New Dual Narrowband Filter for OSC

[glend]

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/astronomy-filters/stc-astro-duo-narrowband-filter-48mm/?utm_campaign=20180114%20Launch%20S TC%20Duo-Narrowband&utm_medium=email&_hsenc=p2ANqtz-9aZCyt5qVQgFdzZxPh6WprQqyRZsOj3pB5e b0C2yVaOasN-z10QPmeMlZm6EInY8XttOosnYhHjMfyUWH2 PVGICkxsuA&_hsmi=59963817&utm_content=59963817&utm_source=hs_email&hsCtaTracking=85a73276-694a-4b29-b5e7-0ad48295dcf2%7C504ba020-5734-4a11-afe7-8bbc10b55357

[bigjoe]

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.

[luka]

Looking at the transmissions (https://www.dxomark.com/About/In-depth-measurements/Measurements/Color-sensitivity) 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).

[bigjoe]

.

Yep typical , and oh so true..
Hard to have your cake and eat it too..I guess.
bigjoe.

[Andy01]

As Spock would say; Fascinating!

[gregbradley]

What a clever idea.

Greg.