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OSC and Tri-Band Filter
I have just acquired an ASI294MC-Pro and fitted it with an Optolong L-eNhance tri-band filter. Whilst I have some experience with astroimaging, this is my first OSC camera and also I am new to APP, so please bear with me.
I note that when setting up the RAW/FITS at the start, that for a 'standard' camera such as mine then Adaptive Airy Disc is used. I also note that the help tips say for narrow band use the appropriate setting. This is where I am confused.
Which is the best setting to use when images are taken with OSC fitted with tri-band?
First of all, welcome! And thanks for choosing APP.
So, the Optolong filter is a duo-band only right? Ha and OIII. You will probably need to check the "Force CFA" and pick one of the Ha-OIII options. The color option will produce a combined image just like it is. The others will seperate the Ha and OIII for you to be able to work on before combining later.
Thanks for the reply and the advice - just what I needed.
I realise that this filter is actually two-channel/duo band. I used the term tri-band only because several manufacturers use that description e.g. Altair Astro. I think they call it tri- because one channel covers Ha and the other covers both OIII and Hb.
(I'm looking at buying the asi294mc-pro.) Can you tell me why there needs to be an Ha-OIII selection? Why couldn't the images be processed like a normal CFA, and why do narrow band images need a selection? Can't they just be processed as monochrome or is it just for labeling?
You can just go for monochrome only yes (it's one of the options in the menu). It's all about choice, you can select Ha-OIII color to just get a color integration as-is, you can go mono which combines the data into one monochrome stack and you can seperate the channels. This can be nice as OIII tends to be weaker for instance and by boosting that separately, you can change the outcome in the end. It gives more control basically. Ha-OIII color might be the same as just a normal CFA and it would then just be the label indeed, not 100% sure, but I think that's the case.
I have the Triad Quad filter - is there any way to be able to do the extraction on 3 channels using APP? Ha/Hb, SII, OIII?
There is a h-beta option as well yes
I have been having a hard time pulling much color from my Bortle 8 skies and have considered the Optolong L-enhance filter. Did not realize APP would split out the HA and Oiii data. Wondered who else might be using this to get better color with OSC cameras in light polluted skies.
Well, for true color you still need broadband data. With narrowband you get much better signal in polluted skies, but you miss most of a normal spectrum. So you can get any color you want by combining these narrowband images, but if you're looking for nice orange and blue stars etc, you still would need regular R,G and B as well.
Would it be feasible to take a series of images with the filter which give me the HA ans OIII along with normal OSC (RGB) and combine all the data in APP?
In my last effort I just noticed "force Bayer/X-Trans CFA, used it and was able to take process this image. I will use it as a base line for experimentation with the New Filters.
Yes, you can combine regular RGB with narrowband, but only when you make the regular RGB, single channel first. You do this by using the "split channels" option in tab 2 all the way down. First calibrate the RGB and then split the channels. Load those in again together with the narrowband data and process.
Sorry Vincent, I am a little dense on this subject.
What I am hearing is that I would I load all the lights, darks, flats and dark flats, then choose split and Save Calibrated Files to give me three sets of files in R,G and B.
Next select the correct algorithm (Ha - OIII Color) then load the filtered images, darks, flats and Dark Flats select. Then do I simply add the already calibrated Red, Green and Blue files previously saved?
No problem, ask away. 🙂
Here is a workflow that works for many; https://www.astropixelprocessor.com/community/postid/7610/
If anything is unclear there, please ask, happy to help.