• Resolution                    R = 60 000
• Wavelength range        350 nm < lambda < 820nm
• Detector                       2Kx2K, 15 micron pixel size
• Readout                       40/80 s in fast/slow mode
• Fiber,                           4.6 m length
• Fiber on the sky            1.3 arcsec

  The total transmission of the spectrograph including the telescope has been
  computed and verified for most of the parts. Assuming a well functioning telescope
  the result is shown in percent in the following figure

                                            

  Figure 1.     Total transmission over the wavelength range, varying between 5% to 10%. This is
  the design values. This is based on Aluminium coatings on the collimators, but actually the
  mirrors were delivered with silver coating. This means the peak transmission is higher, but
  in the UV a steep fallof takes place around 400 nm.

  The spectral format consists of 90 spectral orders, widely spaced in the blue
  end of the spectrum and closer in the red end. Fig. 2 shows the layout on a
  30 mm square CCD chip. The free spectral range (FSR) varies from 22Å
  to 119Å at long wavelengths.

               

  Figure 2. The spectral orders of FIES as imaged onto a 30 by 30 mm CCD chip.

 Order   Central      FSR        Low        High  (micron)

   69     0.8209     0.0119     0.8149     0.8268
   70     0.8092     0.0116     0.8034     0.8149
   71     0.7978     0.0112     0.7921     0.8034
   72     0.7867     0.0109     0.7812     0.7921
   73     0.7759     0.0106     0.7706     0.7812
   74     0.7654     0.0103     0.7603     0.7706
   75     0.7552     0.0101     0.7502     0.7603
   76     0.7453     0.0098     0.7404     0.7502
   77     0.7356     0.0096     0.7308     0.7404
   78     0.7262     0.0093     0.7215     0.7308
   79     0.7170     0.0091     0.7124     0.7215
   80     0.7080     0.0089     0.7036     0.7124
   81     0.6993     0.0086     0.6950     0.7036
   82     0.6907     0.0084     0.6865     0.6950
   83     0.6824     0.0082     0.6783     0.6865
   84     0.6743     0.0080     0.6703     0.6783
   85     0.6664     0.0078     0.6624     0.6703
   86     0.6586     0.0077     0.6548     0.6625
   87     0.6511     0.0075     0.6473     0.6548
   88     0.6437     0.0073     0.6400     0.6473
   89     0.6364     0.0072     0.6328     0.6400
   90     0.6293     0.0070     0.6259     0.6328
   91     0.6224     0.0068     0.6190     0.6259
   92     0.6157     0.0067     0.6123     0.6190
   93     0.6090     0.0065     0.6058     0.6123
   94     0.6026     0.0064     0.5994     0.6058
   95     0.5962     0.0063     0.5931     0.5994
   96     0.5900     0.0061     0.5869     0.5931
   97     0.5839     0.0060     0.5809     0.5869
   98     0.5780     0.0059     0.5750     0.5809
   99     0.5721     0.0058     0.5692     0.5750
  100     0.5664     0.0057     0.5636     0.5692
  101     0.5608     0.0056     0.5580     0.5636
  102     0.5553     0.0054     0.5526     0.5580
  103     0.5499     0.0053     0.5472     0.5526
  104     0.5446     0.0052     0.5420     0.5472
  105     0.5394     0.0051     0.5369     0.5420
  106     0.5344     0.0050     0.5318     0.5369
  107     0.5294     0.0049     0.5269     0.5318
  108     0.5245     0.0049     0.5220     0.5269
  109     0.5196     0.0048     0.5173     0.5220
  110     0.5149     0.0047     0.5126     0.5173
  111     0.5103     0.0046     0.5080     0.5126
  112     0.5057     0.0045     0.5035     0.5080
  113     0.5013     0.0044     0.4990     0.5035
  114     0.4969     0.0044     0.4947     0.4990
  115     0.4925     0.0043     0.4904     0.4947
  116     0.4883     0.0042     0.4862     0.4904
  117     0.4841     0.0041     0.4820     0.4862
  118     0.4800     0.0041     0.4780     0.4820
  119     0.4760     0.0040     0.4740     0.4780
  120     0.4720     0.0039     0.4700     0.4740
  121     0.4681     0.0039     0.4662     0.4700
  122     0.4643     0.0038     0.4624     0.4662
  123     0.4605     0.0037     0.4586     0.4624
  124     0.4568     0.0037     0.4549     0.4586
  125     0.4531     0.0036     0.4513     0.4549
  126     0.4495     0.0036     0.4478     0.4513
  127     0.4460     0.0035     0.4442     0.4478
  128     0.4425     0.0035     0.4408     0.4442
  129     0.4391     0.0034     0.4374     0.4408
  130     0.4357     0.0034     0.4340     0.4374
  131     0.4324     0.0033     0.4307     0.4340
  132     0.4291     0.0033     0.4275     0.4307
  133     0.4259     0.0032     0.4243     0.4275
  134     0.4227     0.0032     0.4211     0.4243
  135     0.4196     0.0031     0.4180     0.4211
  136     0.4165     0.0031     0.4149     0.4180
  137     0.4134     0.0030     0.4119     0.4149
  138     0.4104     0.0030     0.4090     0.4119
  139     0.4075     0.0029     0.4060     0.4090
  140     0.4046     0.0029     0.4031     0.4060
  141     0.4017     0.0028     0.4003     0.4031
  142     0.3989     0.0028     0.3975     0.4003
  143     0.3961     0.0028     0.3947     0.3975
  144     0.3933     0.0027     0.3920     0.3947
  145     0.3906     0.0027     0.3893     0.3920
  146     0.3880     0.0027     0.3866     0.3893
  147     0.3853     0.0026     0.3840     0.3866
  148     0.3827     0.0026     0.3814     0.3840
  149     0.3801     0.0026     0.3789     0.3814
  150     0.3776     0.0025     0.3764     0.3789
  151     0.3751     0.0025     0.3739     0.3764
  152     0.3726     0.0025     0.3714     0.3739
  153     0.3702     0.0024     0.3690     0.3714
  154     0.3678     0.0024     0.3666     0.3690
  155     0.3654     0.0024     0.3642     0.3666
  156     0.3631     0.0023     0.3619     0.3642
  157     0.3608     0.0023     0.3596     0.3619
  158     0.3585     0.0023     0.3574     0.3596
  159     0.3562     0.0022     0.3551     0.3574