NICS - Omega Filters

"1mic" is a custom filter designed to cover the clear atmospheric region between the water absorption bands ending at 0.95 Ám and starting at 1.11 Ám, respectively. The flux for 0 magnitude star is about 5.2 10-6 erg cm-2 s-1 µm-1

The filter was manufactured by Omega and is mounted inside NICS tilted by about 3 degrees. Its transmission was measured directly inside the instrument by taking a series of spectra of a halogen lamp without and with the filter inserted before the AMICI and IJ dispersers. No significant (>10-4) out-of-band leak was found within the 0.8-2.6 Ám wavelength range.
The resulting transmission curves, measured at a temperature of about 78 K, is available in the following ASCII file.

Please keep in mind that the array efficiency may vary significantly with wavelength within the range covered by this filter.

WARNING! This filter is known to produce ghost images like those shown below. The brighter ghost contains about 0.4% of the star flux.

For any comments please contact Francesca Ghinassi.