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Sunday, January 13, 2008

Narrow Band with UHC-s and H-alpha????

This is a very interesting test run! I started to think, if I use UHC-s filter to capture colors to my H-alpha luminens, what other information UHC filter might captured? The UHC-S filter is a multi bandpass filter made so that only some portions of light in the visual the spectrum are transmitted. This UHC-S will pass a total of about 100 nanometers within the 400 to 700 nma range, with high percentages of transmission of that light in the portions of the spectrum commonly emitted by emission or diffuse nebula Here is the spectral responce curve for the filter.

As you can see there is spike at about 500 nm containing both O-III and H-Beta, In singleshot camera those bands are ending up partly to Green and Blue channels!!!There is lots of H-alpha as well, but we are not interested about that, becouse we have separate 7nm H-a filter data. So this is a background and here are few samples what can be archived with that data.

This is a very first test run and there is lots of things to test, but it looks promicing so far.

All images have been taken with QHY8, a sigle shot cooled 6mb astro camera.

original H-alpha 16 x900s + 5 x 1800s light frames used. Total exposuretime about 6,5 hours. LX200 GPS 12" f6.3 + SXV-AO (Active Optics system) Elephants trunk nebula in IC 1396 This is pure RGB data with Baader UHC-filter 5x900s

Final RGB image, combined from previous images.

Lights: 5x1800s + 15x900s @H-alpha Color data: 5x900s UHC-s filter combined as HaR(Ha)GB

Hubble palette test from the same original data RGB > BRG and some color balancing Modified palette test from the same original data

Here is the same method used for the Bubble nebula image

Original RGB data.

Exposure time is 4h for H-a and 2h with UHC-s filter for RGB. HaR(Ha)GB image is combined from the data. Modified Hubble palette from the same material as the original RGB Palette variation from the same data

I hope, that someone else will test this method and report here about findings.

All comments and opinions are welcome.


Sander P said...

Great stuff! Thanks for doing this research and publishing the results.

Corne Donkersloot said...


For a long time I visit your site, and you give me an idea to combine different type of filters. Last time I combined a stack of Ha and a Seben orbinar UHC filter. With this UHC you have OIII and SII at >95%, and Ha about <40%.
For info filter:

For one of my pictures: -> Corne Donkersloot -> img 22

About your website, great stuff!

J-P Metsävainio said...

Thanks for commenting.

You have some great image(s)!
Interesting filters, it looks like they both are originally made for visual use, since with imaging UV-cut filter is needed doe leak in Red end of the spectrum.

If you Stack H-a and UHC you gain nothing, since H-a is much narrower and cut away O-III part away.

Best regards,