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Astrodon Photometrics Sloan Gen2 Y Filter - 950/1058 nm - 1.25" Threaded Cell - Y2-27R

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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

Sloan Digital Sky Survey (SDSS) filters are made to cover the electromagnetic spectrum from 300 nm to the silicon CCD camera sensity limit of approximately 1100 nm. Non-overlapping for the most part, these five filters blend colored glass filters with short-pass dielectric coatings to make the low wavelength side of the bandpass more steep. The 557.7 nm sky glow line appears between the G and R filters and is therefore minimized.

The most popular filter set in current use, the SDSS photometric filter system is employed by the Hubble Space Telescope to enable a large research reference database. A significant portion of photometry up to magnitude 23 will be completed in this system using meter-class telescopes. SDSS filters will also be used by such large collaborative survey projects as the Large Synoptic Survey Telescope (LSST) and the Panoramic Survey Telescope and Rapid Response System (Pan-Starrs).

These Astrodon Generation 2 Sloan Filters have progressed beyond the previous generation via technical input from Las Cumbres Observatory Global Telescope Network (LCOGT) among others. Atmospheric skyglow is better eluded due to extra separation included between the G and R filters. The Y and Z-S near-infrared filters were added specifically to ensure that the filter controlled the high wavelength cut-off instead of the detector. This contrasts with Astrodon's Z filter, which is a simple cut-on, or long-pass filter. Finally, out-of-band blocking has been tightened from average to exact specification to further reduce the already minimal leakage.

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 NIR "Y" Filter

1.25" round mounted Sloan Gen2 Y Filter with 100% coatings to allow lasting durability and consistency for long-term research projects. Designed from a single high quality fused silica substrate 3 mm in thickness using no colored glass, this Astrodon filter features the highest throughput possible. The Astrodon photometrics Sloan filter family added this near-infrared (950 nm to 1058 nm) Y filter in order to ensure that the filter controls the high wavelength cut-off and not the detector.

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