For combining channels I simply used LRGB combination, with Ha being Lum. I was hoping to add at least OIII to Lum, but it has way too much noise with just 7hrs of integration, so I just used straight Ha for Lum.
For combining channels I simply used LRGB combination, with Ha being Lum. I was hoping to add at least OIII to Lum, but it has way too much noise with just 7hrs of integration, so I just used straight Ha for Lum.
Hi Suavi,
If you combine the Ha, Oiii and Sii using ImageIntegration (noise-weighted, no rejection) you should get a SNR improvement and also a contribution to the Lum from the other filters, though it may be small if those masters are very noisy compared to the Ha. Worth a try if you haven't attempted it before.
If you combine the Ha, Oiii and Sii using ImageIntegration (noise-weighted, no rejection) you should get a SNR improvement and also a contribution to the Lum from the other filters, though it may be small if those masters are very noisy compared to the Ha. Worth a try if you haven't attempted it before.
Cheers,
Rick.
Great advice, thank you Rick. I will certainly try it.
Signal in OIII is around 300 ADUs above the floor in the brightest areas, while SII is only about 250 ADUs in the same regions, while Ha is nearly 2000ADUs (Gain =0.16). I would also like to try making RGBish stars from narrowband data I have. Will report soon, I hope :-)
Given that my camera decided to fog up (first time for me!), I am out of action tonight, or so it seems!
Tried Rick's advice of using Image Integration to combine all subs and it works wonderfully, at least I believe it does
I have attached three screen shots of different areas in the Lum image. The one on the left is a result of ImageIntegration (Ha+OIII+SII) without pixel rejection, the middle one is with rejection (love those planes and satellites!), and the one on the right is just Ha that I originally used for Lum (but not drizzled).
I also selected a small section in all three and measured StDev. In all cases, for the combined subs (HA+OIII+SII), StDev was about half of what I was getting in Ha only.
Me think it's time to reprocess my image...thank you Rick!
Beautiful region Slawomir. I like the way you have captured that background nebulosity as well (upper left). I think that background shows the vastness of the nebula.
Thank you Brett. As I am gaining more experience with using this scope, I like it more and more. My next image will be at f/6 with a dedicated flattener. It generates perfectly flat field and round stars to the corners, and it won't require as frequent refocusing as imaging at f/4.5 with Riccardi reducer. With the Riccardi I must refocus every 1 degree.
Quote:
Originally Posted by Atmos
Prefer the slightly redder new version
Me too I have been tweaking colours a few times since I produced this latest revision, but somehow I keep coming back to this one. It's a sign to move onto a new project.
If I might chime in regarding "super-lum" combination; it's worth trying to integrate all Ha subs into one master (with rejection), all SII into another master (also with rejection), same for OIII. Then using those masters, integrate them using ImageIntegration with no rejection. This gets rid of satellite trails and FPN (if you've dithered), while giving you a higher SNR "super-lum" master in the end. I think this is what Rick was suggesting, but I think from your post above you simply integrated all the subs together.
You might want to play around with noise-weighted vs "don't care (all weights = 1)" as well. Noise-weighted will heavily favour Ha in most integrations, giving you a lower noise image but without much of the detail from SII / OIII, while "all weights = 1" will bring in more of the detail from the others at the expense of more noise.
You could also play around with PixelMath to integrate the masters easily with a higher degree of flexibility regarding the weighting.
Thank you Lee and Colin for your very good suggestions
Initially, when putting the data together for the first time, I did exactly what Colin recommended. However, OIII and SII masters were/are very noisy comparing to Ha (signal was 6 and 8 times weaker respectively, and OIII had the highest noise). Thus combining the masters did make the Lum image significantly more noisy, so I decided against this method. In fact, I tried adding noise-reduced OIII and SII and I still felt that the result was inferior.
Using image integration for all subs somehow increased detail in the Lum, perhaps because I had only 13 Ha subs and 56 subs for OIII and SII altogether (no somos machos pero somos muchos).
The final image (revision E) is a blend of 50% Revision D (Ha Lum) and 50% Revision X (Lum=Image integration on all subs).
Simply outstanding image Sauvi. I'm particularly impressed how far you can zoom into the full res and more and more detail comes out - almost like what you expect from a mosaic.
I guess we're seeing the benefits of lots of data, great tracking (and optics), careful processing including drizzle to give an effectively 2x2 larger image.
Whatever, its simply inspiring stuff to see an 8300 sensor in the burbs performing this well. (I like it by the way )
)
