Deconvolution Process Settings

[niteman1946]

Hi Group,

My standard approach with DeCon is to apply a luminance mask, reference a star mask, create an external PSF, and (usually) set Global Dark (under Deringing) to 0.005.  And run 50 iterations.  Works fine, I'm happy.

Every so often, in addition to the above, I select Parametric PSF and reduce Std Dev a bit to further suppress ringing.  I've assumed that by doing this the External and Parametric PSFs were working hand-in-hand.

But is this true?  When I select the Parametric tab does the setup then ignore data from the External PSF?

Also, if that is true, I'm wondering why not use the Parametric all (most?) of the time.  This would save manually creating the PSF.

Appreciate your comments,

Mark

[Carlos Milovic]

Hi Mark
No, they don't work han-in-hand. The PSF method currently selected by the tab selector is the one that is used.

We rather use the external PSF because it may fit better the real data. In some cases, specially when the PSF varies across the image, a parametric PSF may yield better results, but in most cases, using the stars as models is better (after all, they are pinpoint sources, so it is a perfect "point spread function").

[niteman1946]

Thanks Carlos,

It's what I expected once I gave it some thought.

Then when using External PSF, would increasing Global Dark be your recommendation to dampen down problematic ringing?

Mark

[niteman1946]

Then when using External PSF, would increasing Global Dark be your recommendation to dampen down problematic ringing?

I should have qualified "for stars imbedded in nebulosity".  And answering my on question, it appears to be "yes".

Mark

[Carlos Milovic]

Yes, increase it. Anyway, try always to keep it as low as possible. Increase with care. Also, consider refining your masks, and local ringing support.