Workflow for STC dual narrowband filter

I've been eyeing those filters myself.  In APP, in the "Combine RGB" tool, when you add the final integration to the tool, it will iterate through all 3 channels of the file and ask what you want to do with them.  (No need to separate the 3 channels into individual files in Photoshop).  So for channel 1, you could assign it to Halpha, channel 2 to something unused, like SII.  Then channel 3 to OIII.  (Or did I get channel 2 and 3 backwards?)  Then you can combine the Halpha and OIII in the tool just like you would from separate files.

I haven't tried this, but it should work.  If you get good results, I may pull the trigger and buy one of the filters. 🙂

-- Kevin

Posted by: Janos

Hi Mabula,

I have started to use this filter in combination with my ASI071MC color camera:  https://stcoptics.com/en/astro_duo_narrowband/

The question is now how to process these images correctly. Practically I have only red and blue, but APP tries to restore a true RGB color balance I suppose. 

Can you give a hint how should I process the images to get the expected bicolor result. These are my attempts so far ( I am not really satisfied yet):

https://www.astrobin.com/351999/B/?nc=user

https://www.astrobin.com/353634/?nc=user

https://www.astrobin.com/352004/?nc=user

https://www.astrobin.com/354936/?nc=user

Clear skies!

Janos

 

Dear Janos @jarbi58,

This is an interesting situation ;-).

So, the filter has transmission for H-alpha (deep Red) and OIII (Blue/Green):

Image from  https://stcoptics.com/en/astro_duo_narrowband/ <:

Yes, by default, APP will debayer with the Adaptive Airy Disc algorithm. This algortihm needs good signal in the green channel to be most effective. So for your filter, I think we might need to choose another algorithm or even create a new one. If there is enough OIII signal in the data, the Adatpive Airy Disc will still work fine, but for objects with little to no OIII, it will not. (Then simply use the H-alpha debayer algortihm for H-alpha output)

For just RGB output, choose the bilinear interpolation and check if the results are different if you look at the colors and star edges.. That is very interesting to know for me.

As you probably know, I have created narrowband debayer algorithms. These will create monochrome h-alpha output of, for instance, H-alpha data shot with an OSC/DSLR directly.

For your filter, I might be able to implement a specialised debayer algorithm as well. Perhaps with the option to create monochrome output(like a luminance) or a bi-color in a balanced way.

If you can share some of your frames shot with the filter, I will be happy to work on this for the next release 😉

Regarding your images, they do look good, but probably H-alpha is overpowering the OIII signal quite a bit, which is normal. Have you tried the RGB Combine tool and boosted the blue channel with respect to the red channel?

NGC7000 by Janos Barabas @jarbi58:

Kind regards,

Mabula

Posted by: kross

I've been eyeing those filters myself.  In APP, in the "Combine RGB" tool, when you add the final integration to the tool, it will iterate through all 3 channels of the file and ask what you want to do with them.  (No need to separate the 3 channels into individual files in Photoshop).  So for channel 1, you could assign it to Halpha, channel 2 to something unused, like SII.  Then channel 3 to OIII.  (Or did I get channel 2 and 3 backwards?)  Then you can combine the Halpha and OIII in the tool just like you would from separate files.

I haven't tried this, but it should work.  If you get good results, I may pull the trigger and buy one of the filters. 🙂

-- Kevin

 

Thank you @kross for sharing your thoughts on this 😉

I agree, the balance from the H-alpha and OIII signals could be found to create a nice Bi-Color, using the RGB combine tool. I would assign H-alpha to Red, and OIII to both green and blue. Then increase the multiplier for the OIII data, probably somewhere to 2-4. That should already give a more balanced results I suspect.

A more fine tuned results would be to mix it up a little bit more, but perhaps I can demonstrate that if Janos @jarbi58 sends me some of his data.

Cheers,

Mabula

I'm using a modified DSLR, and would like to start narrowband imaging. The dual narrowband filter looks like an inexpensive way to get started.  APP is also my image processing program of choice, so I'm anxiously awaiting the results of this, to make a decision if I should spend the money on the dual filter, or just put that money into saving for a "real" setup (mono CMOS astro camera, filters, filter wheel, etc.).

Hi Mabula and other,

Thanks for your replies and ideas so far, please feel free to experiment with my NGC7000 data:  https://drive.google.com/open?id=1XIVTdFaAwvRSMW2Q6ZjYJ9HJzGF9G0Ez

I will certainly do further tests with the suggestes workflows and hopefully I can shoot more images as well 😉

Cheers,

Janos

Hi,

Some more data to experiment with from the SH2-101:  https://drive.google.com/open?id=1hcdOl6ZorYoSM2X1df97Ux-PLbnRPvSS

This one has more OIII data normally, 

Cheers,

Janos

Hi Mabula,

I have reprocessed Sh2-101 with bilinear interpolation in APP. The result was initially too blue and green, so I needed to tune these channels down. After that I achieved a better color balance I believe, see hier:  https://www.astrobin.com/354936/B/

Cheers,

Janos

Just to share the result of my last session yesterday evening: the Veil nebula complex with the STC filter. During processing I just kept default for the debayering algorithm, 

https://www.astrobin.com/355984/?nc=user

Cheers,

Janos

Posted by: Janos

Just to share the result of my last session yesterday evening: the Veil nebula complex with the STC filter. During processing I just kept default for the debayering algorithm, 

https://www.astrobin.com/355984/?nc=user

Cheers,

Janos

 

Hi Janos @jarbi58,

This looks very nice indeed 😉

I haven't had time yet, to look at your data, but I will in the upcoming days 😉

Mabula

Posted by: Mabula Haverkamp - Admin

Posted by: Janos

Just to share the result of my last session yesterday evening: the Veil nebula complex with the STC filter. During processing I just kept default for the debayering algorithm, 

https://www.astrobin.com/355984/?nc=user

Cheers,

Janos

 

Hi Janos @jarbi58,

This looks very nice indeed 😉

I haven't had time yet, to look at your data, but I will in the upcoming days 😉

Mabula

Thanks Mabula,

I'm looking forward to read your findings 😉

Cheers,

Janos

Hi Janos @jarbi58,

It took some time, but I am now working an a special debayer option in APP for STC DUO filter data. I downloaded your NGC7000  and SH2-101 data and I received more data from Anne van Houwelingen @annehouw as well.

