The picture above shows the line IDs for the H20 band near 1315 cm-1 in medium resolution mode.
I calculate a velocity per pixel of: 2.53 km/s/pix
I was forced to only use frames 1 and 2 of the SUTR data to avoid saturation.
And below is a table of the FWHM of the lines, which were calculated by fitting 5-parameter Gaussian functions across the 20 central-most rows of each line. The values below are the median(sigma*2.355) for the 20 fits across each line.
The line pair at 1313.5 and 1313.6 were partly blended, even with 1.5 km/s, so I didn't record their widths. Where other entries are missing, it is either due to blending, or to saturation.
#slit file 1 2 3 6 7 8
1.5 km/s b032 7.77 6.81 6.88 6.36 6.10 6.22
2.0 km/s b031 8.68 7.58 7.80 7.30 7.32
2.7 km/s b030 9.70 8.85 8.97 8.78
3.5 km/s b029 11.75 11.26 11.59 10.81
1.5 km/s b032 7.77 6.81 6.88 6.36 6.10 6.22
2.0 km/s b031 8.68 7.58 7.80 7.30 7.32
2.7 km/s b030 9.70 8.85 8.97 8.78
3.5 km/s b029 11.75 11.26 11.59 10.81
4.5 km/s b038 13.89 13.54
6.0 km/s b037 18.30
flux slit b036 6.0 km/s b037 18.30
For the mean values of FWHM, the resolutions are:
#slit mean(FWHM) v_res(km/s) R
1.5 km/s 6.69 16.9 17700
2.0 km/s 7.74 19.6 15300
2.7 km/s 9.08 23.0 13100
3.5 km/s 11.35 28.7 10400
4.5 km/s 13.72 34.7 8600
6.0 km/s 18.30 46.3 6500
Also, it seems clear that the right side is in better focus than the left. This was not clear to see in the high res modes. See the plot below.


1 comment:
Good to put in echelle angle and compare to theory here.
Echelle angle (alpha) = 53.46 according to echelle parameters.
Grating equation (using littrow and assuming theta = (alpha+beta)/2 or alpha+delta/2) says R = 2*tan(theta)/Delta_theta.
Delta_theta is slit width, which is nominally [98, 131, 175, 229, 294, 392] microns, divided by focal length, which is 1e6 microns.
Predictions are then that R~29,000; 21,600; 16,200; 12,400; 9600; and 7200.
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