variances for instance) then set this value to zero. This parameter defaults to ! and is not prompted for so the only way that a value can be supplied is on the command-line or by using the PROMPT keyword. [!]

The bounds of the detector bias strips (if any exist). The bounds (if given) should be in pixel indices and be given in pairs up to a limit of 2. The sense of the bounds is along the readout direction. For example, 2,16,400,416 means that the bias strips are located between pixels 2 to 16 and 400 to 416 inclusive along the readout direction. The bias strips are used to either offset the master bias image or as an estimate of the bias which is to be interpolated across the image in some way (see DEBIAS). Not supplying values for this parameter may be a valid response if the bias frame is to be directly subtracted from the data without offsetting or if a single constant is to be used as the bias value for the whole image.

This parameter normally accesses the value of the related CCDPACK global association. This behaviour can only be superceded if BOUNDS=[value,...] is used on the command-line or if a prompt is forced (using the PROMPT keyword). The value of this parameter will be entered into the extension of the input images only if MODIFY is TRUE or the related extension item does not exist. [!]

A list of the names of the images which contain the raw dark count data. These are the images which are to used to produce a "master" dark counts image. On exit these images will have their FTYPE extension item set to the value "DARK". [!]

The time for which the data in the current image collected dark count electrons. The dark count is basically charge which accumulates in the detector pixels due to thermal noise. The effect of dark current is to produce an additive quantity to the electron count in each pixel. Most modern devices only produce a few ADU (or less) counts per pixel per hour and so this effect can generally be ignored. This, however, is not the case for Infra-Red detectors.

The value given does not need to be a number of seconds or minutes and can be ratio of some kind, as long as it is consistently used for all images (so if all your images have the same darktime then the value 1 could be used). Images which have no dark count should be given a DARKTIME of 0. This parameter is only used if ADDDARK is TRUE. [!]

The deferred charge value. Often known as the "fat" or "skinny" zero (just for confusion). This is actually the charge which is not transferred from a CCD pixel when the device is read out. Usually this is zero or negligible and is only included for completeness and for processing very old data.

This parameter normally accesses the value of the related CCDPACK global association. This behaviour can only be superceded if DEFERRED=value is used on the command-line or if a prompt is forced (using the PROMPT keyword). The value of this parameter will be entered into the extension of the input images only if MODIFY is TRUE or the related extension item does not exist. [!]

The readout direction of the detector. This may take the values X or Y. A value of X indicates that the readout direction is along the first (horizontal) direction, an Y indicates that the readout direction is along the direction perpendicular to the X axis.

This parameter normally accesses the value of the related CCDPACK global association. This behaviour can only be superceded if DIRECTION=value is used on the command-line or if a prompt is forced (using the PROMPT keyword). The value of this parameter will be entered into the extension of the input images only if MODIFY is TRUE or the related extension item does not exist. [!]

The extent of the useful detector area in pixel indices. The extent is defined as a range in X values and a range in Y values (XMIN, XMAX, YMIN, YMAX). These define a section of an image (see SUN/33). Any parts of the detector surface area outside of this region will not be present in the final output. This is useful for excluding bias strips, badly vignetted parts etc.

This parameter normally accesses the value of the related CCDPACK global association. This behaviour can only be superceded if EXTENT=[XMIN, XMAX, YMIN, YMAX] is used on the command-line or if a prompt is forced (using the PROMPT keyword). The value of this parameter will be entered into the extension of the input images only if MODIFY is TRUE or the related extension item does not exist. [!]

The filter name associated with the current image. The filter name is stored in the extension item FILTER and is used when determining which flatfields should be used for which data. images with a frame type which is independent of the filter will not use this parameter. The filter type is a case sensitive string. [Current value]

A list of the names of the images which contain the raw pre-flash correction data. These are the images which are to used to produce a "master" pre-flash correction image. On exit these images will have their FTYPE extension item set to the value "FLASH". [!]

The time for which the data in the current image was exposed to pre-flash.

The value given does not need to be a number of seconds or minutes and can be ratio of some kind, as long as it is consistently used for all images (so if all your images have the same darktime then the value 1 could be used). Images which have no pre-flash should be given a FLASHTIME of 0. This parameter is only used if ADDFLASH is TRUE. [!]

A list of the names of the images which contain the raw flatfield data. These are the images which are to used to produce "master" flatfields (one for each filter type). On exit these images will have their FTYPE extension item set to the value "FLAT". [!]

