Hi Andrea,
The Antlia RGB Ultra is a brand new filter that is touted as being able to provide improved views of reflection nebulae and galaxies, as well as emission nebulae.?
It is apparently able to achieve this magical feat by having three distinct pass bands:? one at Halpha (656nm), one at O-III (500nm), and one in the blue part of the spectrum (430nm).? Given my experience testing many types of filters under light polluted skies, I was skeptical about the filter and decided to buy one to try.? The M42 comparison images at the front of my Flickr folder are from the first test I did, evaluating how the RGB Ultra performs compared to a range of other typical filters.? The RGB Ultra performed pretty much as I was expecting:? slightly more contrast on the emission nebulae part of M42 than the UV/IR cut and IDAS LPS-D2, but not any significant improvement on the reflection part of the Running Man.? Unfortunately I don't think there is a silver bullet filter that improves contrast on reflection nebulae under light polluted skies.? Reflection nebulae emit over too broad a wavelength range to be effectively isolated from light pollution.? I may do a couple more tests with the filter, such as on a galaxy for completeness, but otherwise I think the filter's journey is done.? I am waiting however for another new filter to come in from Astro Hutech that has more potential.? It is essentially an IDAS NBZ but it also has a pass band in the near infrared part of the spectrum.? The filter is called the Galaxy & Nebula Booster, and I think it has the potential to work very well.? A prototype has already been tested by Cuiv the Lazy Geek on his Youtube channel.? He lives in Tokyo and so has more direct access to new products coming out of IDAS which is situated in Japan.? If you are interested, I will keep you informed of how things go with the GNB filter.
Cheers,
Jim T.
