slotpreview – Preview SALT slotmode data and select object and background regions
slotpreview images outfile ignorexp (tgt_col) (cmp_col) (tgt_lw) (cmp_lw) (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 11 columns and 2 rows. An example is provided below:
# object amp x y r r1 r2 x1 y1 x2 y2
# ------------------------------------------
1 3 193 11 12 13 14 0 0 0 0
2 2 37 12 13 0 0 20 20 40 50
Column 1 contains a numeric flag for the star which is either 1 or 2. Column 2 is the amplifier containing the object, for slotmode this is a number between 1 and 4. 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. Column 4 contains the radius of the circular extraction region for the source counts. Columns 5 and 6 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.
–> slotpreview images = “@images.lst” outfile = “slot.conf” ignorexp = 6 tgt_col = “g” cmp_col = “r” tgt_lw = 2 cmp_lw = 2 clobber=y logfile=salt.log verbose=y
First click next until you find the exposure that contains the target. Then click on the capture button next to target position and click on the target. The marker is automatically recentered on the centroid of the object, if this is not desired deselect the recenter checkbox. 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. 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. Because of strong vignetting in the slotmode data it may be usefull to center the background region vertically, to do this automatically enable the centering button on the background selection tab. This changes the capture behaviour slightly, instead of specifying the vertices directly the distance of the cursor to the center line of the image is used on both sides of the line to set the y coordinate of the vertices the behaviour in the x direction is left unchanged.
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.
Virtually untested, please help here.
Send feedback and bug reports to salthelp@saao.ac.za