ITEM            general
ITEM_TITLE      NONE

	<p>The fluxes of all GIRAFFE calibration lamps are monitored here.
	 It is important to control the calibration lamp performance, both
	over and under exposure should be avoided. Over-exposure is an
	important issue for the flat-field lamps because the calibration files then
	are useless (at least for removing the pixel-to-pixel gain variations).
	Under-exposure for flat-field lamps results in compromised SNR,
	and for arc lamps in poor emission line detection and low-quality dispersion
	solution.<p>

	The calibration lamp fluxes are monitored through regular HC calibrations and deliver health check parameters.
	They are monitored to discover aging effects, 
	      filter degradation or problems with the gripper.</p>

	We monitor fluxes of two flat-field lamps and two arc lamps:
	      <ul>
	        <li>the <a href="#simlamp">arclamp</a> of the simultaneous calibration
	            unit: <br>used in operations only exceptionally (for high-precision wavelength
		calibration), simultaneously with the science exposure; 
		<br>used as daily health check to register
		the spectral format; </li>
	        <li>the <a href="#fflamp">flat field</a> lamp on the fibre positioner
	            calibration unit (&quot;robotic flat&quot;):
		<br> used in operations as standard lamp
		for flat-field exposures, taken as daytime calibration;</li>
	        <li>the <a href="#nasmyth">nasmyth lamp</a> (&quot;nasmyth flat&quot;):
		<br>used for the IFU modes as night or twilight calibration since they provide a better illumination across the FOV.
		</li>
	        <li>the <a href="#arclamp">arc lamp</a> on the fibre positioner calibration
	            unit:
		<br> used in operations as standard wavelength calibration, taken as daytime
		calibration;
		</li>
	      </ul>