Flaming Star nebula C31/Ced42/LBN795/IC405/Sh2-229/VdB34 (c-shorgb)

[ramdom]

Total integration: 1303 minutes/21.7 hours (*42 x 300s for Ha + 24 x 300s for O3 + 42 x 300s for S2 + **109 x 420s for OSC).

Inline image uploaded to the forum. Full sized image is here: http://ram.org/images/space/scope/1.4+7.4.5+6/ic405_c_shorgb_42x300+24x300+42x300+109x420.jpg

Cameras: *QHY163M (16mp mono) and **QHY247C (24mp OSC) CMOS cooled to -20 and -15 degrees C.

Telescopes: *Takahashi FC100DF Steinheil fluorite doublet and **Stellarvue SV70T triplet apochromat refractors @ f/4.9 and @ f/4.8.

Reducers: *Takahashi FC-35 (0.66x) and SFFR70-APO (0.8x).

Mount: Paramount MyT.

Filters: 1.25" Astrodon 5nm Ha, 3nm O3, 3nm S2 and **2" Baader UV-IR-Cut

Software: TheSkyX Pro, Sharpcap, PixInsight.

The Flaming Star nebula (IC405) is fairly unique nebula in the constellation Auriga with obvious emission and reflection components. Specifically, there's this smoky wisp that is present in the centre of the nebula (see E, which is processed to highlight it). However, both components are due, either directly or indirectly (via dust), to the illumination of the bluish runaway star AE Aurigae.  It lies ~1500 light years away from Earth and is about five light years across.

https://www.astrobin.com/hrbn9j/A/ through https://www.astrobin.com/hrbn9j/D/ are combination images of the Flaming Star nebula consisting of both SHO data as well as RGB/OSC data (https://www.astrobin.com/hrbn9j/E/) and is still overall a work in progress with the goal of best highlighting that reflection smoky wisp against a background of emission signals as well as the creation of a largely widefield panorama. I initially wanted to create a two panel narrowband image of the IC405 and IC410 (Tadpoles) and then get more data for the OSC image that covers both in one panel in my SV70T and QHY247C but I attach what I have so far since I'm not sure if I'll be able finish it this year (I am also not happy with my framing of both these nebulae in my OSC and so will reshoot with a new framing and see if I can't merge the two datasets which will improve the OSC image).

The combined image is best appreciated in the context of my earlier narrowband images of IC405 which is available at: https://www.astrobin.com/318364/ with (A) Ha as well as (B,D) SHO and (D) HOS data along with the capture details (a total of 9 hours). These images were created with Photoshop CC which is not used here.

There's little O3 data for this target, so I used the blue channel to combine the G and B data from the OSC image, with my final combination looking like this:

R: S2 + R-OSC

G: Ha + R-OSC

B: O3 + G-OSC + B-OSC

I tried many different weighting schemes until I found a few that were okay and selected the best two (https://www.astrobin.com/hrbn9j/A/ and https://www.astrobin.com/hrbn9j/B/). For these, I did the combinations using PixelMath and rather than rescaling, I let it clip in blue so it looks saturated at the parts where the smoky bits overlaps with narrowband data. The narrowband image itself had some clipping since this was one of my first AP images and I wasn't sure what I was doing then.

In addition, based on feedback provided online, I tried another strategy using LRGB combination where I set the L channel to be the entire SHO data with the separated RGB images from the OSC data (https://www.astrobin.com/hrbn9j/C/ and https://www.astrobin.com/hrbn9j/D/) which produced my personal favourite (D). So there are many ways to skin the cat and I believe I will be coming back to this once I collect even more data and eventually do the two panel.

It seems like a lot of work but all I really want to is transpose that smoky bit from the OSC image onto the na<rrowband image I previously generated. It's not straight forward since I think perhaps there's some emission signal that can just be amplified (the smoky bit is where the S2, Ha, and O3 data most converge - so it's even arguable this image was necessary). But worst case, this also illustrates the difference between using Photoshop CC (which is what was done to generate the images on astrobin) vs. using PixInsight to do the Hubble palette tweaks.

As always, thanks for looking!

--Ram