ECH_PRISMPOS

Determine the optimal prism rotation and position

Description

Determine the prism rotation and position by direct calculation. The rotation is such that a ray of the specified wavelength will fall on the centre of the detector. The position is such that the echelle is fully illuminated by rays of the specified wavelength.

ECH_INIT must be called before calling this routine.

Invocation

CALLECH_PRISMPOS (WC, GAMMA, POS, STATUS)

Arguments
READ WC REAL

Desired central wavelength (Angstroms)

WRITE GAMMA REAL

Optimal prism rotation (radians)

WRITE POS REAL

Optimal prism position (mm)

READ, WRITE STATUS INTEGER

Global status value

Bugs

None known.

Authors

C.J. Hirst UCL (ZUVAD::CJH)