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Triad filter on Luminence channel of Monochrome camera

astrophotography ccd CMOS filters imaging
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#1 Mark Eby

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Posted 04 July 2020 - 06:26 PM

I thought I'd post the results of using a Triad Ultra filter on the Luminance channel of a monochrome camera for the purpose of color imaging. Before buying the filter (used) I had searched to see if someone had tried this technique, but surprisingly, could not find any examples. The theory is to gain the advantage of using narrow-band filters on the L channel, but do it all in one session, instead of splitting time between, say, an Ha and O-II filter.

 

I decided to try it on a faint nebula, Sh2-115, and here are the results:

 

Sh2-115_T.jpg

Sh2-115_L1.jpg

Sh2-115_L2.jpg

The first image is using the Triad filter. Note both stars and nebula are quite visible.

The 2nd image is using the Luminance filter with intensity adjusted so the stars match the Triad image. Note that the nebula is barely visible.

The third image is also using the Luminance filter but with intensity increased so the nebula matches the Triad image. Note the stars are way overpowering.

 

The full color image (with more total exposure time) is here:

https://www.cloudyni...7668_147630.jpg

 

Of course, this technique would not give the color separation that using 2 or more narrow-band filters would, and it certainly can't be used for false-color imaging. But I think it is clear that this technique is quite usable.

 

In the future I may get some real narrow-band filters and see if this really offers a time-saving advantage over using multiple narrow-band filters for the Luminance on true-color images.

 

Details:

Scope: StellarVue SV70T with SFFR-70APO FR/FF

Camera: ZWO ASI1600MMC Pro, LRGB enhanced filters

Exposure: Luminance (15) 120 secs, gain 139; Triad (15) 120 secs, gain 300

 

Questions, comments are welcome.

 


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#2 artem2

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Posted 05 July 2020 - 11:25 AM

Very nice results, I did also do same but using the STC DUO-BAND FILTER with a MONO CCD and the results were  very nicewaytogo.gif ..

 

The TRIAD filter is also on my wishlist, but for the momnt I am very happy with my STC DUO-BAND Filter..

 

Regards

 

Martin


Edited by artem2, 05 July 2020 - 11:27 AM.


#3 YAOG

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Posted 05 July 2020 - 12:07 PM

I thought I'd post the results of using a Triad Ultra filter on the Luminance channel of a monochrome camera for the purpose of color imaging. Before buying the filter (used) I had searched to see if someone had tried this technique, but surprisingly, could not find any examples. The theory is to gain the advantage of using narrow-band filters on the L channel, but do it all in one session, instead of splitting time between, say, an Ha and O-II filter.

 

I decided to try it on a faint nebula, Sh2-115, and here are the results:

 

attachicon.gifSh2-115_T.jpg

attachicon.gifSh2-115_L1.jpg

attachicon.gifSh2-115_L2.jpg

The first image is using the Triad filter. Note both stars and nebula are quite visible.

The 2nd image is using the Luminance filter with intensity adjusted so the stars match the Triad image. Note that the nebula is barely visible.

The third image is also using the Luminance filter but with intensity increased so the nebula matches the Triad image. Note the stars are way overpowering.

 

The full color image (with more total exposure time) is here:

https://www.cloudyni...7668_147630.jpg

 

Of course, this technique would not give the color separation that using 2 or more narrow-band filters would, and it certainly can't be used for false-color imaging. But I think it is clear that this technique is quite usable.

 

In the future I may get some real narrow-band filters and see if this really offers a time-saving advantage over using multiple narrow-band filters for the Luminance on true-color images.

 

Details:

Scope: StellarVue SV70T with SFFR-70APO FR/FF

Camera: ZWO ASI1600MMC Pro, LRGB enhanced filters

Exposure: Luminance (15) 120 secs, gain 139; Triad (15) 120 secs, gain 300

 

Questions, comments are welcome.

 

Can you just use Photoshop to do a color separation? 



#4 Mark Eby

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Posted 05 July 2020 - 12:33 PM

Very nice results, I did also do same but using the STC DUO-BAND FILTER with a MONO CCD and the results were  very nicewaytogo.gif ..

 

The TRIAD filter is also on my wishlist, but for the momnt I am very happy with my STC DUO-BAND Filter..

 

Regards

 

Martin

I tried to find some of your images, but the link to AstroBin is broken, and there are no images in CloudyNights. Is there any other location?



#5 Mark Eby

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Posted 05 July 2020 - 12:38 PM

Can you just use Photoshop to do a color separation? 

I'm not sure what that would buy you. The advantage of the Triad (or any other narrow-band filter) is that excess star-light is not captured in the first place. Using PhotoShop to separate colors and process them separately is a post-processing technique that can be used regardless of how the data was captured. I hope I understood your question correctly and helped to answer it.

 

Mark



#6 artem2

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Posted 05 July 2020 - 12:52 PM

Ohh thank you Mark Eby, for reminding me about astrobin, my entire data " only 10 images blush.gif " were erased few months ago, did then delete my accouint there.

I will try to search the image taken with STC + MONO CCD.. must be somewhere..

 

Will also change the link in my profile, I now have all my images on flickr..

 

Cheers

 

Martin


Edited by artem2, 05 July 2020 - 12:56 PM.


#7 YAOG

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Posted 05 July 2020 - 01:17 PM

I'm not sure what that would buy you. The advantage of the Triad (or any other narrow-band filter) is that excess star-light is not captured in the first place. Using PhotoShop to separate colors and process them separately is a post-processing technique that can be used regardless of how the data was captured. I hope I understood your question correctly and helped to answer it.

 

Mark

Hi Mark,

 

My bad, I realized these are shot mono. The multi-band filter separation technique I've used with my OSCs won't work, DOOH! 

 

Clearly this is a solid technique with more bands used in a single session, I tried a similar thing a while ago using Astronomik CLS CCD in place of the luminance filter with a conventional LRGB filter set on a mono camera. I think there is an advantage to capturing separate NB files in that you have control over the layers. If you have an OSC or DSLR camera try using the Triad on it, you get a lot of control in the color channels you cannot get using the narrow multi-band filters in mono. These newer filters have me thinking of going back to an OSC and using the multi-band filters, they will likely get even better and cheaper over time. 


Edited by YAOG, 05 July 2020 - 01:51 PM.



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