Astromania 2" UHC (Ultra High Contrast) Filter - Superb Views of The Orion, Lagoon, Swan and Other Extended Nebulae

If you want poor purple objects and out of focus this is your filter. The glass used is distorted and the coating makes all objects a haze looking purple. I wish I could have retuned it but it is too late. Shame I never had clear skies in the return window to test it out. Now that I have I can safely say they have poor QC.Seems some people get good ones and others( such as myself ) get really poor ones. Stay away or take your chances.

I only used this filter to photograph the Veil Nebula, which is very difficult even to find in the sky. With this filter, is much easier, as the photo of a single exposure can show.However it completely kills the color! It casts a very green color which is fine to correct on any photo software after stacking. But the color will be gone forever.-------Edit 2022-02-06: As some had already said, this is filter that only passes Hb and Oiii. Still useful for some targets, but is far from a broadband filter.

I am using this on a Step Down ring to take pictures of Milky Way and nebula with a DSLR. The UHC filter introduces about 3 stops, though that will vary depending on the target. It definitely darkens the sky and removes ambient light. The filter seems to be well made with uniform coatings. I have no way of evaluating it in a more qualitative manner but it seems a good value and I'm happy with the purchase.As an aside, I do get a bit of vignetting at 12mm on a 12mm-50mm f/3.5-6.3 kit zoom, filter diameter 52mm, but that goes away at 15mm and isn't really a problem as it only darkens the corners a bit. If it were a faster lens, I'd need to go with "full size" filters but this suits my current setup just fine.

So I will admit up front I do not have scientific equipment to measure light frequency pass-thru and fall-off. What I do have is a repeated set of deep sky images that are true to color without some of the annoying man made light pollution. What's interesting is I have a Canon camera insert version of this that seems to make the images more pink and purple, as if it is blocking more of the green.I also have a CLS filter, but I prefer the UCH as it seems to do a better job for me.

It works pretty well for what's advertised, amd with the price, you cant complain much

This filter does let Ha pass through! See image of California Nebula which is almost entirely a Ha emitter. As well as SII and OIII this filter is incredible for the price!

This filter only passes the light around the 400nm line. It does not transmit the Ha and higher. Filter works great but I thought that should be a heads up.

The filter had outstanding color and detail plus enhancements.