Ground Based Astronomy

Ground Based Astronomy Applications

Filters and coatings are critical components of almost all ground based astronomical instrumentation. Since its inception Barr has supported this community without break - forty years. Our filters can be found on most of the ground based telescopes throughout the world including Gemini Observatory, Southern African Large Telescope (SALT), Keck Observatory (MOSFIRE instrument), National Astronomical Observatory of Japan (Subaru camera), University of Hawaii Institute for Astronomy (PanStarrs camera), European Southern Observatory (supporting VLT and LaSilla)

Key Applications:

Imagers

Filters are used in imagers as wavelength discriminators. With the advent of very large, wide field telescopes and large detector arrays, the filter size requirements have tracked that size growth. Presently many application require filters of several hundred millimeters diameter. These must exhibit the same performance characteristics over the full filter surface. We have been extremely successful in meeting these demanding requirements.

Spectrometers

Although usually not the primary wavelength discriminating device in spectrometers, filters do play a critical role. In the case of grating based instruments they provide an order-sorting function. For Fabry-Perot instruments they separate the wavelength of interest from a series of closely spaced FP passbands. These filters are often the narrowest that can be produced as multilayer interference filters. Requirements for FWHM bandwidths at 0.05% of wavelength-of-interest are not unusual.

Beam Handling

Beamsplitters and high performance mirrors are important elements of any optical system. Barr produces these at very high performance levels. Antireflection coatings on delicate optics are a specialty. We can coat CaF2 and other crystals in sizes up to 500 mm. We also coat metal (Al and Be for example) and composite substrates with enhanced, durable broadband mirrors.

Products & Services

Optical Filter Products

Bandpass and Edge Filter UV through LWIR
Dichroic Beamsplitter
High Efficiency Reflector
Single and multi notch filter
Rugate Filter

Non-optical Products

Custom metallizations