Swope e2v Reductions

Swope at night
Photo by Yuri Beletsky, Las Campanas Observatory

Our Magellanic Cloud WR Survey is using the new Swope e2v camera.

The IRAF scripts e2v14.cl (2014) and e2v.cl (2015+) that will automatically reduce a night's of data assuming that you have bias frames and flat-field exposures (sky flats are preferred) all in the same directly. To run it, you must first load imred and ccdred, and do a "setinstrument direct". The program will mosaic the four quadrants together and leave you with 4110x4096 images transposed such that N is up and E is to the left.

Here's what is under the hood, and why.

IRAF is very header-driven, and unfortunatley some of the e2v header details are not consistent with what IRAF expects. Some particular problems are:

  • The first two columns of each quadrant are actually wrap-arounds from the ovverscan at the end. Thus, the true trim and bias sections differ from what is in the header. Furthermore, this means that the DATASEC is incorrect, and will mess up any reduction efforts.

    Here is our full procedure: