Astrodon

These research filters were replaced in June, 2012 with our Generation 2 Sloan filters (click here). 

We are therefore offering our Gen 1 filters at close-out prices while quantities last. Only direct from Astrodon. 

The main differences are discussed  on the Gen 2 Sloan page.  Briefly,

1. Different 50%T points for the i' and r' filters
2. Introducing the z_s and Y near-infrared filters that together replace the z' cuton filter
3. Retaining the z' filter for those preferring a cuton filter
4. Significantly improving the out-of-band blocking to Tabs <= 0.03%T
5. Edge-blackening each filter to reduce stray reflections

The incredibly high (>97%T) transmittance in the bandpass achieves the highest performance available.  The 100% coated construction using hard, sputtered coatings on 1/4-wave single fused silica substrates and no colored glass achieves long-term durability for consistent research over many years.

The following is a spectral compilation of actual scans of the Astrodon Photometrics Gen 1 Sloan filter set.

These filters are parfocal with all Astrodon LRGB and narrowband filters.

Specifications:

• 50% transmission points provided above (+/- 3nm typical) (click here)
• Peak transmission guaranteed > 95%  (>90% for u')
• <0.1%Tave out-of-band 300 - 1100 nm
• Striae-free, single fused silica substrates
• 1/4-wave propagated wavefront prior to coating
• <0.5 arcminute substrate parallelism
• 3.000 +/-0.025 mm substrate thickness
• 1.25" mounted
• 49.7 mm dia. unmounted
• 49.7 x 49.7 mm square unmounted
• Proud supplier to Las Cumbres Observatory Global Telescopes, AAVSO and research organizations worldwide
• Proudly made in the U.S.A.