Hamilton Thorium-Argon Spectrum

  • The overexposed Argon lines at the top of the image are a necessary evil of the Th-Ar lamp. They may be partly suppressed by using a bg38 filter, but at the cost of also suppressing useful lines in the red.
  • Note that the image is shown here as it appears in the data-taker's image display, with the row-column origin (0,0) at upper left. Many displays programs put the origin at lower left.
  • The dark vertical strip on the right is the CCD's overscan region.
  • m = order number
  • Only order numbers are given here. For wavelengths of individual lines, refer to Lick Observatory Technical Report #73, The Hamilton Spectrograph TH-AR Atlas by M. D. Shetrone (it's a green, paperbound book, copies of which should be floating around in the 3-m and CAT control rooms). The UCB astronomy department has also upublished an on-line, Hamilton-specific, Thorium-Argon atlas.