CLS filters are broadband filters, which means they allow wide incident light wavelength ranges to pass through. They block light only in selected sections of the spectrum. These blocked sections are chosen in such a way that they coincide with the emissions from artificial light sources. In addition to artificial sources, there are also natural sky brightness phenomena, which are also blocked by CLS filters. Ultimately, the sky background appears darker with a CLS filter. The object being observed stands out more clearly against the background.
Omegon
Filters Nebula/ city light filter 1.25 ''
$ 39.90
Vaonis
Filters CLS Filter for VESPERA
$ 236.00
Omegon
Filters Light Pollution Filter, 2”
$ 59.00
Optolong
Filters L-Pro 2''
RRP:
$ 216.00
Our price:
$ 205.00
Optolong
Filters L-eNhance 2"
$ 247.00
Optolong
Filters L-Quad Enhance 2"
RRP:
$ 247.00
Our price:
$ 236.00
Omegon
Filters 1.25'' deep sky filter
$ 89.00
Optolong
Filters L-Pro 1.25''
RRP:
$ 164.00
Our price:
$ 154.00
Optolong
Filters L-Pro Canon EOS R Clip
RRP:
$ 308.00
Our price:
$ 247.00
Optolong
Filters L-eNhance 1.25
RRP:
$ 195.00
Our price:
$ 185.00
Optolong
Filters L-Pro Filter 77mm
RRP:
$ 370.00
Our price:
$ 296.00
Optolong
Filters L-Ultimate 1,25"
$ 267.00
Omegon
Filters Pro 2'' CLS filter
$ 99.00
Omegon
Filters Pro Nebula CLS Deep Sky Filter 1,25''
$ 69.00
Optolong
Filters L-Pro Clip Sony Full Frame V2
$ 247.00
Celestron
Filters CLS RASA Origin
$ 350.00
Optolong
Filters L-eNhance APS-C EOS Clip
$ 278.00
Skywatcher
Filters Light Polution CLS 2"
$ 45.90
Optolong
Filters Clip Filter for Canon EOS APS-C CLS
RRP:
$ 102.00
Our price:
$ 82.00
Astronomik
Filters 1.25" CLS filter
$ 82.00
Omegon
Filters 1.25'' Clear Sky filter
$ 129.00
Astronomik
Filters 2" CLS CCD filter
$ 236.00
Optolong
Filters Clear Sky Filter 77mm
$ 175.00
Astronomik
Filters CLS Canon EOS XL Clip
$ 185.00
Astronomik
Filters CLC Canon EOS clip filter APS-C
$ 133.00
Optolong
Filters Clip Filter for Canon EOS FF L-Pro
RRP:
$ 360.00
Our price:
$ 246.00
Skywatcher
Filters Light Polution CLS 1.25"
$ 32.90
Optolong
Filters L-Pro Clip Sony Full Frame
RRP:
$ 288.00
Our price:
$ 250.00
Chroma
Filters LoGlow Light Pollution 2"
RRP:
$ 910.00
Our price:
$ 590.00
Optolong
Filters Clear Sky Filter 82mm
$ 226.00
Optolong
Filters Clip Filter for Canon EOS APS-C CLS-CCD
RRP:
$ 133.00
Our price:
$ 99.00
Astronomik
Filters CLS CCD EOS clip filter
$ 164.00
Antlia
Filters Quad Band Anti-Light Pollution 2''
$ 278.00
Explore Scientific
Filters 2" CLS filter
RRP:
$ 86.00
Our price:
$ 59.00
Astronomik
Filters CLS XT Clip Canon EOS APS-C
$ 154.00
Explore Scientific
Filters 1.25" CLS filter
RRP:
$ 60.00
Our price:
$ 41.90
The figure below illustrates the principle using the example of the NGS1 filter from IDAS. The black transmission curve shows which wavelength ranges the filter allows to pass through. 100% would mean no filter effect at all. The transmission curve also shows which light wavelength ranges are blocked by the filter. These ranges are associated with the emissions from sodium-vapour lamps and other disruptive light sources. The CLS filter filters out this unwanted light.
The CLS filter allows broad ranges to pass through and is therefore also suitable for small optics.
