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Astrodon Photometrics Sloan Gen2 Z Filter - >826 nm - 1.25" Threaded Cell - Z2-27R
About Astrodon Gen2 Sloan Filters
Astrodon filters are high performing, durable filters that provide significant aid for astrophotography and research pursuits. Each filter is constructed using a highly innovative process with a single high quality 3 mm thick fused silica substrate and full hard oxide sputtered coatings. Optimally equipped to provide consistency for long-term research undertakings, Astrodon Sloan Photometric filters are fully coated without colored glass. Featuring the highest throughputs on the market, these filters are able to improve signals and enhance faint night sky objects.
Astrodon Gen2 Sloan Photometric Filters - Additional Information
These Sloan Digital Sky Survey (SDSS) filters, as initially conceived, included five mostly non-overlapping filters that cover a spectral range from 300 nm up to the silicon CCD camera sensitivity limit of approximately 1100 nm. They steepen the low wavelength side of the bandpass via a combination of colored glass and short-pass dielectric coatings. As it occurs between the G and R filters, the 557.7 nm skyglow line is thus diminished.The most common filter system in current use, SDSS photometric filter sets are even used by the Hubble Space Telescope to provide a large reference database for research. This system in conjunction with meter-class telescopes will accomplish much of photometry up to magnitude 23. Upcoming large collaborative survey projects such as the Large Synoptic Survey Telescope - LSST, and Panoramic Survey Telescope and Rapid Response System - Pan-Starrs, will also employ the SDSS filter system. Using technical contributions from Las Cumbres Observatory Global Telescope Network (LCOGT) among others, Astrodon has taken their Photometric Sloan Filters to the next level. With these Generation 2 Filters, more separation is included between the "G" and "R" filters for greater avoidance of atmospheric skyglow. This Astrodon "Z" filter is a cut-on or long-pass filter. Finally, leakage already at a minimum is further reduced by tightened out-of-band blocking form average to absolute specification.
Astrodon Gen2 Sloan Filter Highlights
- Provides 50% transmission points (+/- 3 nm typical)
- Maximum transmission assured over 95%
- At most 0.03% tabs out-of-band from 300 nm to 1100 nm
- Single striae-free fused silica substrate
- 1/4-wave propagated wavefront prior to coating
- <0.5 arcminute substrate parallelism
- Substrate thickness is 3 mm +/- 0.025 mm before coating
- Proudly manufactured in the USA
Astrodon 1.25" Gen2 Sloan Long-Pass "Z" Filter
Edge-blackened 1.25" round mounted Astrodon Generation 2 Sloan Near-Infrared "Z" Filter with the highest possible throughput available. This cut-on, or long-pass filter, transmits light above 826 nm. Features 100% coatings for the consistency and reliability needed for extended research projects. Like all Astrodon filters, this Sloan photometric filter was made using a single high quality 3 mm thick fused silica substrate without colored glass.
Astrodon Sloan Gen2 Filter Detailed Specifications
- 3 mm +/- 0.025 mm fused silica substrate
- 25.4 mm +/- 0.1 mm diameter filter size
- Central 23.4 mm diameter minimum clear aperture
- TWF: <= 1/4 lambda per any 25mm square area before coating
- Coating to edge of part
- AOI: 0º
- Scratches: <= 0.06mm width; no limit on length
- Particles/Bubbles: <= 0.4 mm diameter
- Pinholes/Voids: <= 0.2 mm diameter
- Edge finish as fabricated
- Chips: <= 0.5 mm
- Edge Treatment: Edge-blackened with Enthone M-0-N black epoxy ink
- Thickness: <= 0.1 mm which may extend 0.5 mm onto top and bottom surfaces