TSX: Calibration Files

• tsx_edge.dat : These are polynomials which define the edges of the echelle order slits. Ten polynomial coeffecients are included in this file (top and bottom of each echelle order 3,4,5,6,7). The first line for a given echelle order is the lower bound (if echelle order 3 is at the top of the image), and the second line is the upper bound. The first number is the echelle order, the 2nd number is a 'x offset' value, the 3rd - 5th numbers are the 3 coeffecients of a second order polynomial. So, at a given column, the row value for echelle order 3 would be given by:

     row = coef[0] + coef[1]*x + coef[2]*x*x,   where x = column - 'x offset'.
  

  futhermore, the lower bound of each echelle order is offset (except echelle order 3) by the following values: 1.62, 3.54, 4.61, and 5.68 for echelle orders 4,5,6,7. This is done to align each echelle order so that an object in the slit appears at the same position (relative to the lower bound) for all echelle orders. (The slit of each echelle order covers a different portion of the sky.)

• flatimg.fits : A normalize flat field image taken by summing up several individual flat field exposures from a night in 2013. The summed flat field image was divided by a smoothed version of the same flat field image. This perserves the pixel-to-pixel variations but not the large scale variations. The regions outside of the echelle orders are ignored.

• maskimg.fits : An image showing the position of high and low pixels to be replaced by interpolated pixels. Image pixels which are 0.0 in 'maskimg.fits' are good pixels. Pixels >0 are hot pixels, pixels <0 are low pixels. The high pixels are also given in 'maskhigh_pixels.tbl' and the low pixels are in 'masklow_pixels.tbl'. The file 'maskhigh_pixels.ps' and 'masklow_pixels.ps' show histograms of the high and low pixels.

• toff.poly : These polynomials are used to convert pixels to arcseconds for each echelle order. The first polynomial yields the arcsconds vs. row offset from lower bound of echelle order for order number 3. The following polynomials give the pixel offset foe each row in the following echelle orders.

• tsns#.dat : These are ASCII tables of night sky line identifications. One table for each echelle order. The first column is the column number (centroid) and the second column is the vacuum wavelength of each OH emission line. Note that the 'column' number is really the inverse column (blue to red) since the spectra are flipped relative to the raw image in the final extraction. Also see the files 'skylines#.tbl' which shows both the raw and inverse column numbers. (See "Night-sky spectral atlas of OH emission lines in the near-infrared" by Rousselot et al., Astronomy and Astrophysics 1999.) These files are read in for each reduction and 3rd order polynomials are fit to each echelle order.

• TYC.bin : Binary version of Tycho catalog (used to compute effective temperatures of bright (telluric) stars using B-V). Each entry in binary file is a C structure:

  struct TYCstructure {
    double mean_ra,mean_dec;
    float bt_mag,vt_mag;
    float bt_mag_error,vt_mag_error;
  };
  typedef struct TYCstructure TYCtype;
  

• VegaCal.tbl : Calibrated spectrum of Vega, used to correct intrinsic absorption lines in vega-like stars.

• vega_abs.dat : List of infrared absorption regions (in Angstroms) in Vega spectrum which are corrected in vega-like stars.