ZWO IR Pass 1.25" Filter

  • Darkens the background during twilight.
  • Imaging of bright planets, stars, and comets by day.
  • Imaging of young stars in dust clouds and stellar nurseries.
  • Filter thickness: 11 mm.
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  • Regular price $22.00

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ZWO IR Pass 1.25" Filter

The ZWO 1.25-inch IR 850nm Pass Filter is suitable for IR sensitive cameras. This filter is great for lunar and planetary imaging systems. It greatly reduces seeing conditions by blocking all wavelengths up to 850 nanometers on the spectrum, allowing only IR light to pass. You can photograph wavelengths where seeing is significantly lower.

If using a color camera, you don’t need to debayer and get the full resolution. Most Color ZWO cameras’ QE response is 850nm. So you can use a color camera as a monochrome camera with this filter, just don’t forget to keep the WB_R and WB_B to 50 (no White Balance applied).


Filter Thickness1.1 mm
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5.0 Based on 2 Reviews
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Robert P.
United States
Works well

I now get double duty from my OSC camera. This converts it to a monochrome IR camera. It does a good job of cutting through the Martian dust.

Great for Mars and Venus

I first used this filter on Venus during broad daylight and it worked wonderfully. The background sky was nice and dark and Venus was very bright so I was able to use very short exposures for faster frame rates. It didn't bring out hardly any cloud detail at all, but that was to be expected. The main benefit is being able to observe Venus when it is nice and high in the sky during the day. Later in the night, I imaged Mars in RGB using the IR 850nm as a luminance filter. WOW did it boost contrast like crazy! To compare, I also imaged Mars through a standard L filter and used it as luminance, but it was much more washed out and hazy. From now on all of my Mars images will be shot in IRRGB. It's a bit hard to believe that a filter that only costs 22 bucks can make such a huge difference in image quality. I also tried shooting Saturn in IRRGB as well which I was hoping would turn out well. Unfortunately, it gives too much contrast between the disk and the rings. The disk becomes very dark in IR, while the rings become very bright. LRGB gave much better results with Saturn. I haven't tried shooting Jupiter in IRRGB yet, but I don't imagine there being any issues like with Saturn. FYI, I am using this filter with a ZWO ASI290MM.