DR2 Frequently Asked Questions

  1. Some of the spectra have "EB", "EC", or "WB" in their file names. What does this mean? The EB, EC, WB suffixes are tags that were added to the standard DEEP2 maskname (typically a digit #) by the Keck slitmask milling machine when those masks were made. Those masks had been milled previously but either were not observed (due to bad weather, etc.) or were observed under poor conditions, so we opted to reobserve the mask. For a subsequent observing run, the masks were remilled, rather than reusing the old masks, as dust on the mask can create funkiness in the slit function, thereby making the ends of the slits difficult to reduce cleanly. To distinguish duplicate copies of the same slitmask, the Keck milling process added an "A, B, C" to the end of the slitmasks name. This suffix was then put into the header of the raw DEIMOS frame and carried along through the DEEP2/DEIMOS pipeline. Yet another thing that I meant to clean up prior to the release, but time did not allow.

created by M. Cooper
last updated 2007feb11