How can I look at a STIS spectrum with the HLA? How accurate is the wavelength scale?
With the 2-d spectral image displayed in the Interactive Display window, you can do both column (c) and line (l) plots. Place your cursor on the spectrum and hit the l key to make a line plot (you may want to expand the scale of the image to properly place your cursor on the spectrum). The plotting tool enables scaling, binning and smoothing, and to use various units. For slitted, first order observations, the wavelength scale should be good. However, for Echelle observations (which displays multiple orders in one image), the wavelength scale is not useful. Also, for STIS slitless observations (e.g., 50CCD/25MAMA aperture), the wavelength scale is only valid for those objects centered in the (direct) image (i.e., objects that would be centered if a slit were used).
