One of the first targets I chose for my newly arrived Dual Narrowband filter. Since this was my home state, I wanted to do this justice as well as collect a large amount of data. Included is 16 hours+ of integration from my backyard with a Dual Ha Oiii filter in false color with an orange for red/Ha and blue-green for "Oiii".

Since I had never heard of this nebula (funnily enough) until I started imaging, I had to do some reading.  The nebula is most likely excited by the energy from Menkib (xi Persei in the top right of the image). It is very red in OSC and prominently emits in Hydrogen alpha wavelengths. According to an article from Observing at Skyhound, the nebula is also visible in Hydrogen beta. I'm really excited to come back and add another 16 hours of data when my Sii - Hb dual band filter comes in.

On another note, Menkib (the kinda odd looking bright star), is a very interesting star in its own right. It is an O type Blue giant and it is a runaway star. 

Currently (2024/01/08), this image is composed of 320x180s Dual Narrowband Ha Oiii stacked in ASTAP. The resulting stack was processed in Affinity Photo 2. This time around, I took a different approach to editing. I split the channels apart into R, G, B from the debayered stacked image and worked to edit them separately. This was in the hope that I could bring out more of the Oiii signal. In reality, there does not seem to be much Oiii coming from this nebula so the G and B layers ended up adding noise to the overall image and more Ha. The three colors were stretched in monochrome independently. I then combined the Green and Blue channels (after I colored them) 0.5 green to 1 blue to get a richer blue image. The red channel I colored vibrant orange with an end goal of getting gold when I combined the images using Add. 

After some further tweaks using curves, HSL shifting of saturation, and some background extraction in Affinity, I used Starnet 2 to remove the starts and I brought in some no filter stars from 7x300s no filter OSC image. This is notably the part that needs the most improvement as they look kind of odd. I'll need to add in more of this data later on. 

Overall, I'm pretty satisfied with the image. I managed to get the palette I was looking for (blue and gold) while learning a bunch about Dual NB and its uses and limitations with OSC. I'll need to work on overlaying no filter stars process and more accurate processing of DNB data in the next edit. I also cannot wait to add Hb and Sii data.

UPDATE: 2024/02/10

I managed to finally add in the Sii and Hb dual narrowband data as well as better blended "RGB" stars. I used the Antlia Quad-Band stars for this new revision since it seems to do a good job catching natural star colors. This took quite a while since I wanted a lot of data and it's been super rainy and cloudy till recently where we have a short break in the weather.

The process for this new addition and the revisions (I'm sorry if you are following me, I forgot to hit skip notify till the last revision was uploaded.) is as follows:

1. Clean and stack in ASTAP
2. GraXpert background removal for all included images (HaOiii, SiiHb, Quadband)
3. Bring images into Affinity
4. Get the stars
1. Levels and curves Quadband till satisfied then save as tiff 16bit
2. Run Starnet 2 and bring back the stars images
3. Noise reduction on stars to remove the Starnet 2 artifacts


5. Split the HaOiii and SiiHb images into their individual RGB channels.
6. Designate Ha -> R, Oiii -> G, Sii -> R, Hb -> G because the blue channels were much more noisy
7. Stretch channels individually as monochrome then export
8. Remove the stars in monochrome using Starnet 2 then bring the monochrome layers back to Affinity
9. Noise reduction, background removal/levelling, clarity filter each of the monochrome layers.
10. Recolor the layers and set blend modes
1. Ha -> 245, 0, 0
2. Sii -> 230, 0, 0
3. Oiii -> 0, 255, 146
4. Hb -> 0, 239, 255


11. Set a copy of monochrome Ha to Luminosity blend and set the rest to Add blend. Ha Luminosity crushes noise and brings out features.
12. Play around with layer combinations.
13. Channel mix to bring out the oranges in Sii and blues from Oiii and Hb.
14. Set stars to add