CCD The basic reduction of data from electronic
detectors is done here. The data from the Ondrejov
observatory Reticon (acquisited by the local RETICON
program) are used directly, data from foreign instruments have to be
already one-dimensional and first converted to SPEFO format (see File
utilities). In both cases all types of files are requested --
*.OFF for offset (i.e. bias) data, *.FF for flat
field, *.CML for calibration light exposure and *.STA
for stellar spectrum. The specific point of using the Reticon
Ond submenu is following: Just the pixels 95-1790 (out of 1872)
are considered good and just one offset file is requested
Flat select First bias file is selected (for
foreign instrument several may be averaged), than one or more
flat field data (also may be averaged).
Derive disp Two comparison line exposures
(before and after the stellar exposure) are requested. Than the
comparison line list *.CMP for the same grating angle is
chosen. Than the line identification begins. The comparison lines
from particular *.CMP list are identified interactively in
either oscilloscopic or automatic mode with the chosen polynomial
fit order. The wavelength-zoomed comparison lines are displayed
and their approximate center position has to be marked by moving
of vertical line (see Fig. 1 ) together with their identification number
according to *.CMP list. Then the enlarged line together
with its mirror profile is shown that may be interactively
shifted until their exact match is reached (see Fig. 2). The
amount of the displayed mirrored profile may be changed
interactively too (see Fig. 1). After identification of at least
three lines the estimate of the dispersion curve fit is
calculated and the next lines may be identified automatically.
The badly defined line may be rejected. After the line list has been
exhausted, the dispersion curve is displayed with possibility of
the rejection of points with large errors. (See Fig. 3)
The protocol of comparison line measurement *.CMF
is finally produced.
Star reduce The stellar spectrum *.STA
file is chosen together with the corresponding *.OFF bias.
The result of the processing is the wavelength-calibrated
unrectified intensity file *.UUI.
