Spectroscopy

Wavelength calibration lamps (Argon and Xenon) have been ordered and will be tried out in the lid on the Cassegrain baffle, where we expect the main problem to be low count rates, but preliminary tests with the Argon lamp have shown this not to be a problem. The flatfield lamp in the lid on top of the Cassegrain baffle has been proven to be useful for NOTcam, but the location is not optimal as at night the mirror cover need to be closed in order to make calibration exposures.

The problem with the focusing of the HR camera to be able to do higher resolution spectroscopy (R$\sim$6000) and other types of science that require aperture wheel items to be in focus on the detector, can be solved mechanically by machining the front off the aperture wheel unit and moving the aperture wheel unit by 2mm away from the collimator. Possibly, the lenses in the HR camera itself could be repositioned instead, but this should be looked at by an optical engineer. The latter option will most likely change the scale of the HR camera in imaging mode.

New holders have been made for the slits to be used with the WF camera, after experiments showed that the previous holders might play a role in the deformations of the slits when cold. The new holders are made of copper, which should have a similar expansion coefficient as the slits which are made of a thin copper/nickel laminate.

Further upgrades to the spectroscopic capabilities of NOTcam, e.g., R$\sim$6000 with the HR camera and R$\sim$800 with the WF camera, are still awaiting input from Nordic astronomical community regarding science drivers etc.