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MMTO F/9 Top Box Comparison Lamp Spectra


The f/9 topbox has a variety of comparison lamps observers may use to calibrate their spectroscopic data.  The following lamps are available without any special preparation:

  • Fe-Ne (hollow cathode)
  • He-Ar (AC glow discharge)
  • Neon (low pressure discharge)
  • Hg-Cd - attenuated longward of 4000 Å with a U-330 filter.
  • Incandescent (`Bright' and `Dim')
  • `Dome' Incandescent lamps
  • Etalon - several spacings are available.

Note that these lamps can be on simultaneously for added flexibility. There is also the option for observers to use a ThAr lamp, but they must notify observatory staff well in advance of their run as these lamps are mounted in place of the standard HeAr lamps (so both cannot be used during the same run).   

Below are spectra of MMT HeNeAr lamps with wavelengths of the prominent lines marked. The linelist used is available hereAll indicated wavelengths are in air.

In all but the Echellette spectra, the normalization shows the counts per second per pixel on the CCD after bias subtraction, but no gain or flat field corrections have been applied.  Note that the binning used is either 1x1 or binned by 2 in the spatial direction (1x2 for blue channel, 2x1 for red channel);  the binning used is shown in the title of each plot.  Please contact Joannah Hinz if you require more information or have questions.

Blue Channel:

 300 gpm : 

500 gpm :

600 gpm (2nd order):

800 gpm:
832 gpm (1st order):
832 gpm (2nd order):
1200 gpm:

270 gpm : 

300 gpm : 

600 gpm (4800 center): 

600 gpm (6310 center): 

1200 gpm (5767 center) : 

1200 gpm (7700 center)



Red Channel Echellette:

These plots show the spectra of the He-Ar + Ne lamp taken with 150 gpm Red Channel echellette grating set such that its blaze was near the middle of the chip. The spectral resolution is about 90 km/sec. Spectra of the individual orders are presented along with a combined spectrum plotted at both medium and large scale. Note that the data are not flux calibrated so that the relative line strengths are not accurate.

Red Channel Echellette -- Individual Orders

Red Channel Echellette -- Combined, Medium Scale

Red Channel Echellette -- Combined, Large Scale