The BLACK-Comet UV-VIS spectrometers utilize a 40mm diameter concave grating with aberration correction to provide superb spectral imaging. This significantly improves spectral shapes by reducing comma and astigmatism found in plane grating spectrograph designs. The spectrograph architecture does not utilize mirrors, and therefore provides the lowest possible stray light in the UV with additional assistance from the holographic line grating. The concave grating produces a flat field on the CCD detector creating uniform resolution over the entire range.

One of the main advantages of the BLACK-Comet is its ability to drastically reduce straylight levels, 0.02% at 435 nm and 0.2% at 200 nm, the lowest values of any field spectrometer. By design, the holographic grating has a smoother surface than the normal ruled gratings used in competing spectrometer models. Surface roughness is the primary source of grating generated straylight and thus by employing superior grating technology, StellarNet’s Concave Grating Spectrometers are able to drastically reduce the effect. Additionally, grating scatter in the standard Czerny Turner design is collected and focused by the focusing mirror toward the exit port, this does not occur with the BLACK-Comet. When additional optical components like collimating and focusing mirrors are used in instrument design, it is more likely that light may be rediffracted and scattered. Similarly, due to the spectrometers ability to reduce light scatter, especially high power UV light, the Concave Grating spectrometer provides two to three times enhanced UV sensitivity as compared to plane grating/Czerny Turner optical configurations.

Specifications