Slit positions

I've gone through and adjusted the slit angles in the GUI for slits 1-6.  My IDL journal file for processing the data is in eE/analysis/cd38/slitimag/checkimages.jou

I started by doing slit images of slits 6 to 1 a total of three times to check for repeatability.  Other than the very first Slit 6 position, the slits were repeatable to +-1 pixel.  That's better than I expected.

I was using the N04679 filter in the Dekker wheel, so I checked how the slits compared to the long-slit position in the Dekker and decided we were biased a little to far positive in angles.  This also let me look at the number of pixels/degree.  The slit center of rotation seems to be at very large y values (>>1024).  Near the lower end of the slit (y = 300), I find a conversion of -0.0228 degrees/pixel.

Using the second pass through the slits, it looked like most of the slits were aligned to 4 pixels or so.  Slit 2 was pretty far off.  Even though these are small numbers, I made adjustments.  I also wanted to get slits a little better centered in Dekker slit.

Slit       Was         Now
1           59.7         59.473
2           90            89.522
3           119.57     119.388
4           149.5       149.341
5           179.75      179.454
6           209.57      209.32

After I edited EXES_wheelinits.txt to insert the new positions, I took another spin from Slit 6 to Slit 1 and looked at the results.  Defining the center of Slit 6 as good and going by eyeball cuts...

Slit       # pixels off from Slit 6
1          0
2          1
3          0
4         -2
5          0

Using the conversion factor above (-0.0228 degrees per pixel), I made a further adjustment to slit 4:
from 149.341 to 149.387 degrees in wheelinits.txt