The "frame" type of the current image. Each image is processed in turn and if SIMPLE is TRUE and a frame type extension item does not exist then this parameter will be used to prompt for a value. A prompt will also be made if SIMPLE is TRUE and MODIFY is TRUE regardless of whether the item already exists or not. If SIMPLE is FALSE then this parameter will not be used. [Current value]

A list of the names of the images which contain the raw CCD data. Images entered using this parameter must already have the correct "frame type" information (extension item FTYPE) entered into their CCDPACK extensions. This parameter is only used if SIMPLE is TRUE.

The image names should be separated by commas and may include wildcards.

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]

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]

The name of a master bias frame. If this has been created by CCDPACK then there is no need to present it. This parameter is designed for the import of frames created by other packages. [!]

The name of a master dark counts frame. If this has been created by CCDPACK then there is no need to present it (unless for some reason it has been assigned the wrong frame type). This parameter is designed for the import of frames created by other packages.

The name of a master pre-flash frame. If this has been created by CCDPACK then there is no need to present it (unless for some reason it has been assigned the wrong frame type). This parameter is designed for the import of frames created by other packages. [!]

The names of a set of master flatfield frames (one for each filter type used). If these have been created by CCDPACK then there is no need to present them (unless for some reason they have been assigned the wrong frame type or filter). This parameter is designed for the import of frames created by other packages (such as those that specifically process spectral data). [!]

If this parameter is TRUE then prompts will be made for all the master calibration types (MASTERBIAS, MASTERDARK, MASTERFLAT and MASTERFLASH). [FALSE]

If the input images already contain information in their CCDPACK extensions, then this parameter controls whether this information will be overwritten (if a new value exists) or not. [TRUE]

Whether or not the names of the input images, their frame types, filters and related exposure factors are all given in response to the IN parameter (SIMPLE must be TRUE). If this option is selected then the parameters FTYPE, FILTER, DARKTIME and FLASHTIME will be set up with these values as defaults. If MODIFY is TRUE then you will be given an opportunity to modify them, otherwise these values will be entered into the image CCDPACK extensions.

The input record format is five fields separated by commas. These are:

• 1 Image name

• 2 Frame type

• 3 Filter name

• 4 Dark exposure time

• 5 Flash exposure time

The latter three fields can be specified as "!" in which case they are not set (they may not be relevant). Multiple records can be entered and can be read in from a text file. So for instance if the file "XREDUCE.NDFS" had the following as its contents:

Then it would be invoked using parameters

• SIMPLE MULTIENTRY IN=$$^XREDUCE.NDFS

This parameter is intended as an aid when using this program non-interactively (i.e. from scripts) and shouldn’t normally be used, hence its default is FALSE and this can only be overridden by assignment on the command line or in response to a forced prompt. [FALSE]

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). [!]

If the input data have the same dark count exposure time then this parameter may be set to inhibit repeated prompting for an exposure for every frame. This parameter is of particular use when running from scripts. [FALSE]

If the input data have only one filter type then this parameter may be set to inhibit repeated prompting for a filter name for every frame (that is filter dependent). This parameter is of particular use when running from scripts. [FALSE]

If the input data have the same pre-flash exposure time then this parameter may be set to inhibit repeated prompting for an exposure for every frame. This parameter is of particular use when running from scripts. [FALSE]

The readout noise of the detector (in ADUs). Usually the readout noise of a detector is estimated by the observatory at which the data was taken and this is the value which should be supplied. Not supplying a value for this parameter may be a valid response if variances are not to be generated.

This parameter normally accesses the value of the related CCDPACK global association (which is the readout noise value). This behaviour can only be superceded if RNOISE=value is used on the command-line or if a prompt is forced (using the PROMPT keyword). The value of this parameter will be entered into the extension of the input images only if MODIFY is TRUE or the related extension item does not exist. [!]

The saturation value of the detector pixels (in ADUs).

This parameter normally accesses the value of the related CCDPACK global association. This behaviour can only be superceded if SATURATION=value is used on the command-line or if a prompt is forced (using the PROMPT keyword). The value of this parameter will be entered into the extension of the input images only if MODIFY is TRUE or the related extension item does not exist. [!]

Whether or not the input images already contain "frame type" (extension item FTYPE) information in their CCDPACK extensions or not. Usually images to be presented to CCDPACK do not contain this information, unless it has been imported from FITS information using IMPORT, or the images have already been presented and this pass is to modify existing extension items. [FALSE]

A list of the names of the images which contain the "target" data. These are the images which contain the images or spectra etc. On exit these images will have their FTYPE extension item set to the value "TARGET". [!]

If a master bias frame is given, then this parameter indicates whether or not it has a mean value of zero. If SIMPLE and MULTIENTRY are TRUE then this value (TRUE or FALSE) can be entered as the fourth field to the IN parameter. [FALSE]