gvcalc \- calculation of velocity from sets of MDI filtergrams taken through a heliostat.SH SYNOPSIS
.B gvcalc
\fI[-qvrf] [argument= value ...]\f
.SH DESCRIPTION
\fIgvcalc\fR calculates Dopplergrams from sets of MDI filtergrams takenthrough the heliostat ground testing system. The filtergrams are assumedpresnt in groups of five at tuning positions 0 through 4 (nominal continuum,-120 mA, -40 mA, +40 mA, +120 mA from filter transmission center,respectively). The location of the image center is found for theindividual filtergrams using the limb
finder \fIfit_limb()\fR and the average and rms center is saved. The imagesare not registered prior to the doppler shift calculation.The Doppler velocity is computed using the \fImdi_vcalc()\fR function.
The resulting image is inverted unless the no-flip
flag (-f) is given. The position angle is computed based on the observation time and date but the Dopplergram is not rotated. The determined radius is used to differentiate full disk from calmode
and high-res images. If the image is determined to be a full disk measurement a calibration Doppler image is subtracted. If the raw flag (-r) is given, the calibration image is not subtracted
and the ephemeris corrections (subtraction of Earth's spin and orbital motion) are not made.
The \fB\-q\fR option prints out the list of required arguments and their
default or environmental values, then quits. The \fB\-v\fR option sets \fIverbose\fR mode, redirecting history from \fIstdout\fR to \fIstderr\fR.
.NXR ""
.SH OPTIONS
.NXR "module command" "options"
.IP \fBin0=\fIname\fR 20
dataset of filtergrams at tuning position 0 (no default) .IP \fBin1=\fIname\fR 20
dataset of filtergrams at tuning position 1 (no default) .IP \fBin2=\fIname\fR 20
dataset of filtergrams at tuning position 2 (no default) .IP \fBin3=\fIname\fR 20
dataset of filtergrams at tuning position 3 (no default) .IP \fBin4=\fIname\fR 20
dataset of filtergrams at tuning position 4 (no default) .IP \fBoutlog=\fIname\fR 20
name of log file (default: /home/soi/data/logs/V_mdi.log) .IP \fBout=\fIname\fR 20
output dataset (default: Vobs.fits)
.IP \fBcalib=\fIname\fR 20
calibration dataset (default: /home/soi/calib/calib.256.fits) .IP \fBvtable=\fIname\fR 20
velocity lookup table (default: /home/soi/tables/VTable.fits) .IP \fBfrac_lenside=\fIReal\fR 20
parameter for limb finding (default: 70/1024) .IP \fBfrac_box=\fIReal\fR 20
parameter for limb finding (default: 200/1024) .IP \fBfrac_thresh=\fIReal\fR 20
parameter for limb finding (default: 0.3)
.SH KEYWORDS
The following keywords are set in the output file:
.IP \fBGVCALC_VERS\fR 20
Current gvcalc version.
.IP \fBVTABLE_VERS\fR 20
VTable used in Doppler velocity calculation.
.IP \fBVRES\fR 20
Velocity resolution in m/s.
.IP \fBISFLIPT\fR 20
Boolean true if image flipped top to bottom.
.IP \fBX0\fR 20
Location of image center in pixels.
.IP \fBY0\fR 20
Location of image center in pixels.
.IP \fBX0_RMS\fR 20
Standard deviation of image center determination.
.IP \fBY0_RMS\fR 20
Standard deviation of image center determination.
.IP \fBRMAJOR\fR 20
Determined image radius in pixels.
.IP \fBR_RMS\fR 20
Standard deviation of image radius.
.IP \fBP\fR 20
P-angle to rotate image CW for N at top, E to left.
.IP \fBB0\fR 20
Latitude of sub-earth point.
.IP \fBV_ORBIT\fR 20
Line-of-sight velocity of MDI.
.IP \fBIMAGE_T\fR 20
Time of image observation.
.IP \fBMDI_PATH\fR 20
FullDisk or HighRes indicator.
.IP \fBMDI_DATA\fR 20
Observable indicator == "Doppler".
.IP \fBCALIBFN\fR 20
Calibration file path.
.IP \fBVTABLE_NAME\fR 20
Velocity lookup table filename.
.IP \fBLOGFN\fR 20
Log file name.
.IP \fBMDI_MODE\fR 20
Image or cal mode indicator, "Image" or "Calib".
.SH EXAMPLES
.NXR(e) ""
.SH FILES
/home/soi/tables/VTable.fits
.SH SEE ALSO
fit_limb(3), mdi_vcalc(3)
.SH DIAGNOSTICS
.SH BUGS
It would be a lot more convenient to have the associated filtergrams
collected in a single dataset.
The parameters used by the limb finder should not have to be set as
arguments.
Standard library IO functions are used to create output log. The name
of the output log file should be determined from the input data; without a default.
The calib image to be subtracted is only correct for 256x256 images.
There is no correct recognition of High-Res images.
.SH AUTHORS
Phil Scherrer, Rick Bogart, Kay Leibrand, Luiz Sa, Katie Scott
.rs
.SH HISTORY
1994-02-14 SOI Version 0.8
.#$Id: gvcalc.1,v 1.3 1994/03/03 20:25:29 phil Exp $ .#$Source: /home/soi/CM/man/man1/RCS/gvcalc.1,v $ .#$Author: phil $