# smile setting?

Forums Spectroscopy I’m doing something wrong smile setting?

#577721
Participant

Hi Kate,

What smile settings have you used?  If you do not have a calibration module, you can measure the smile using sky lines.  I tried your images assuming vertical lines with no smile (by setting the Y smile to the same as the spectrum position and the radius to a large number eg 999999) and got an RMS of 1.14 A using a pixel size of 4.68um

————————————————————————–

Wavelength fit deviation

point #1  x = 704.340  lambda = 3834.491  dlambda = 0.899

point #2  x = 725.984  lambda = 3889.299  dlambda = -0.249

point #3  x = 758.121  lambda = 3970.993  dlambda = -0.913

point #4  x = 809.533  lambda = 4102.375  dlambda = -0.625

point #5  x = 901.554  lambda = 4339.253  dlambda = 1.227

point #6  x = 1102.840  lambda = 4861.706  dlambda = -0.366

point #7  x = 1771.045  lambda = 6562.745  dlambda = 0.065

point #8  x = 1898.937  lambda = 6872.037  dlambda = -0.037

————————————————————————–

Coefficient a4 : 3.006774E-11

Coefficient a3 : -2.735230E-07

Coefficient a2 : 6.837095E-04

Coefficient a1 : 1.92972

Coefficient a0 : 2221.769

————————————————————————–

RMS : 1.116470

————————————————————————–

In his ALPY tutorial, Christian Buil suggests an RMS of 2-3 A maximum is acceptable for this calibration method

Cheers

Robin