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
Omegon
Filters Light Pollution Filter, 2”
$ 59.00
Vaonis
Filters CLS Filter for VESPERA
$ 242.00
Optolong
Filters L-Quad Enhance 2"
RRP:
$ 252.00
Our price:
$ 242.00
Optolong
Filters L-Pro 2''
RRP:
$ 220.00
Our price:
$ 210.00
Omegon
Filters 1.25'' deep sky filter
$ 89.00
Optolong
Filters L-Pro 1.25''
RRP:
$ 168.00
Our price:
$ 157.00
Optolong
Filters L-eNhance 2"
$ 252.00
Optolong
Filters L-eNhance APS-C EOS Clip
$ 284.00
Omegon
Filters Pro 2'' CLS filter
$ 99.00
Optolong
Filters L-Pro Clip Sony Full Frame V2
$ 252.00
Optolong
Filters L-eNhance 1.25
RRP:
$ 199.00
Our price:
$ 189.00
Optolong
Filters L-Pro Clip Sony Full Frame
RRP:
$ 294.00
Our price:
$ 255.00
Omegon
Filters 1.25'' Clear Sky filter
$ 129.00
Optolong
Filters L-Pro Filter 77mm
RRP:
$ 378.00
Our price:
$ 303.00
Omegon
Filters Pro Nebula CLS Deep Sky Filter 1,25''
$ 69.00
Optolong
Filters L-Pro Canon EOS R Clip
RRP:
$ 315.00
Our price:
$ 252.00
Chroma
Filters LoGlow Light Pollution 1.25"
$ 530.00
IDAS
Filters LPS-D3 Drop-In Canon EF FullFrame
$ 420.00
Optolong
Filters Clear Sky Filter 82mm
$ 231.00
Explore Scientific
Filters 2" CLS filter
RRP:
$ 88.00
Our price:
$ 60.00
Optolong
Filters L-Ultimate 1,25"
$ 273.00
IDAS
Filters Night Glow Suppression Canon EOS APS-C
RRP:
$ 378.00
Our price:
$ 347.00
STC
Filters Astro Multispectra Filter 2"
$ 368.00
Explore Scientific
Filters 1.25" CLS filter
RRP:
$ 62.00
Our price:
$ 42.90
Optolong
Filters Clear Sky Filter 77mm
$ 178.00
Celestron
Filters CLS RASA Origin
$ 357.00
Astronomik
Filters CLS M77
$ 410.00
Celestron
Filters LPS RASA 800
$ 530.00
Astronomik
Filters CLS CCD Sony Alpha Clip filter
$ 252.00
Astronomik
Filters 2" CLS CCD filter
$ 242.00
Astronomik
Filters CLS XL Clip Canon EOS R
$ 210.00
Astronomik
Filters CLS Clip Nikon Z XL
$ 210.00
Astronomik
Filters CLS Nikon XL Clip
$ 210.00
Astronomik
Filters 2" CLS filter
$ 178.00
Astronomik
Filters CLS CCD EOS clip filter
$ 168.00
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.
