Astronomik L2 UV+IR Blocking Luminance Filter

Astronomik L2 UV+IR Blocking Luminance Filter

  (4 Reviews)
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About this product

Model:  ak_uv-ir_l-2_125
Part Number:  10162125

Astronomik offers you a range of three different UV+IR blockers as Luminance filters. The different spectral window of each new Luminance filters is designed to tune your setup to get the sharpest image from any optical design and any camera

The Luminance channel is probably the most important for a great final image! You want as much signal as possible so the filter should have the highest transmission possible with a wide spectral bandpass. This combination provides the greatest sensitivity and gives you the highest photon counts on your pixels.

While the high transmission level is a great aspect of the new Astronomik Luminance filters, not all optical instruments or additional optical elements like correctors, field-flatteners or reducers, have perfect colour correction so it can be the width of the spectral band pass of  the Luminance filter that can cause problems.

A band pass that is too wide will allow the transmission of incompletely focused light (Chromatic aberration), making stars appear soft or bloated. In such cases image processing can become difficult, so having a slightly narrowed spectral window in your Luminance filter can reduce or eliminate this damaging effect. 

L1, L2 or L3?

If you use an optical system that is completely free of any chromatic aberration you should get an L1 filter for your setup.

For general use the L2 filter is well suited to most optical systems with a corrector, flattener or reducer in the optical train.

The L3 filter is designed for users of refractors with a less-than-perfect colour correction and in combination with the new Deep-Sky RGB filters, the L3 filter will minimise the problem of bluish halos around stars.


  • Free of halos and reflections
  • Not sensitive to high humidity or ageing effects
  • Scratch-resistant!
  • Excellent quality substrate, diffraction limited - the optical performance of your telescope will not be reduced
  • Parfocal with other Astronomik filters
  • 1mm Glass Thickness
  • Supplied in a high-quality, long lasting, filter box

Additional note for observers working under light polluted skies:
If your observing site suffers from light pollution you should try to use our CLS-CCD as a replacement for the Luminance filter. The transmission curve of the CLS-CCD will give you approximately the same amount of energy in all three colour channels while blocking nearly all unwanted arifical light pollution. Customers who replaced the Lx filter with the CLS-CCD are amazed by the increased quality of their data. This small change gives you the opportunity to take much deeper images from your current observing site.

Transmission Chart


Customer reviews

Average Rating (4 Reviews):  
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Rating (max 5):  
Just the job
22 February 2023  | 

After struggling with an LPS filter on my modded 700D, FLO recommended this filter for better colour balance. It's excellent! Nice clear images and stars are much easier to process, colour balance is spot on. Also a very good partner for my dual band nebula booster.

Rating (max 5):  
Not a good fit in Nikon Z Full Frame bodies
27 October 2021  | 

I bought this filter as part of a set of four for a full spectrum converted Nikon Z6 to allow normal photography (with this filter) and IR photography with IR Pass filters.

As soon as I received them, I put one into the Z6 but found that contrary to the Astronomic sales video the filter dropped out at the slightest nudge of the camera. I've tried other full frame Z bodies with the same results. Yes, the filters stay put in the bodies, just, but it only requires the slightest nudge for them to drop out, I certainly cannot replicate what the video shows of multiple reasonably forceful taps without dislodging the filters.

Obviously, a lens or T mount holds any filter in place so for Astrophotography or where you want to fit a lens for a whole shoot it is not a big problem. So, if you are willing to accept a loose fit they are good.

Iíve watched the install video several times to check Iíve not missed anything subtle in the fitting and have tried multiple times with the same result. There are no sprung pieces on these filters that engage with the ridges in the Z body cavity, so they rely on the size being correct for an interference fit - other manufacturers Z clip-ins have a form of spring retention on the upper edge that does work.

I did take the time to test and check all four filters received and as far as filter quality is concerned, they are great but fitting wise and staying in place is concerned they are no good for me. Other clip in filters, not Astronomik, fit and stay fitted fine, so, I have returned them and will buy alternatives. I've given three stars as the filter quality is good, but the fitting is not.

Rating (max 5):  
I think it works.
07 May 2021  | 

Used with my full-spectrum modified Sony a7S. I haven't carried out exhaustive tests with/without the filter, but with the filter there appears to be no star bloating due to excess infra-red light.

Rating (max 5):  
Totally worth the ££
20 January 2021  | 

So happy with this filter. I bought the ZWO 533 and forgot to order a UV IR cut filter. Shooting the Iris nebula resulted in the main bright orange star near it being pinkish purple. This filter completely tightened all the stars up and corrected the colour which was slightly off too! I'm using this alongside a Canon 70-200 2.8 IS II and 1.4 III extender which generally has very well corrected optics. No halo issues, great quality as I'd expect from Astronomik.

Something to consider when looking for UV filters is if they're par focal, this can be *extremely* helpful and time saving when going between filters!


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