- 1.2-inch OIII (500.7) 3 nm Narrowband Filter
- Parfocal for systems f/4.0 or slower
- Transmitted wavefront better than 0.25 waves/inch
- Made in America
Chroma 1.25" OIII 3nm Telescope Filter
The Chroma 1.25-inch OIII 3 nm Narrowband Filter is essential for imaging objects, like nebulae, that are rich in ionized oxygen atoms. These line emission filters work extremely well in heavy light polluted areas and allow you image on nights when the moon is up.
Chroma manufactures the highest quality astronomy filters with durable, sputtered hard coating using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission.
Highly precise and accurate, the pass-bands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity.
Too tall for a filter wheel.
I can't say anything about using the filter - I assume it's going to be as good as it gets, but potential buyers should know that the housing of the 1.25" mounted filter is oddly tall (maybe 8 mm?) and it won't fit in either my QHY or ZWO filter wheel. I'm going to have to go buy a cheap filter just to switch out the housing - an added expense on an already very pricey item.