Optolong IR Pass685 Planetary Filter 2″

1.  IR Pass685 Introduction

Optolong IR Pass 685nm filter is designed to block wavelengths below 670nm and can be used in IR-LRGB imaging to produce a sharper luminance image for the best planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths.

The sensor of CCD or CMOS cameras is capable of detecting light in the 350-1100nm range including infrared wavelengths. Thus RGB planetary images taken with IR as the luminance channel have visible-enhanced contrast and surface detail than standard LRGB images.

2. IR Pass685 Spectrum and Characteristic
Sbustrate: B270
Thickness: 1.85mm
Tave:  T>90%
Blocking range: 350-1050nm
Blcoking depth: light pollution  line blocking >99%
Surface quality: 60/40
Transmitted Wavefront RMS: λ/4
 Parallelism: 30s

How to read the chart?

▲The horizontal axis is the Wavelength in Nanometers(nm).

▲The vertical axis is transmission in %.</spa