The SkyTech CLS (City Light Suppression) filter is designed to improve the visibility of various deepsky objects by blocking light pollution, while allowing light from deepsky objects through. Solves the problem where many telescope adapters are not suitable for filters and protects your expensive camera chip from dust.
How does it fit the camera?
The filter is designed to simply clip directly in front of the sensor and is easily removable, still allowing lenses or adapters to work, also protecting the sensor from dust. Click the main product image to see how it fits in.
SkyTech CLS filters are suitable for unmodified Canon DSLRs. The CLS has a wider pass-band than a narrower UHC filter, so it gives a more natural colour response than a UHC filter. CLS is therefore best for mild to moderate light pollution filter for suburban skies.
Compatible with all APS-C sized Canon EOS cameras. Not for full frame cameras. Do not use with EFS lenses because the rear elements can strike the filter.
How this filter works: Artificial lighting such as mercury vapour lamps, both high & low pressure sodium vapour lights and unwanted natural light caused by neutral oxygen emission in our atmosphere (skyglow) are almost completely suppressed by the SkyTech CLS filter.
The filter selectively allows light from deepsky objects through, with high transmission of ionised oxygen O-III (496nm & 500nm), Hydrogen Beta / N-beta (486nm), N-II(654nm and 658nm), H-alpha(656nm) and S-II(672nm).
By selectively blocking light pollution and transmitting these desirable wavelengths, the contrast and detail of deepsky objects is greatly enhanced.
Schott glass substrate material with precision polish.
Glass thickness 1.0 mm.
Surface Quality: 60/40 (Refer to MIL-O-13830)
Fine-optically polished to ensure accurate 1/4 wavefront and < 30 sec parallelism over both surfaces
95% transmission of main nebula emission lines (i.e. Ha 656nm, OIII 496nm & 500nm, SII 672nm and H-beta 486nm).
0.1% transmission of off-band, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm).
Dichroic Filter Coatings:
Multi-layer anti-reflection coating (AR Coat).
Special high homogeneity coating process with electron-beam gun evaporation and Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL (central wavelength) no deviation with temperature change.
Absolutely Brilliant! From initial contact and enquiry, to product order, delivery, and after sales service, Harrison Telescopes is a shining example of how business online should be done. I can't recommend them highly enough. I will certainly be buying from them again in the future. Thank you! Best wishes, Steve. (08/02/2020) Steve Bowling - North Wales
SkyTech CLS Filter Purchased this to reduce the increasing amount of light pollution in my back garden. Tested it for fit in my Canon D600, no problem. Just waiting for clear sky's. It wont be the only filter in my kit. Hope to improve my astrophotography as I gain experience. (13/12/2019) Nigel Capon - Maidstone, Kent
Easy transaction well priced, good product, quick delivery, I couldn't have asked for more. (25/10/2019) ChrisH - Amersham
Excellent AS always with Harrison's the Quality is Excellent. And the Helpful service and price is second to none. And the Delivery is very quick I ordered 3 items from them on Sunday Night and they arrived just after 12 O clock on Tuesday.Thank you Harrison's. (15/06/2019) Patrick - Long Rock Cornwall
excellent service fast deliver will be using this company again (04/05/2019) kriss - midlands
Seems Decent Only had a single session with this filter so far. On top of that i've only used it for some wide field, untracked exposures in a 50mm lense. Shots with the filter produce a much darker sky than without, but also tint the stars a heavy pink/purple and blue, using with an unmodified DSLR. (12/04/2019) Paul - Gateshead
Our Reply: You may find colour sensitivity shift a little with many filters, unmodded DSLR's will especially but slight adjustments in processing should help - the effect you have seen can sometimes be caused by dew starting to form on the optic diffracting the ligh.
Excellent filter My EOS750D has been modified with a Baader BCF filter with a cutoff beyond H-Alpha, so didn't need the extra filtering of a CLS-CCD. Used the CLS filter for the 1st time last night. First time I've been able to use a long-enough exposure to photograph M97 Owl Nebula. Great results. Thanks (08/03/2019) Mike Curran - Teignmouth, Devon
Once again excellent service and product,have bought from Harrison's before and would recommend to anyone to buy from them,their prices are normally the best.Clear skies to everyone (01/03/2019) Stephen Palfrey - Exmouth, Devon
skytech cls clip filter A marked improvement on previous night sky photography shots,a more natural looking result every time. (15/02/2019) t pearman - west london
I can't believe the difference it has made already and I've only used it for one astrophotography session! I'm looking forward to future sessions and I will definitely be buying more filters soon. The delivery and service were also five star,but I knew that from purchases in the past! (13/01/2019) Zoe -
Excellent results Great results so far only had a small amount of time to try out the filter but already showing great promise to do what it was purchased for, to get rid of the damn street lighting. (11/01/2019) Phil Jones - St. Helens
Superb Extra I live in a urban environment and just getting into Astrophotography. Fitted this filter and what a difference, no more pink glow after a long exposure. (10/01/2019) Ian Paterson - Jarrow, Tyne & Wear
excellent results easy to fit and great results (05/10/2018) jim - ramsgate
Amazing boost in contrast Living in a light polluted area its always been hard to capture faint detail in nebulae but using this filter I could see nebulousity in just 1 minute exposures and the final image has much more detail and contrast than without (15/06/2018) AF -
it's not such a good fit I have a CANON 60 DSLR I find the filter falls out when you turn it over without a lens fitted, otherwise it does the job when the lens is attached.THANK YOU FOR THE SERVICE I'V HAD WITH ANY OTHER ITEMS I PURCHASED. (10/03/2018) Robert Anderson - Paisley
Our Reply: Hi, You can adjust the two spring slots with a small screwdrive, a small twist will tighten the grip and prevent rattle or the filter coming out when inverted - I have emailed you an image showing how to do this easily, thank you for the feedback.
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