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Additional Tools

Obi Analysis

The following script will create an individual qpoe file (64x64 pixels) for each obi, with the filename containing the obi number. The obi times are read from the ASCII file 'obi_times.asc' (created in section 13.2.4). This script will then produce smoothed image files and send a contour plot to either the screen or the printer.

Run obidiv.cl to plot out the contour maps of each individual obi:

>xspatial
>xplot
>task obidiv=obidiv.cl

Here is a sample of the parameter settings:

qpfile = "rh70088100.qp"    Original Qpoe file
obi_list = "obi_times.asc"    File containing the obi times
out_files = "3C120"    Root name for output files: root??.qp
xpos = 4101    X source coordinate
ypos = 4068    Y source coordinate
gauss_sm = 2.54    Gaussian smooth sigma in pixels
cntr_lv = "5 25 50 75 95"    Contour levels (percent of peak)
(flist = )
(mode = "ql")

NOTES:
-------
-For printouts set this imcontour parameter ('epar imcont'):
graph_device = "stdplot"

-For a continuous dump of the contour plots to the screen, set:
graph_device=stdgraph
gclose=yes

>obidiv

Method for Visual Inspection
On rare occasions, it may be useful to examine each phase bin visually to evaluate the segments in order to decide if some should be deleted before restacking for the final result. We have found it useful to do this via contour diagrams of the source. This approach can be labor intensive if there are a large number of obis and phase bins. However, if you find that individual obis are reasonably well aligned and you opt for stable roll angle intervals (each containing many obis), then this method can be useful for weaker sources. This visual inspection method involves running the script described below to obtain contour plots of each phase bin; measuring centroids by eye on the contour diagram and evaluating the PRF of each segment in order to decide if some should be rejected; shifting each phase bin with 'qpshift', and finally restacking the segments with 'qpappend_ftsi'. This task is similar to 'phase_repos.cl' but without the source detection algorithm that determines the source position. The input file is the qpoe produced by 'qpphase'. The script will create an individual qpoe file for each phase bin interval. The qpoe file will be named by obi and phase number. As described for the task 'obidiv', an output image will be sent to the screen or printer for each file created.

>task phase_eval=phase_eval.cl
>xplot
>xspatial

With the parameters set as follows:

qpfile = "rh70088100_ph.qp"    Qpoe file output by qpphase
obi_list = "obi_times.asc"    File name containing the obi times
out_files = "3C120"    Root name for output files: root_obi??_ph??.qp
num_phase = 10    Number of phase bins
xpos = 4101    X source coordinate
ypos = 4068    Y source coordinate
gauss_sm = 2.54    Gaussian smooth sigma in pixels
cntr_lv = "5 25 50 75 95"    Contour levels
(flist = "")
(mode = "ql")

*** For selecting hardcopy or screen plots, see 'Obi Analysis' in this same section.***
>phase_eval


next up previous contents
Next: An Example - 3C Up: Spatial Corrections of ROSAT Previous: Dewobble Procedure: treating each
rsdc@cfa.harvard.edu
1998-06-10