VIRMOS Mask A typical VIMOS mask (quadrant 3 shown) with some 150 slits. Additional features are identified by letters as explained below.
[GIF: mask view]
a the starting point of the cutting of the contour is outside of the mask in order to have a clean outline
b the notches on the bottom are used to hold the mask inside the IC
c the two upper notches (in pink), a rectangular and a triangular-rounded one, are used by the reference pins in the instrument to ensure the final positioning of the mask during observations, they are cut separately as apertures with the CuttingFine tool to allow maximum accuracy and easy repositioning
d the three oval "manina" holes are used by the little hand device used to move the mask from IC to instrument
e the two rectangular fixing holes are used to hold the mask in position inside the instrument
f the 6-digit barcode used to identify the mask
g two curved slits are shown in this mask
h two square slits for reference objects are shown in this mask