I have a Zwo 533MC Pro and a L-extreme dual narrowband filter. I’m working on a project where I have about 20 hours of broadband data for M51 and 30 hours of narrowband data also for M51. I want to combine the detail and all the Ha data that I was able to collect with the narrowband filter with the broadband data of the galaxy. I have searched around for videos and most of them are dealing with mono cameras. Does anyone have any tips on the best way to combine this data? Or have any direction they could point me to so I can learn more. Thanks for any help!
Combining OSC data with dual narrowband data
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The L-Extreme data isn't pure Ha or pure OIII but that and also the broadband signal that is also captured. Blending the two might be a mix of several things, notably straight addition of both images (NB and RGB) once normalized to each other, scaled addition of the same using SNR as weight or selective blending of the NB R channel into the R channel from the RGB image and potentially also the G channel from the NB into the G/B channels of the RGB image. You might either add or XOR one channel into another once they are both normalized to each other. As an example here is one blend:
M51 NB+RGB (OSC) 2in1 - AstroBin
M51 NB+RGB (OSC) 2in1 - AstroBin
andrea tasselli:
The L-Extreme data isn't pure Ha or pure OIII but that and also the broadband signal that is also captured. Blending the two might be a mix of several things, notably straight addition of both images (NB and RGB) once normalized to each other, scaled addition of the same using SNR as weight or selective blending of the NB R channel into the R channel from the RGB image and potentially also the G channel from the NB into the G/B channels of the RGB image. You might either add or XOR one channel into another once they are both normalized to each other. As an example here is one blend:
M51 NB+RGB (OSC) 2in1 - AstroBin
Thank you for the reply! What would be the process to do this? I have tried combining images before stretching, after stretching, combining individual split channels then back to rgb, and have tried a few scripts for combining narrowband data with rgb. How would I normalize the images to each other? I have been doing spcc to each before combining them.
What are you using for processing?
andrea tasselli:
What are you using for processing?
I am using Pixinsight for everything.
Good. You can either blend in the linear phase or after stretching, it's a matter of preferences. Normalization means using LinearFit using a reference image (e.g. the RGB R channel) to which the other channel is added (or XOR-ed), such as the R NB channel. Or you can add them together in PixelMath (such as (A+B)*0.5). If you want to add them using the SNR as weight the this needs to be done in the linear phase only using ImageIntegration. Once you have combined them (in the linear phase) you'll be well advised to use ColorCalibration to rebalance the final RGB composite.
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