NGC 2174 "Monkey Head Nebula" in bi-color

[antimorris]

This is my first bicolor (Ha + OIII) narrowband image. Normally I just leave Ha as B&W, but finally got an OIII filter so off I go into color narrowband imaging. This is only 6 hrs of data (3hrs Ha, 3hrs OIII), I do hope to get more soon though the forecast isn't promising so I went ahead and processed.

After a few days of trying I think I have a method (albeit convoluted) that gets a result I like. Basically I have combined portions of all the various bicolor processing techniques I found. A little of Cannistra's, a little of JPM's tone-mapping, a little of my own mixture and PS actions and alot of layers and masks. For only 6 hrs of data (3hrs each of Ha and OIII) I think I have pulled out a good bit of detail and data, at least enough to make make me happy. I also found a balance of colors that I like (although I know with NB this is basically personal preference).

Here is the full frame:

and a crop of the region I have been focusing on getting some depth to to look more 3D than flat:

I am quite please with it so far (for my first bicolor NB image) and am looking forward to getting more data and trying it on more objects. What do you think about it?

[davew]

Hi Anna,

That I really like. You've got a colour result that's very pleasing. When I do it the Ha looks red and the O111 very creamy. I think I'll have a look at the authors you mention.

You've brought the dust " Forward " beautifully.

Dave.

[MartinB]

That is an amazing 2 colour process. The colour is superb as is the image as a whole. I would love to hear more about how you did this

[antimorris]

Martin - I will write up something here in a bit about how I processed it and post it here. As I said, it was a bit of a convoluted process and mixture of various techniques (aka time consuming), but I think it was worth it.

[antimorris]

I started to write up my processing of this and realized that since I used several combined methods it was going to get a little long. Would you like the whole long version Martin or just a synopsis?

[swag72]

That is a stunning image, and using NB and OIII makes me wonder whether that is doable with a DSLR. I would love to know how you achieved this please!!

[Coco]

OOohh... I like that

very nice ..

[TakMan]

Love the colours - very vibrant...

Awaiting the processing write-up with interest!

Clear skies,

Damian

[RogerTheDodger]

Really nice image, the colours look beautiful.

[antimorris]

I used quite a variety of techniques and other tools for processing this. All of which I did in Photoshop CS2. I’ll start from the beginning and give the general gist. I apologize now if this gets a little long but I have gotten several people asking so would like to share as best I can.

From my calibrated stacks of Ha and OIII I ran through my normal processing workflow on each. To sum that up, basically levels, curves (both in many iterations), run-through of my action sets (mainly channel processing and enhance galaxy detail), then a high pass overlay layer (mild – usually around .6-.8). Then a few more curves and levels as needed. I did not do any noise reduction at this point. From here is where it branches off a bit. I basically did 3 different variations of bicolor processing and then used masks and layers to combine then. The first I did was Cannistra’s bicolor technique (located here: Cannistra Bicolor Narrowband Technique) … After finished I used the “selective color” as a layer and adjusted to my liking. This provided an ok result but was a bit anemic in color overall. Saved this then on to the next method.

Method 2 which required me to create my own synthetic green channel (as I used the Ha for red and the OIII for blue). To do this I combined them using “Apply Image” and applied the Ha over the OIII. I tinkered a bit with the settings to not overpower one with the other but I think I settled on Adding the Ha at 80% opacity as a mask. I then just copied the Ha to the red channel, my Syn Green to green, and my OIII to blue, balanced the background and channels and saved it. This one was very yellow, but had some nice details in areas that the other variation didn’t.

The 3rd method was JPM’s tone-mapping (Astro Anarchy: The power of Tone Mapping). Using the same syn-green I ran through his whole tutorial and saved. This method was more time-intensive than the others but provided a fairly decent recent. I liked the color (although I did up the saturation a little and used “selective color” some to bring out a little more depth to the image) and detail was alright, though not as good, oddly enough, as my “yellow” version. Now on to combining them.

I started with my Yellow version as a base, pasted the anemic 1st version as a layer with blending method set to darken. This enhanced some of the finer details a little. Merged those down. Then I opened up the tone-mapped version. I “added” this in Apply image to the pervious merged image. I had to play with the amount and opacities here to get a look I liked. This resulted in close to the details I wanted, but had a mix of the decent color and the yellow so I then pasted the tone-mapped one over the result and blended it as “color”. A few finishing touches (another enhance galaxy trails action play, some mild noise reduction with NoiseNinja, and another round of levels and saturation masks) and voila.

Probably not the most straight-forward of methods to be sure, but for my first bicolor I was happy with the result and although I am sure I will do some fine-tuning of my process for this in the future, it will probably continue to resemble this.

[MartinB]

Thanks Anna, I'll have a look at this using some of my own data. Will be interested to see how an Ha OIII and an HST can compare.

[peter shah]

a superb shot showing great colour and detail....lovely!