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cat_make xray.xspatial.eintools


NAME · USAGE · DESCRIPTION · PARAMETERS · ALGORITHM · EXAMPLES
TIME_REQUIREMENTS · BUGS · SEE_ALSO

NAME

cat_make -- Create a constant aspect table for an Einstein QPOE file.

USAGE

cat_make qpoefile catfile

DESCRIPTION

cat_make will read in the aspect information in the BLT records of the input QPOE file and group together aspect records which fall within the same "aspect bin". The final constant aspect table converts the Einstein aspect information into a more general WCS format.

The task will take into account any time filter placed on the QPOE file.

The task exp_make uses cat_make and cat2exp to create exposure masks for Einstein IPC images.

PARAMETERS

qpoefile = "" prompt = input QPOE file [root.qp]

The input qpoe file name. The extension ".qp" will be added to the file if there is no extension.

catfile = "" prompt = output constant aspect table [root_cat.tab]

The output constant aspect table. If no root is given, the output table file name will be the root of the reference QPOE file followed by the "_cat.tab" suffix. If the user supplies a name without an extension, the default extension will be "_cat.tab".

(aspx_res = 4.) [double]

The aspect x offset resolution (in pixels) for the binning. With a resolution of 4 pixels, aspect x offsets of -2.0 through 2.0 will be binned together, as will 2.0 through 6.0, etc.

(aspy_res = 4.) [double]

The aspect y offset resolution (in pixels) for the binning. With a resolution of 4 pixels, aspect y offsets of -2.0 through 2.0 will be binned together, as will 2.0 through 6.0, etc.

(aspr_res = 0.0087266463) [double]

The aspect roll offset resolution (in radians) for the binning. The default value corresponds to 0.5 degrees will, for instance, bin together all aspect roll offsets between -0.25 and 0.25 degrees.

(clobber = no) [boolean]

OK to overwrite the existing output file?

(display = 1) [int]

The display level. A setting of 0 should output no display (besides warnings), while settings above 3 are only useful for debugging.

ALGORITHM

Each BLT record in the QPOE file is time-filtered through the DEFFILT and the (possibly empty) user-supplied on-line QPOE filter. The aspect within the remaining BLT records contains four relevant quantities: aspect x offset (aspx), aspect y offset (aspy), aspect roll offset (aspr), and nominal roll (roll). These aspect values are binned together, following an algorithm modeled after one found in the Einstein Level One Processing file make_cah_cai.f .

For each aspect record, the first three values (aspx, aspy, aspr) are replaced by the center value of the resolution bin each falls into. If, for instance, the aspx resolution is 4.0 pixels, then all aspx values between -2.0 and 2.0 pixels will be replaced with 0.0 pixels, while all aspx values between 2.0 and 6.0 pixels will be replaced with 4.0 pixels, etc. The nominal roll is not changed.

Two aspect records are then combined if they have duplicate binned values. (Hence if two records have different nominal rolls, they will remain separate.) Each row of the final constant aspect table represents one collection of duplicate aspect records, with the final livetime being the sum of the aspect records' durations times the QPOE's dead time correction (DTCOR).

Note that the sum of all the livetimes in the CAT should be equal to the exposure time of the QPOE multiplied by the DTCOR (assuming no on-line time filters). There may be small discrepancies due to differences between BLT records and GTI intervals. (For instance, for Revision 0 IPC QPOE files, each BLT record is missing .32 seconds. Other BLT records in both Revision 0 and Revision 1 files may be missing up to 41 seconds.)

Each row is then converted into a WCS-style format, describing the map between PROS detector coordinates and the final sky coordinates described by the aspect row and the QPOE WCS information.

For Revision 1 IPC QPOE files, all BLT records are used, even if the aspect records were considered "bad" (quality=3). (The user must use a time filter to screen out these records.)

EXAMPLES

Use cat_make to create a constant aspect table for a Revision 1 IPC QPOE file i196.qp:

ei> cat_make
input QPOE file [root.qp]: i196.qp
output CAT file [root_cat.tab]: 

Created constant aspect table i196_cat.tab with 14 row(s).
ei> tprint i196_cat.tab prparam=yes
  Table i196_cat.tab  Mon 16:11:37 28-Feb-94

RA_NOM   r 11.52499       
DEC_NOM  r 1.099999       
RCTYP1   t RA--TAN
RCTYP2   t DEC-TAN
RCRPX1   d 512.                     
RCRPX2   d 513.0000000000006        
RCDLT1   d -0.002222222276032004    
RCDLT2   d 0.002222222276032004     
ASPX_RES d 4.                       
ASPY_RES d 4.                       
ASPR_RES d 0.008726646300000007     
COMMENT1 t This constant aspect table is an intermediate file used
COMMENT2 t in creating an exposure mask in the EINTOOLS package.
COMMENT3 t The aspect of the input qpoe file has been grouped according
COMMENT4 t to the input resolutions, then converted into WCS format.
COMMENT5 t See the help page for CAT_MAKE for more information.
HISTORY  t CAT_MAKE: i196.qp -> i196_cat.tab

(row)           LIVTI          RCRVL1          RCRVL2          RCROT2
                  sec             deg             deg             deg

    1         9.28020        11.50515         1.10117        66.80892
    2         8.35218        11.50164         1.10934        66.80892
    3         4.02142        11.51332         1.10467        66.80892
    4         3.09340        11.51682         1.09650        66.80892
    5      2149.60260        11.52499         1.10000        66.80892
    6        11.75491        11.51245         1.06443        64.41191
    7         4.64010        11.50862         1.07245        64.41191
    8         1.54670        11.51663         1.07629        64.41191
    9         3.40274        11.51279         1.08430        64.41191
   10         6.18680        11.52081         1.08814        64.41191
   11      3432.43498        11.52499         1.10000        64.41191
   12        11.75491        11.53651         1.07595        64.41191
   13         6.49614        11.53267         1.08396        64.41191
   14         6.18680        11.52883         1.09198        64.41191

TIME REQUIREMENTS

This task takes under 5 seconds on a Sparc to create the constant aspect table from a QPOE file with 14 BLT records. It takes about 90 seconds on a Sparc for a QPOE file with 187 BLT records.

BUGS

The WCS information in the constant aspect table depends on the WCS information in the QPOE file. If the WCS in the QPOE has been modified (via qplintran or wcsedit ) the constant aspect table may be incorrect.

SEE ALSO

See cat2exp for creating an exposure mask from a constant aspect table.

Use "help explain_cat" for more information on the contents of constant aspect tables.

See also exp_make , a script which calls both cat_make and cat2exp .


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