IC 405 (also known as the Flaming Star Nebula, SH 2-229, or Caldwell 31) is an emission and reflection nebula in the constellation Auriga north of the celestial equator, surrounding the bluish, irregular variable star AE Aurigae. It shines at magnitude +6.0.
The nebula measures approximately 37.0' x 19.0', and lies about 1,500 light-years away from Earth. It is believed that the proper motion of the central star can be traced back to the Orion's Belt area. The nebula is about 5 light-years across.
https://en.wikipedia.org/wiki/IC_405Rippling dust and gas lanes give the Flaming Star Nebula its name. The orange and purple colors of the nebula are present in different regions and are created by different processes. The bright star AE Aurigae, visible toward the image left, is so hot it is blue, emitting light so energetic it knocks electrons away from surrounding gas. When a proton recaptures an electron, red light is frequently emitted (depicted here in orange). The purple region's color is a mix of this red light and blue light emitted by AE Aurigae but reflected to us by surrounding dust. The two regions are referred to as emission nebula and reflection nebula, respectively. Pictured here in the Hubble color palette, the Flaming Star Nebula, officially known as IC 405, lies about 1500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of the Charioteer (Auriga).
https://science.nasa.gov/ic-405-flaming-star-nebula--------------------------------------------------------------------------------------------------
Finally after almost a month and a half I was able to conclude the development of this project. It is one of those projects where several times I had to restart its processing from scratch since I did not like the final result both in the details and the resulting coloration.
Of course, in my particular way of developing my work, what I do is complicate my life more instead of making it more fluid... one day I will learn to focus on the latter.
Since we knowed about this nebula we caught fascinated of its beauty and the particular aspect that is an emission and a reflection nebula at the same time due its special area where is evolving and the star that produce those effects in its nebulae. Maurizio conducted the sessions of this nebula in January, February and November 2021, January 2022 and other in January 2023 from our backyard and in a mountain location.
In January of this year I did a quick review and test of this nebula and I found an interesting situation in the details of the reflection of the nebula present in the stack made with the L-Pro filter but absent in the stack of L-Extreme and Triad-Ultra filter.
For this reason, I asked Maurizio for an extra L-Pro session, which he did immediately, since the sessions done with L-Pro in January 2022 were very limited to the central area of the nebula (on that occasion he also did two other sessions to the half right and left). of the nebula with the intention of making a base mosaic of stars (but it was difficult to combine and without the expected results so in the end was discarded) I wanted to have better information on the nebula with this filter because I actually wanted to assemble it later with the other stacks of the band filters.
In the following starless images you can clearly see the area reflected by the class O9 star HD34078 AE Aurigae in the stack with the L-Pro filter on the right, which is a filter for avoid light pollution of a certain type and its incidence is almost non-existent in mountainous areas or with Bortle 4 as it was done, (therefore it is as if I took it without filters) with respect to duo-band filters like the L- Extreme and quad-band as Triad-Ultra, image on the left. Very peculiar is the 'hazy reflection' on the right indicated by the lower right arrow in L-Pro, but absent in the band stack.
Doing an extensive review in Astrobin I did not find that peculiarity 'haze' since the vast majority of the images are in SHO or HOO and those that are not, I didn't saw it but also is due several reasons I observed in there. It should be noted that both in the January 2022 session and the one carried out in January 2023, that 'haze reflection' appears in both stacks, for which I ruled out the product of dirt on the telescope lens or the camera sensor or the filter.
So once the star base stack was made with the L-Pro filter in DSS, I proceeded to stack the sessions made with Extreme and Triad-Ultra together. It resulted in a very beautiful image and rich in information of its Ha composition.
Then I performed the extraction of Ha and [OIII] with Siril to compose a SHO type image. Once the results were obtained, seeing the extraction of Ha only made me incredibly excited. I still use the previous version of Siril, but this time I dared to apply both the Histogram Transformation and the Generalized Hyperbolic Transformation on both stacks and the result was amazing. The GHT gives an extraordinary value to the middle zone of contrast that makes a noticeable difference and brings out the details of the nebula.
The SHO image was composited R= Ha G= Ha 0.3 + [OIII]0.7 and B=[OIII] then in CamRaw I used Hue to adjust the tones of the resulting image.
The hard part was combining a final solution between the reflection details of L-Pro, the regular Extreme-Triad stack, and the SHO-like composite image. I ended up using an extra combination of layers of each final stacks with different types of blend. This almost cost me two weeks of trying. In fact, I had to let a few days go by to see the image again and make the adjustments that I thought most convenient until I found not only the percentages but also the appropriate blend that reflected all the information contained in the different stacks made.
The other equally difficult part was properly exposing the visualization of stars. The area where the Flaming Star Nebula is located is densely populated with stars and finding a viable relationship that does not distract the view of the nebula and its details from the starry background is not easy. I believe, however, that I have reached a satisfactory compromise in this regard.
We appreciate your visit and we wish you all Clear Skies.
Processed April 2023.
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