Astromania 1.25" O-III Filter - Enhances Contrast During Visual Observation of Gaseous and Planetary Nebulae in All Sky Conditions, The Veil, Ring, Dumbbell and Orion Nebula, Among Many Other Objects

The published spectral transmission plot shows only the visible light range. If you're using this on a monochrome camera without an IR-block filter, be aware this filter does not attenuate IR very much, in fact it has more transmission at 840 and 920 nm than it does in the nominal passband of 500-520 nm. Attached plot of absorbance was taken with an Ocean Optics USB2000 spectrometer.

Using this excellent quality filter for a Unistellar Telescope. It does as it is supposed to do. Very satisfied with it.

Good item .

I ended up returning it so that I could afford an Optolong L-extreme and I don't want to spend time manually layering it with hydrogen-alpha, but I really liked this filter while I had it. My favorite shot was of the Moon using it. It did an incredible job highlighting craters, to my surprise. I was just doing it as an experiment, and it came out looking pretty cool.

Came packaged nicely and was able to see a significant difference while using it, good value for the money.