Flaming Star Nebula in SHO

[windjammer]

Here is an SHO narrowband image of the Flaming Star Nebula, IC405 (SH2-229, LBN 795, vdB 34). The first image is a side by side comparison of the SHO product with an HS bicolour image I posted a week ago.  The Oiii signal has not added a lot.  The second image is a close up crop comparison of the brighter portions of the nebula.  Third image is a panel of the separate S, H and O master lights - the O light is pretty marginal. And there is definitely a dragon lurking in the Flaming Star which I don't want to look at any more.  Fourth image is an annotated set of various blends.

The Foraxx Palette utility in PI didn't work too well sorting out the colour mix on the SHO, so it was rendered instead by hand following the usual Hubble palette Selective Colour recipe.  Not entirely satisfactory - the Oiii signal is very weak and I think throws the whole thing off.  I have spent ages trying to get it to look sensible, but it is stuck in a hole. So time to move on!  Exposures, rig and processing details at the end fyi.

Simon

1. SHO product vs HS bicolour image

 

2. Close crop comparison

3. S, H and O master lights

 

4. Annotated set of various blends

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Data taken in Astronomik narrowband filters: Ha (656nm), Sii (672nm), Oiii (501nm). Total exposure time 12.8 hrs.

Ha 1x1 bin - 24x 600s = 4hrs, 14-15 October, seeing 2.0", scope West side, prime focus
Sii 1x1 bin - 27x 600s = 4.5hrs, 16-16 October, seeing 2.3", scope West side, prime focus
Oiii 1x1 bin - 26x 600s = 4.3hrs, 22-23 October, seeing 1.7", scope West side, prime focus

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Master Lights:
FWHM (pxl)    pre BXT        post BXT
Ha        2.810        1.644
Sii        2.728        1.603
Oiii        2.752        2.047

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Plate solver:
Resolution ............... 1.247 arcsec/px
Focal distance ........... 750.67 mm
Pixel size ............... 4.54 um
Field of view ............ 41' 44.9" x 32' 22.3"
Image center ............. RA:  5 16 31.716  Dec: +34 24 49.52
Image bounds:
   top-left .............. RA:  5 14 51.198  Dec: +34 41 14.15
   top-right ............. RA:  5 18 14.245  Dec: +34 40 41.87
   bottom-left ........... RA:  5 14 49.836  Dec: +34 08 51.87
   bottom-right .......... RA:  5 18 11.578  Dec: +34 08 19.79

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Rig:
Imaging scope: SW Startravel 150mm F5 Refractor, Baader Diamond Track, (2.5x Celestron Luminos 2inch imaging barlow), Atik 460EX mono

Guide scope: SW Evostar 90mm F10, with guiding XY stage, ZWO 120MM camera

Guiding: 2 stage PHD: high frequency guide scope (mount tracking) and low frequency OAG image train guiding (guidescope flex)

Mount: Home made German Equatorial pillow block mount, permanently rooftop mounted.  Spring loaded DEC axis gearing.

Other gadgets: ST4 based anti vibration shutter, ST4 based PEC

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Processing Lights:
PixInsight: Lights, Darks, Flats, Biases: master dark/dark library-> masterbias-> superbias-> calibrated flats-> master flat-> calibrated lights-> cosmetic correction-> aligned lights-> master light-> BXT

PixInsight: Master BXT lights-> crop-> linfit-> final master lights

PixInsight: final master lights->StarNet2 starless-> RGB Channel Combination (SHO)-> export xisf starless master.

GradXpert Gradient removal:->import starless xisf-> GXPT(20pc,3sg)-> export xisf, fits 

Affinity Photo 32 bit image processing:-> import SHO gxpt starless fits-> accept default stretch-> curves-> lvl(master)-> paint (cosmetic star haloes) ->Topaz Denoise(LL, 29, 27)-> Tpzdn(ST,4,24)-> Tpzdn(ST,4,7) -> lvl(master black pt) -> shadows/highlights -> HSO Selective Colour (http://bf-astro.com/hubblep.htm) -> Gaussian Blur(0.8pxl, 50%)

Affinity Photo final tart ups:-> paste in star mask layer, blend mode 'screen'

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Processing Star Mask:
PixInsight: final master lights-> RGB Channel Combination (SHO)-> StarNet2 star mask-> export fits starmask

Affinity Photo 32 bit image processing:-> import SHO starmask fits-> accept default stretch-> Auto Levels-> Defringe-> Auto Colour-> Auto White Balance-> vibrance-> manual white balance-> Selective Colour (black points)-> Gaussian Blur(0.1)-> paste Star Mask layer on top of starless final (blend mode 'screen')-> vibrance-> curves-> Gaussian Blur(0.1). 

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