Plot ? 
Symb ? 
Source * 
Average ? 
Thresholds ? 
N_ data 
QC1 parameter 
Data downloads 
Remarks 
method 
value 
unit 
method 
value 
1 
•  QC1DB 
MEDIAN 
8.36625 
pix/mm 
VAL  8.361,8.370 
68 
xx 
this 
last_yr 
all

coefficient a(xx), Q2 
2 
•  QC1DB 
MEDIAN 
8.38476 
pix/mm 
VAL  8.380,8.389 
67 
xx 
this 
last_yr 
all

coefficient a(xx), Q1 
3 
•  QC1DB 
MEDIAN 
8.36531 
pix/mm 
VAL  8.360,8.369 
68 
yy 
this 
last_yr 
all

coefficient a(yy), Q2 
4 
•  QC1DB 
MEDIAN 
8.3841 
pix/mm 
VAL  8.379,8.388 
67 
yy 
this 
last_yr 
all

coefficient a(yy), Q1 
5 
•  QC1DB 
MEDIAN 
8.39485 
pix/mm 
VAL  8.389,8.398 
68 
xx 
this 
last_yr 
all

coefficient a(xx), Q3 
6 
•  QC1DB 
MEDIAN 
8.39311 
pix/mm 
VAL  8.388,8.397 
68 
xx 
this 
last_yr 
all

coefficient a(xx), Q4 
7 
•  QC1DB 
MEDIAN 
8.39308 
pix/mm 
VAL  8.387,8.396 
68 
yy 
this 
last_yr 
all

coefficient a(yy), Q3 
8 
•  QC1DB 
MEDIAN 
8.39188 
pix/mm 
VAL  8.387,8.396 
68 
yy 
this 
last_yr 
all

coefficient a(yy), Q4 

*Data sources: QC1DB: QC1 database; LOCAL: local text file

This plot
Trending plots for monitoring the coefficients of the mask to CCD transformation.
The transformation is as follows:
X = a(xx)*x + a(xy)*y + x(0)
Y = a(yx)*x + a(yy)*y + y(0)
with (x,y) being mask coordinates in mm and (X,Y) CCD coordinates in pixel.
X direction is along the slit orientation, y direction is perpendicular to
the slits (i.e. in dispersion direction).
These trending plots show the time
evolution of the matrix coefficients a(xx), a(xy), a(yx), and a(yy). The
diagonal coefficients a(xx) and a(yy) give the scale factor between mask and
CCD (near 8.4 pixel/mm). Variations are mainly cause by temperature changes,
the empirical tolerance is around +/ 0.006 pixel/mm.
The coefficients a(xy) and a(yx) give the rotation and should be near zero.
The tolerance is +/ 0.005 pixel/mm around the empirical average.
The procedure in case of violation of the thresholds is described on the
SciOps Wiki pages.
Template ID: img_tec_MaskToCcd. Pipeline recipe: vmmasktoccd.
General information
Click on any of the plots to see a closeup version.
The latest date is indicated on top of the plot, data points belonging to that date are specially marked.
If configured,
 statistical averages are indicated by a solid line, and thresholds by broken lines
 outliers are marked by a red asterisk. They are defined as data points outside the
threshold lines
 "aliens" (= data points outside the plot Y limits) are marked by a red arrow (↑ or ↓)
 you can download the data for each parameter set if the 'Data downloads' link shows up