I'll keep you updated on my progress 😉

Mabula

Posted by: Mabula Haverkamp - Admin

Hi Janos @jarbi58,

It took some time, but I am now working an a special debayer option in APP for STC DUO filter data. I downloaded your NGC7000  and SH2-101 data and I received more data from Anne van Houwelingen @annehouw as well.

I'll keep you updated on my progress 😉

Mabula

Thanks Mabula,

I am looking forward to see the new option !

Hi Janos @jarbi58, Kross @kross and Anne @annehouw ,

I have implemented full support for these kind of filters, so-called Multiple Narrowband Filters.

I will soon release APP 1.068 with these new debayer algortihms. You can find all details here:

https://www.astropixelprocessor.com/community/release-information/astro-pixel-processor-1-068-preparing-next-release/

Thank you very much for providing me with test data 😉

Kind regards,

Mabula

Hello

reviving this thread as I have the same combo as you Janos (ASI071 and STC duo narrowband filter). New to APP, so it is surely a dumb question, but try as I may, I only get monochrome images (B&W), whatever debayer option I use (H-alpha OIII colour, or separate H-alpha and OIII extractions + RGB combine tool).

I have tried pattern option "supported" and RGGB (which is what I was using in DSS), not to avail. So I am a bit left scratching my head here. If one of you guys can point me in the right direction, it would be cool !

Thanks and CS

Adrien

Posted by: AdrienL

Hello

reviving this thread as I have the same combo as you Janos (ASI071 and STC duo narrowband filter). New to APP, so it is surely a dumb question, but try as I may, I only get monochrome images (B&W), whatever debayer option I use (H-alpha OIII colour, or separate H-alpha and OIII extractions + RGB combine tool).

I have tried pattern option "supported" and RGGB (which is what I was using in DSS), not to avail. So I am a bit left scratching my head here. If one of you guys can point me in the right direction, it would be cool !

Thanks and CS

Adrien

Hi Adrien,

You are maybe just one click away from the solution :-). When you select RGGB, you need to tick also the checkbox "force Bayer CFA". I hope this helps.

One more question just to be sure: you have shot all frames in RAW format I believe,

CS,

Janos

Adrien,

I forgot to mention: if you have the latest version of APP, choose debayering option "HA-OIII color", pattern "RGGB" and activate checkbox "force Bayer CFA" to get the best results with this filter,

CS,

Janos

Thanks so much Janos for the quick turn around ! I'll give it a go and report back.

kind regards

Adrien

I also have the STC dual NB filter.  One other trap to avoid - if you forget to check "Force Bayer CFA" the first time you run APP, it may produce master calibration frames (darks, flats, bias, BPM) that are not de-Bayered.  You should not use those master frames with de-Bayered light frames.   Delete them if you have them in your file list, and create new master calibration frames that are also de-Bayered with the "Force Bayer CFA" box checked.

Cheers,

Rowland

thanks Roland and Janos for the good tips. It did work!

I'll try next to do some extracts in Halpha and Oiii separetely and combine them to see how that compares. Cheers

Adrien

Is there anything available for a qua-band narrowband filter like the Opt Triad Ultra?

It has the following characteristics:

I've got very promising results using the STC DNB on Nikon D800a with APP (attached below) and would like to push the envelope even further... Any hints on how to approach quad narrowband on a CFA?

--Simon

Hello to all,

I need some help here please. My goal is to extract Ha and OIII and then recombine using the RGB tool to an HOO palette but I'm running into issues. I have read and tried the PDF document and the result is a mono image with a mosaic pattern to it which I assume is the bayer array. I've tried a few different things.

First, I my settings in TAB 0 like this, Pattern = Supported, Algo= Ha-Oiii extract Ha

I then proceed to all other TABs and  enter the setting, but for this I used defaults as a test. I integrate and I get a mono image with a mosaic. I then go to the TAB 0 again and extract OIII and again I get a mono image with a mosaic pattern.

When I combine in TAB 9 RGB and assign R=Ha G=OIII and B=OIII I get this, a mono image with a mosaic pattern.

Now I tried the normal force CFA and it works. I get a demosaic color image. I've tried to use debayered FLATS and I get this warning,

I've looked around the site for a tutorial and I came up with nothing, probably missed it. So if someone can shed some light on what I'm missing I'd appreciate it.

Forgive me if this was addressed somewhere else, I've been looking everywhere to no avail.

TIA,

Roberto

PS Equipment used was STC Duo Narrowband and ASI071 Pro.

I think I found the answer. I'll try it. Thanks

Could you share what you found out? 🙂

Yes Sir,

I found this under Forum>Totorial and Workflows. It’s for an L-enhance but that filter to what I understand is very close to the STC Duo Narrowband.

https://www.astropixelprocessor.com/community/tutorials-workflows/combining-r-g-b-with-ha-oiii-data-using-an-optolong-l-enhance-filter/