PixInsight Forum (historical)

PixInsight => General => Off-topic => Topic started by: kwiechen on 2011 July 13 00:06:36

Title: combination of H alpha with R/L using the maximum operator
Post by: kwiechen on 2011 July 13 00:06:36

Hello,

can anyone show me the pixelmath equation to combine H alpha for example with R using the maximum operator? Is it useful to apply a Linearfit before?

Or is there already an implementation of the new approach for the combination http://pixinsight.com/forum/index.php?action=post;board=5.0

Thank you very much!

Best

Kai

Title: Re: combination of H alpha with R/L using the maximum operator
Post by: kwiechen on 2011 August 28 04:48:54

Hello,

I have tried to combine H alpha data with (rather poor and noisy) broadband data using the technique described here http://pixinsight.com/tutorials/narrowband/theory/en.html. The resulting continuum map looks very strange and so I have stopped this.

Then I have tried http://pixinsight.com/forum/index.php?topic=1754.msg10429#msg10429 to combine Ha/R and Ha/L using the max operator from pixelmath. As I am using the Astronomik LRGB filter set, I think it may be appropriate to blend some H alpha data in B and G to simulate H beta too.

I have tried

max( (blend_factor * Ha + (1 - blend_factor * Broadband), Broadband )

to control transfer of H alpha into broadband data without affecting star size after aligning the background using the AutoHistogram tool (blend_factor 0.8 for R, L, 0.1 for B, 0.05 for G for example).

http://img51.imageshack.us/img51/4371/ic1848halharhaghab.jpg

Best

Kai