NGC 2070 with DBE and HLVG

[avandonk]

Light pollution causing gradients is a major problem with the sky at my observatory site i.e. home in the outer suburbs (16 km) from Melbourne.

PixInsight has a module called Dynamic Background Elimination or DBE which works very well to get rid of even bad gradients. My data still had remnants of these gradients especially in the green channel.

Greg Bradley put me on to HLVG here

http://www.deepskycolors.com/archivo/2010/04/26/hasta-La-Vista-Green.html

This is quite good minimising green noise in RGB data.

An example. NGC 2070 at 1.5 times native pixel size in RGB 20MB

http://d1355990.i49.quadrahosting.com.au/2014_01/NGC2070_RGB_HLVG.jpg


And again RGB plus NB 20MB

http://d1355990.i49.quadrahosting.com.au/2014_01/NGC2070_RGB_HLVG+NB.jpg


Bert

[niharika]

Hi Bert,
I haven't used HLVG yet. Does it work better than pixinsight's SCNR for green?
Regards
Raki

[LewisM]

I think it does. I have not tweaked the PixInsight one, but HLVG works a treat - and you can scale it customly with the fade function in PS.

[RickS]

HLVG is based on the SCNR algorithm: http://www.deepskycolors.com/archivo/2010/04/26/hasta-La-Vista-Green.html

[stevous67]

16km is really inner city Bert. Your gradients could be quite severe with that FOV, so DBE would be a image saver.

Steve

[avandonk]

I was being facetious about 'outer' suburb. It was, when I first moved here in 1959. Yes you are very correct that PixInsight's DBE is a data saver. It is like a very translucent coloured veil has been lifted. HLVG gets rid of the last bits.

I have been getting by with GradientXterminator but it attenuates real signal in the bright bits of a wide field image and increases real signal in the dim bits. The light pollution seems to get worse each year. I am even plagued with car drivers who have their headlights on high beam on my street. One twit used to park while he illuminated all the trees with his headlights on high beam and very bright driving lights for very long times at around midnight while he 'talked' to his girlfriend. His car was also idling very noisily. I went up at 2AM and explained the facts of life to him. He does his 'talking' in the dark with the engine off now, at least I think he does.

DBE has saved me from moving to a dark sky site, for now. I will buy PixInsight just for this module. I am sure with a lot of effort I may even be able to learn how to use more of its capabilities.

So much to do so little time left!

Bert