Wednesday, December 28, 2016

Astronomik UHC Clip-Filter Test

While in Baltimore visiting my sister for Christmas, I had the opportunity to test out my Astronomik UHC Clip-Filter. According to Astronomik, the Ultra High Contrast (UHC) filter allows the transmission of nearly 100% of the radiation from both O-III and the H beta lines. Annoying scattered light from other wavelength sources, including local artificial light pollution, is filtered out. As a result, detail becomes visible for gas nebulae and planetary nebulae.

I am especially interested in this as I would like to get a decent image of the Orion Constellation with Barnard's Loop, the Flame Nebula, and etc. I attempted this a week ago with partial success in that I did get some of Barnard's Loop, however, light pollution (bad gradient) near the bottom of the image made it impossible to resolve. It may have been do to excessive Christmas light pollution. I want to try this again with no Christmas lights and with the UHC filter but wanted to do a a quick test before I do it for real.

The test was done in downtown Baltimore with heavy light pollution with two lenses. The first test was done with my Opteka 6.5 mm Fisheye lens and the second test was done with my Canon EF 50 mm f/1.8 lens (this is the lens that I want to do the constellation image with). Of course it was slightly out of focus on the UHC image with the fisheye lens.

Opteka Fisheye
Astronomik OWB - 30s, ISO 800

No Filter - 30s, ISO 800

Astronomik UHC - 30s, ISO 800

Canon 50 mm
Astronomik OWB - 10s, ISO 800

No Filter - 10s, ISO 800

Astronomik UHC - 10s, ISO 3200

Processing the image a bit

The results are promising as only the UHC Filter image shows the the Horsehead and Flame Nebula along with the Orion Nebula using the 50 mm lens. The other images only show Orion. The ISO was set at 3200 for the UHC shot, however, non UHC images were white when I set the ISO at 3200.

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