Introduction

The broad-band "Light Pollution Reduction optical filters" are designed to improve the visibility of a variety of Deep-Sky objects by blocking out the common Mercury vapor, Sodium, and some other emission lines from man-made or natural sources which contribute to light pollution, while letting through a broad range of other more useful wavelengths.  Deep-Sky Filter.

Substrate

B270 or Other Glass

Round type size

Φ25~ Φ 78 mm

Thickness

1~ 4 mm

Surface Quality

40/20,60/40

Wavelenth

Transmission

400~450nm

Tave<1%

470~510nm

Tave>90%

550~610nm

Taverage <1%

650~700nm

T>90%