UVES pipeline:
order trace table

The order trace table is created by the UVES pipeline in the optimal extraction mode. It contains, order by order (in order-bin space), the following parameters as calculated in the course of the extraction process:

column name	parameter	content
ORDER	order number	counting from 1 to N where N is the maximum number
I_CH	index of chunk	for each order, parameters are evaluated at certain X positions (chunk; typically 50-100)
X_CH_0	X position of chunk	X position in px

P_CH	Y position of signal in chunk	measured Y position of the maximum in the signal as found by the optimum extraction routine
P_ERR0	variance of Y position	error related to P_CH
P_F0	Y position of signal after first fit	A 2nd order polynomial is fitted to the P_CH values where all values with an error above a threshold (2 sigma rms) are excluded.
P_F1	Y position of signal after second fit	A kappa-sigma routine is used to clean the positions P_CH from outliers with high weight factors (low P_ERR0 but outlier in P_CH). Then a final 2nd order polynomial fit is performed. The :P_F1 values are then used to extract the signal.
M_0	mask value (0 or 1)	mask value before first fit (1 is good)
M_1	mask value (0 or 1)	mask value before last fit (1 is good)

P_FWHM	cross-dispersion width of signal	measured cross-dispersion width per chunk (these values are obtained by fitting a Gaussian to the signal profile but they are measured in the sense that they are independent of each other)
P_FWHM_ERR	variance of FWHM	error related to P_FWHM
S_CH_0	width of signal after first fit	A 2nd order polynomial is fitted to the P_FWHM values where all values with an error above a threshold (2 sigma rms) are excluded.
S_CH_1	width of signal after final fit	A kappa-sigma routine is used to clean the FWHM values from outliers with high weight factors (small errors).

BKGVAL	background value of fit	background value (linear offset) used to obtain the fit; this number contains any contribution to the background like sky, scattered light, extended emission. It is usually dominated by sky emission, especially in case of moon light background. BIAS is not included here (it has been removed prior).
BKGERR	error of BKGVAL	associated error

UVES pipeline: order trace table

UVES pipeline:
order trace table