Open Heart Surgery

[Bob Andersson]

Hi folks,

Sometimes stars just get in the way...

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8 x 1500 seconds of 3nm Hα via a TEC 140 plus ML16803. Apart from star removal and noise reduction the image is essentially as delivered from PixInsight with minimal extra processing. Further manipulation of the 4096 x 4096 pixel original (using LHE for example) is revealing lots of structure but I'm finding blending the various intermediate images into a final rendition tricky and that's even before adding in some separately exposed RGB stars.

For those who haven't guessed what it is the clue is in the title...

Bob.

[fredster]

Incredible! Awesome Bob

[DirkSteele]

That is an incredible image. Thanks for sharing.

Clear skies,

[Ganymede12]

Amazing detail!

Who needs stars?

[Mark72]

Bob,

I think with such amount of signal you can try deconvolution in PixInsight though it's hit and miss

Mark

[Gina]

Well there's certainly no stars And great detail

[Ganymede12]

Why aren't there any stars in this picture? Is the gas oblique and light can't get through?

[paul schofield]

Absolutely lovely image.

[Bob Andersson]

Why aren't there any stars in this picture? ...

I removed 'em! It's part of my normal workflow for this type of image. I take the Hα stars away which leaves me much more latitude for processing the nebulosity without the stars creating artefacts (ringing). And then add a more representative selection of stars from separately exposed RGB subs towards the end after adding colour to the nebulosity as desired.

But stars really do get in the way sometimes. For this image I manually removed the stars (rather than cleaning up after a more automated process) and it's amazing how structure that wasn't easily seen just leaps out as one proceeds - very therapeutic. If anyone ever invents an f/0.001 lens of sufficient focal length they'd make a fortune as the exposure time for the nebulosity would be so short there wouldn't be enough light to capture any stars anyway!!!

Bob.

[sologuitarist61]

Superb image Bob

[farunj]

That's stunning!! Wow!!

[Bob Andersson]

Bob,

I think with such amount of signal you can try deconvolution in PixInsight though it's hit and miss

Mark

Hi Mark,

Good call - I usually only think of deconvolution for stars. I've just done a pass with the default PI settings and the effect is subtle but worthwhile, with edges crisping up slightly and no black artefacts to speak of, and varying those settings didn't improve things any. The remnants of the faint stars that I hadn't removed do show up a little more but I should be able to leave those be as the RGB stars should mask them and I think that that route plus a little manual clean-up will be more successful than trying to use PI to mask such faint stars. Thanks for the tip.

Bob.