The VDS detector
is mainly composed of a microchannel plate and a 1024x1024 pixels
charge coupled device (CCD), composed of four square sections.
The CCD was orientated with its columns parallel to the slit
alignment.
Therefore, any pixel Y position should represent a single Solar Y point,
while the grating dispersion is along the pixel X coordinates.
In reality, the CDS alignment is more complex, as shown in Figure 3.6.1
and described below.
A pixel in the detector Y direction corresponds to 1.68¢¢.
The extent in Y of the long slits (240¢¢) is therefore 143 pixels on the
detector.
A pixel in the dispersion (X) direction corresponds to about 0.07 Å for NIS 1
and 0.11 Å for NIS 2.
