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Old 17-01-2018, 11:38 AM
glend (Glen)
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New Dual Narrowband Filter for OSC

Cyclops Optics, of Hong Kong, has launched the STC Astro Duo-Narrowband filter. This filter passes two critical 10nm narrowband lines Hydrogen-alpha and Oxygen-III simulateneously at a very high transmission rate, enabling narrowband imaging with one-shot-colour (OSC) camera and DSLR with high efficiencies even under heavily light polluted sky (according to their info). Available in 48mm and Clip-in versions, at $329 USD with free International shipping,
For all the info click on the product description link on the page below.

https://www.cyclopsoptics.com/astron...7-8bbc10b55357
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Old 17-01-2018, 11:57 AM
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Quote:
Originally Posted by glend View Post
Cyclops Optics, of Hong Kong, has launched the STC Astro Duo-Narrowband filter. This filter passes two critical 10nm narrowband lines Hydrogen-alpha and Oxygen-III simulateneously at a very high transmission rate, enabling narrowband imaging with one-shot-colour (OSC) camera and DSLR with high efficiencies even under heavily light polluted sky (according to their info). Available in 48mm and Clip-in versions, at $329 USD with free International shipping,
For all the info click on the product description link on the page below.

https://www.cyclopsoptics.com/astron...7-8bbc10b55357
This could be a game changer then Glen, for City bound narrowband folks, without much time on their hands, or DSLR folk like myself.
I have the Astronomik CLS filter ; does a decent job....this is going to be better it seems.
bigjoe.
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Old 17-01-2018, 01:54 PM
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luka
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Looking at the transmissions of a typical DSLR CCD sensor with a Bayer matrix the Ha will only go to the red channel while the O-III will only go to the green and blue channels.

So it should be possible to split up the RGB channels and get Ha O-III narrowband images with Ha in the Red channel only and then add the GGB channels to get the O-III data only.

Of course there are tradeoffs compared to the real narrowband:
1. the resolution will be 1/4 of the full sensor resolution.
2. the efficiency will suffer.
Only a 1/4 of pixels for Ha are used and unmodified DSLRs have a poor Ha transmission rate already.
It looks better for O-III though, with 3/4 pixels actually being used at about 50% transmission rate for each pixel (dependent on the Bayer matrix, the figure of 50% comes from the example transmission rates in the linked image).
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Old 17-01-2018, 04:49 PM
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Originally Posted by luka View Post
Looking at the transmissions of a typical DSLR CCD sensor with a Bayer matrix the Ha will only go to the red channel while the O-III will only go to the green and blue channels.

So it should be possible to split up the RGB channels and get Ha O-III narrowband images with Ha in the Red channel only and then add the GGB channels to get the O-III data only.

Of course there are tradeoffs compared to the real narrowband:
1. the resolution will be 1/4 of the full sensor resolution.
2. the efficiency will suffer.
Only a 1/4 of pixels for Ha are used and unmodified DSLRs have a poor Ha transmission rate already.
It looks better for O-III though, with 3/4 pixels actually being used at about 50% transmission rate for each pixel (dependent on the Bayer matrix, the figure of 50% comes from the example transmission rates in the linked image).
.

Yep typical , and oh so true..
Hard to have your cake and eat it too..I guess.
bigjoe.
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Old 17-01-2018, 07:43 PM
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As Spock would say; Fascinating!
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Old 18-01-2018, 08:34 AM
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What a clever idea.

Greg.
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