Astronomik L-2 UV-IR Blocking Clip Filter for Canon EOS APS-C
Astronomik L-2 Filter UV-IR Blocker for AstroPhotography
Mounted filter in EOS Clip Cell
UV and IR cut Filter for digital photography.
We have re-designed all of our photographic filters. Since the end of 2008 we are shipping our new "Halo-Free" filters.
Astronomik now 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.
To give you all the tools to gather the best data possible Astronomik have expanded their line of Luminace filters: Now you can select a Lumiance filter perfectly matched to the kind of telescope you use, to get the highest signal and sharpest image for the Luminance channel!
Depending on the color correction of your scope you may use a wider spectral window for the Luminance data. The L1 filter has the widest spectral window, the L2 is about the same as their original L-Filter and the L3 is much narrower.
If you use an optical system that is completely free of any chromatic aberration (good apochromats) 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 while the L3 filter is designed for users of refractors with a less-than-perfect color correction and in combination with the new Deep-Sky RGB filters, the L3 filter will minimise the problem of bluish halos around stars.
The transmission curve characteristics and coatings on the new Luminance filters have been designed and engineered in such a way that no halos or reflections will be visible. Even with bright stars in the field of view you will be able to reveal the faintest structures in nebulas or galaxies.
Like all Astronomik Filters, the new Luminance filters are made using an extremely durable and scratch resistant coating, deposited on the finest polished optical substrate, which is free of any striae or internal strains. All substrates are made to exactly the same thickness, so all of our filters are parfocal.
Additional notes 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.
The Astronomik UV-IR Blocker lets the full range of sensitivity of the human eye (according to DIN 5031) pass, and blocks all other parts of the spectrum in the UV and IR. The Astronomik UV-IR Blocker is the ideal choice as a luminance filter for any kind of digital photography.
Because of the perfect blocking of UV and IR all optical problems in these parts of the spectrum are avoided.
The filter is optimized for systems with focal ratios between f/0.5 and f/50. The typical transmission is higher than 99%.
The UV-IR Blocker gives you a perfect parfocal filter for the luminance channel. It is also great as a dust protection for your telescope and camera.
- As a dust protection of Schmidt-Cassegrain, Schmidt-Newton or Maksutov system or as a dust protection in front of DSLR camera.
- As an alternative instead of the IR-Blocker if your camera has a high sensitivity at short wavelengths.
- As an alternative instead of the MC Clear if your system has any refracting elements
You should think about using the IR-blocker if your camera has a low sensitivity at short wavelengths. Think about using the MC Clear glass if you have a system without any refracting elements. If you do color imaging from light polluted places, please think about using the CLS CCD filter for the luminace data instead!
- Visual observation (dark skies): It depends, for dust protection only
- Visual observation (urban skies): It depends, for dust protection only
- Film photography: It depends, for dust protection only
- CCD photography: Very good, if used with optics which contain refracting elements
- DSLR photography (MC modified): Very good, if used with optics which contain refracting elements
- DSLR photography (astro modified): It depends, for dust protection only
- DSLR photography (original): It depends, for dust protection only
- Webcam / Video (Planets): Very good, if used with optics which contain refracting elements
- Webcam / Video (Deep Sky): Very good, if used with optics which contain refracting elements
- Parfocal with other Astronomik filters
- Glass thickness: 1mm
- Completely resistant against high humidity, scratches and aging effects
- Diffraction limited, the filter will not reduce the optical performance of your telescope!
- Astronomik filters are delivered in a high-quality, long lasting, filter box
How to read the above chart?
* The horizontal axis is the Wavelength in Nanometers (nm). 400nm is deep blue, at 520nm the human eye senses green and at 600nm red. At 656nm is the famous "H-Alpha" emission line of hydrogen.
* The transmission in % is plotted on the vertical axis.
* The red line shows the transmission of the filter.
* Visual filters: The grey line in the background shows the relative sensitivity of the human eye at night. The maximum is at ~510nm and drops to longer and shorter wavelengths. You can easily see, that you can´t see anything of the H-alpha line at night (even if you can during daylight!) The sensitivity at 656nm is 0% at night!
* Photographic filters: The grey line in the background shows the sensitivity of a typical CCD sensor.
* The most important emission lines from nebulas are shown in green. The most important lines are from ionized Hydrogen (H-alpha and H-beta) and double ionized oyxgen (OIII) .
* The most important artifical emission lines are shown in orange. The artifical light pollution is dominated by see mercury (Hg) and sodium (Na), which are used in nearly all streetlights.
The major emission lines of artifical light pollution:
| Hg 435,8nm | Hg 546,1nm | Hg 577,0nm |
| Hg 578,1nm | Na 589,0nm | Na 589,6nm |
| Na 615,4nm | Na 616,1nm |
The major emission lines of nebulas:
| H-β 486,1nm | OIII 495,9nm | OIII 500,7nm |
| H-α 656,3nm |
Filter image is for demonstration purposes only.