REVISION DATE: 14-Mar-2018 14:21:08

Comparing the pen lamp wavelength cals and wavelength cals done using fraunhofer lines. Not too bad. As you might predicted the fit is better in the middle where the fraunhofer lines exist and worse on the blue end where there are fewer lines.

I did the Fraun line wavecal 2 ways. One way (old) I used only 6 lines, the two blue-est lines where left out. The second way uses 8 lines which is the way I do the cal for the in-water data. Interesting that adding more lines does a worse job. They all use a 2nd order polynomial fit.

When discussing this with Ken he mentioned the wavelengths I was using for the fraun lines may be a bit off which is why the 2 UV lines make the fit worse. So he asked me to change the 382 nm line to 383.3 and see if that helped.

Kens email: Wonder what would happen if you changed the line that you said was 382 to 383.3. This is the from high res spectra from Modtran (so includes all atmospheric lines) which I convolved with a 1nm gaussian bandpass to match MOBY/refresh roughly...

The new wavelength seems to improve the data quite a bit. Ken is going to do the same for my other lines to see if that helps. The Fraun8-allnew is the fit after Ken sent me all the new lines. We are getting there

March 2018 Mike suggested I add the 358 and 396 lines which I did. Results are below

Fraun line wavelengths and fitted pixel positions
-------------------------------------------------------------------------------------
 Fraun       Fitted Pixel    Fraun                            Fraun                  
 Wave        Location        Waves for new fits               2 more lams, fix 2                
-------------------------------------------------------------------------------------
    358.121  53.31                                            358.37      10 fraun-allnew
    396.847  127.19                                           396.83      10 fraun-allnew
    382*     127.20305      383.3 fraun8-1new fraun8-allnew   383.33      10 fraun-allnew(fixed 2nd digit)
  393.4*     157.19328      393.35 fraun8-allnew
  430.7      266.00642      430.54 fraun8-allnew
  486.1      426.68062      486.13 fraun8-allnew
  517.2      514.65085      516.97 fraun8-allnew              516.98      10 fraun-allnew (fixed 2nd digit)
    589      719.71997      589.24 fraun8-allnew
  656.3      908.09067      656.28 fraun8-allnew
    687      994.47247      687.18 fraun8-allnew
--------------------------
*not included in 6 fraun line fits

Comparison of two ways to do wavecals.

Figure 1