Optolong Night Sky H-Alpha (IR Pass 630nm) 2.0″ Filter
1. Optolong Night Sky H-Alpha Introduction
Night Sky H-Alpha filter (IR Pass 650nm) with 50% transition from blocking to passing at about 640nm and 95% or above transmission at wavelengths longer than 650nm 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.
WARNING: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning.
2. Optolong Night Sky H-Alpha Spectrum and Characteristic
- Substrate: Optical glass
- Thickness: 1.85mm
- Tave: T>90%
- Blocking range: 300-570nm
- 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 %.
▲The RED line shows the transmission of the Night Sky H-Alpha filter.