bvitpreview – Preview BVIT data and select object and background regions
bvitpreview imstart imend outfile (tgt_col) (cmp_col) (tgt_lw) (cmp_lw) (cmap) (scale) (contrast) (clobber) (logfile) (verbose) (debug)
This tool is used for selecting the target and comparison positions and their and radii as well as their corresponding background regions.
All position parameters may be entered manually or captured by clicking on the image.
The output is an ascii table with 12 columns and 2 rows. An example is provided below:
# star x y x_end y_end r r_bkg1 r_bkg2 x1 y1 x2 y2
# -------------------------------------------------------
1 3 193 11 120 13 14 10 0 0 10 10
2 3 37 12 133 13 14 20 20 20 50 40
Column 1 contains a numeric flag for the star which is either 1 or 2. Column 3 is the position of a source in (binned) CCD pixel units in the x-direction, or if you prefer the column number. Column 4 refers to the corresponding y- or row coordinate. Columns 5 and 6 contain the end positions of the objects used for drift correction by linear interpolation. Column 7 contains the radius of the circular extraction region for the source counts. Columns 8 and 9 contain the inner and outer radii of the annulus used to extract background counts for each source. The last four columns specify the rectangular region used for background subtraction used if this mode is selected.
–> bvitpreview imstart = “OYCar_start” imend = “OYCar_end” outfile = “bvit.conf” tgt_col = “g” cmp_col = “r” tgt_lw = 2 cmp_lw = 2 cmap=”jet” scale=”zscale” contrast=0.1 clobber=y logfile=salt.log verbose=y debug=no
Then click on the capture button next to target position and click on the target. Click on the target radius position capture button and click next to the target to the point where you want the target region to extend. Click on the target end position capture button and click on the target in the second image. Now click the target background tab and select a background type. If annulus is selected click on the annulus capture button and click twice next to the target in the image. The first click selects the inner radius of the target background annulus and the second click the outer radius. If the region type is selected click on the region capture button and also click on the image twice to select the opposite corners of the rectangle.
Repeat this procedure for the comparison object.
In order to fine tune the parameters just repeat the desired step (in any order) or type the values in manually.
Optionally you may enable the lock button (broken chain icon) to ensure the target and comparison (or their background regions) always have the same size.
Finally click save to save the configuration file and quit the task.
If anything goes wrong just click cancel to ignore changes and quit.
Should load in maximum of 5 seconds on any recent machine. Main time consumption is in loading the fits images.