M42 - LRGB

[rodmichael]

This is my first attempt at M42 (10th month of AP). Image pre- and post-processed in PixInsight.

I used 240 total subframes, 120 at 150s (30 each LRGB) and 120 at 30s.

Imaging System = Celestron 11" RASA, f2.22; QSI683WS; Astrodon Gen2 LRGB filters; SB Paramount MX+ with TPoint Supermodel. Otherwise unguided.

I attempted to do HDR composition to account for overexposure of nebula core. I combined stacked linear RGB images of 30s and 150s to produce a linear HDR RGB image. I did the same thing with the Luminance images (20s and 150s).

I stretched the HDR RGB and Luminance images, each in 2 passes.

I did an LRGB combination using a Luminance Transfer Factor of 50 and a Chrominance Transfer Factor of 40.

I performed Noise Reduction with SCNR (Green) and ACDNR.

All comments, critique, or suggestions welcome.

[rodmichael]

I think I made a major improvement to the image in an attempt to reduce the brightness of the core.

I went back and simply applied HDRMultiscale Transformation (HDRMT) to the HDR Luminance frame, 6-layers, 1 iteration. This is what I came up with after LRGB combination (no HDRMT to HDR RGB frame). This seems like my very best image of M42 so far.

In addition to having a very clear view of the Trapezium stars, the depth of the nebular structure seems to be much enhanced. And the "skeletal" appearance (as I call it) in some renditions doesn't seem as apparent or overwhelming. A personal taste thing, I suppose.

[ChoJin]

Hello,

congrats Michael. This target really is a wonder.

I don't have any experience with this target, but did you try/apply deconvolution (after integration and DBE, while still linear)?

NB: it seems to me that your mirrors might benefit from some collimation?

[rodmichael]

Hello,

congrats Michael. This target really is a wonder.

I don't have any experience with this target, but did you try/apply deconvolution (after integration and DBE, while still linear)?

NB: it seems to me that your mirrors might benefit from some collimation?

No, I've thought about deconvolution, but my limited experience tells me that deconvolution is usually not a very useful tool, at least for me. I'm guessing that you find my stars a bit bloated (so do I). I haven't really got into star reduction yet. I will probably have to bite the bullet one of these days and start learning those processes that can help with that.

Please tell me what you see that suggests a collimation issue. I've been wondering about that myself.

Thanks!

[ChoJin]

for the deconvolution, I thought it could bring more details to the nebulosity. I usually don't mind that much about bloated stars unlike most ppl on this forum ;-)

for the collimation, i'm just curious about why the blooms on medium-sized stars seem to be mostly oriented upward instead of being circular.