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Standard types of List

As mentioned previously LEXT has a variety of uses for list data. Different functions may operate with only certain lists so in order to differentiate between them lists are designated one of the following :

• BOXES defines rectangular regions of the image which are used to designate the positions and extent of each of the spectra within the 2D image. (All in pixels).

  (X-start, Y-start, X-end, Y-end, ID, Y-pos object, Y-extent obj, X-pos zero-order)

• KNOTS defines the fiducial points for the spline.

  (X-value, Y-value)

• MASK defines the mask details.

  (ID, Obj X (mm), Obj Y (mm), Slitlen, Slitoffset, Obj app RA (rad), Obj app dec (rad), Weight)

  Note that zero weight conventionally designates a Wood's hole.

• POS holds object positions and magnitudes. This is only for user information, rather than processing. It has no official column headers, but, if it is to be output by FPRINT then the following are assumed:

  (CosX, CosY, ID, B, R, B-R )

• ARCL holds standard arc-line wavelengths.

  (Lambda (Å))

• CLIST object positions in pixel units. May also be any list of points.

  (X-pos, Y-pos, Height, X-sig, Y-sig, Background )

• MLIST object positions in mm units at the focal plane.

  (As CLIST)

• FIBOX defines the extent and positions of rectangular regions for use with FIT. (All in pixels).

  (Xcen (pix), Ycen (pix), X-extent, Y-extent)

• LIPOS stores line positions identified for each arc spectrum.

  (X (pix), Lambda (Å), Box num)

• COEFS contains linearity correction for SCRUNCH, for each arc spectrum.

  (Npt fitted, Coef , Coef , Coef , Coef , Coef , Coef , Coef )

• RESL contains the full details of the fit to the arc lines in a given spectrum.
• YPROF profile of pixel values in Y direction.

  (Y-val, Summed int)

• XPROF profile of pixel values in X direction.

  (X-pix, Flux, Lambda(Å))

• OPROF profile of object spectrum, not scrunched.

  (X-pix, Flux, Lambda(Å))

• WPROF profile of weighted spectrum, not scrunched.

  (X-pix, Flux, Lambda(Å))

• SPROF profile of sky spectrum, not scrunched.

  (X-pix, Flux, Lambda(Å))

• SPEC contains a 1D spectrum as a function of wavelength.

  (Lambda(Å), Flux)

• OSPEC scrunched object spectrum.

  (Lambda(Å), Flux)

• WSPEC scrunched weighted spectrum.

  (Lambda(Å), Flux)

• SSPEC scrunched sky spectrum.

  (Lambda(Å), Flux)

• FSPEC contains fluxing standard.

  (Lambda(Å), Response)

• DRCT contains a boxes file, created by PREDIRECT for a direct image.

• RESL keeps details of the scrunch fit to the arc lines for an individual box.

• FITL list contains details from auto-refine during automatic arc fitting.

• DLIST distorted list

The designated of a list can be modified at any time by means of the RETYPE command. This is useful to change the semantic interpretation of the list data. LEXT will even allow an invented , which may, of course, make sense if the user wants to store any unusual information, but could not be interpreted automatically by LEXT.