| parameter | description | default |
|---|---|---|
| image | Image name for blue or red side data | "" |
| input | input file that contains box locations (box coordinate file) | "" |
| new_x_fwhm | [Enter new x FWHM] | 4 |
| new_y_fwhm | [Enter new y FWHM] | 4 |
| vmag | [magnification factor] | 100 |
| wt | [weight] | 1 |
| pairs | name of a coordinate file (not used unless the PA is so far off that only one alignment star falls in an alignment box)
|
"" |
| nxbox | size of the extraction box in the x direction | 50 |
| nybox | size of the extraction box in the y direction | 50 |
| xsz | x box length (pixels) | 30, 19 |
| ysz | y box height (pixels) | 30, 19 |
| fwhm | star FWHM in x (pixels @ .135''/pix blue side) (pixels @ .21''/pix red side) | 6, 4 |
| xoff | add'n. x shift to apply (pix) | -204, 0 |
| yoff | add'n. y shift to apply (pix) | 0 |
| xgap | edge between chips (blue side only) | 2252 |
| def_ref_err | default error estimate | 0.2 |
| def_err | default error estimate | 0.2 |
| niter | number of iterations in fit | 6 |
| box_size | box half-len (usually acceptable resid) | 0.5 |
| coord | graphics cursor input | "" |
lbox locate boxes on LRIS slitmasks and measures centroids of stars within them. The centroids are used to solve for the instrument rotation and telescope translation required to move the stars to the box centers. This program is a combination of two previous tasks, mboxfind and maskalign.
If check_boxes was not used to launch lbox , start lbox by typing
lbox image coordfilewhere image is the name of the FITS image you took, and coordfile is the name of a file containing the coordinates of the guidestar boxes.
When lanched, the routines graph marginal cuts of each box, showing the box location, and if the alignment stars were imaged through the box, the centroid of the star. At this point, you need to check the centering of the software. The following key commands are used to check the centering:
| q | accept and move to the next box (a quality fit). "quit" the current image display. |
| i | ignore and move to the next box |
| f | mark the center of the star at the x location of the current cursor position. "f" Forces an object center at the cursor position. |
| spacebar | set the back ground level at the y location of the current cursor position |
| r | redraw the plot. |
| w | enter a new FWHM for star |
| I | Interrupt the task immediately (abort) and return to the command prompt. |
| ? | print the list of tasks |
Normal procedure if a box looks OK type "q". Below is an image displaying typical output for a star well centered in an alignment box. The verticle solid line is indicates the determined center of a guassian fit to the stellar profile. The dashed line indicates the determined sky level. The box at the bottom, describes the region where the softwared defined the alignmet box.
| q | accept the residual plot and "quit" the graphic display. |
| c | change weight of nearest point (use for undelete) |
| m | change magnification factor of residual vectors |
| f | refit the residuals and replot |
| I | Interrupt the task immediately (abort) and return to the command prompt. |
| ? | print the list of tasks |
The program will report the suggested moves in rotation and position, as well as the uncertainties (in parenthesis).
[CONFIRM] Send DCS commands? (y/n) [y]:and then procede with rotator moves and x and y moves if necessary.