Author Topic: (HA-R)GB  (Read 973 times)

Offline rmaddy

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(HA-R)GB
« on: 2017 November 23 13:12:02 »
I've been working with Vincent's scripts for HA-R combination.  Generally, I think they do much to improve the red channel, but the effect seems to "get away from me".  In other words, I end up with overly enhanced HA.  I have used the formulae as given, swapping in 70 and 5 for the values in the first equation (Astrodon 5nm), then widely tinkered from there, going off of visual effect for the most part.  In the second equation, I have tried a variety of constants, but for the most part, I'm just winging it while looking for results. 

Can anyone provide more consistent guidance?  These equations definitely solve the salmon colored wash out that is typical of straight HA/R combination.

Offline Greg Schwimer

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Re: (HA-R)GB
« Reply #1 on: 2017 November 23 21:48:48 »
I'm working through the same process myself right now on an image. The object is a bit different but variations of the equation are yielding great results.

I found that being very light on the multiplier (n)  in the 2nd pixel math equation ( $T + (ha - med(ha) * n) )  does the trick. I used 1.5. Anything higher and the contrast of Ha was too high for my data. It also helped limit the noise in the result.
- Greg
Scottsdale, Arizona, USA

Offline llpastro

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Re: (HA-R)GB
« Reply #2 on: 2017 November 24 06:21:59 »
Would share where to find these scripts?  Thanks.

Larry
AP 140 Refractor
SBIG ST-10XME
AP Mach 1 Mount
ATS Portable Pier
Tucson, Arizona

Offline Greg Schwimer

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Re: (HA-R)GB
« Reply #3 on: 2017 November 24 10:32:59 »
- Greg
Scottsdale, Arizona, USA

Offline llpastro

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Re: (HA-R)GB
« Reply #4 on: 2017 November 25 06:48:11 »
Thanks Greg.  Is Kayron's essentially the same as Vicent's?

Larry
AP 140 Refractor
SBIG ST-10XME
AP Mach 1 Mount
ATS Portable Pier
Tucson, Arizona

Offline Greg Schwimer

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Re: (HA-R)GB
« Reply #5 on: 2017 November 25 14:51:03 »
I think it is or at least a minor variation but I'll defer to Vicent's input. My notes from the PI workshop look very similar to what Kayron has there.

- Greg
Scottsdale, Arizona, USA

Offline pfile

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Re: (HA-R)GB
« Reply #6 on: 2017 November 25 14:57:18 »
we've discussed 'vicent's method' here many times and unfortunately vicent has disavowed the idea that there is a single 'vicent's method'. i think we established that the tutorial posted on the pixinsight website by vicent is not implemented by any script, but a variant that he had given at some time in the past is described on Harry's website and IMHO is implemented more generally in the NBRGBCombination script (which IIRC was originated by a long-dormant expert user called Silvercup and then expanded by another user. the threads are still here...)

rob