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Keeping the details of a single frame in the final stack

Processing Stacking Deep Sky Meteor
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Christian Bennich avatar
Christian Bennich avatar
Hey

I have been fortunate enough to catch a meteor in a single Luminance frame among hundreds on the DSO I'm currently working on. 

I am imaging at 250mm with an ASI2600MM, and drizzle x 2 as part of my flow. 

When I go through ImageIntegration, my beautiful meteor is naturally rejected as a satellite trail or something, so it's gone in my final stack . 

How could I go about keeping my meteor in the final stack?

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Francesco Meschia avatar
Francesco Meschia avatar
Since it's just one frame, I would manually add it with PixelMath. I would first normalize the single calibrated and registered sub so that it has the same median value as the stack, then I'd do something like "stack + max(stack, single)". Probably with a mask to avoid adding noise too the entire frame.
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andrea tasselli avatar
andrea tasselli avatar
PixelMath, as Francesco has described above. Better still, remove the stars from both the stack and the single shot (after calibration and LinearFit applied to the meteor shot using the final stack as the reference ) and then proceed with the expression given above.

Incidentally, this one of those cases where having had an OSC camera would have been a bonus…
Christian Bennich avatar
Christian Bennich avatar
andrea tasselli:
PixelMath, as Francesco has described above. Better still, remove the stars from both the stack and the single shot (after calibration and LinearFit applied to the meteor shot using the final stack as the reference ) and then proceed with the expression given above.

Incidentally, this one of those cases where having had an OSC camera would have been a bonus...

HAHAHAA - True that
Christian Bennich avatar
Christian Bennich avatar
But when I drizzle the images, the image "grows," which means if I use the registered image, it will no longer have the same proportions as the drizzled one—will it?
Francesco Meschia avatar
Francesco Meschia avatar
No it won't. You'll have to up-sample the single frame.
Christian Bennich avatar
Christian Bennich avatar
Ah, yeah!!

Thx!
Wei-Hao Wang avatar
Wei-Hao Wang avatar
Let me add one thing to the workflow suggested by Francesco and Andrea: run an aggressive noise reduction (NXT for example) on that single frame before the pixel math.  This prevents noise in that single frame to be added.

If you use Photoshop, it is possible to just do the adding around the area of the meteor.  But it looks like this kind of operation is not favored (or even not allowed) in PI.
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Brian Poole avatar
Brian Poole avatar
I have nothing to add, but that's a great capture and I look forward to seeing the results.
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