Vela SNR in RGB and NB

[avandonk]

Here is panel one of a large mosaic. 7MB


http://d1355990.i49.quadrahosting.co..._P1_RGB+NB.jpg


Bert

[Spookyer (Brett)]

I find this a very interesting object but a bit beyond me at this time. Looking forward to seeing the whole thing in such great detail.

[avandonk]

Brett here is a mosaic I did some years ago with a Canon5D and 300mm F2.8L lens.

The FoV is about 11x11 degrees. 18MB

http://d1355990.i49.quadrahosting.co...VELASNRMOS.jpg


My major problem was colour gradients.


Bert

[Stevec35 (Steve)]

Another fantastically detailed image Bert! I should know this but what equipment do you use?

Cheers

Steve

[avandonk]

Here is a full res RGB image 5MB

http://d1355990.i49.quadrahosting.co...SNR_P1_RGB.jpg

It is obvious how dim the Vela SNR really is.


Here is the narrow band image 5MB


http://d1355990.i49.quadrahosting.co...VSNR_P1_NB.jpg


This is a screen capture of EasyHDR where I used these two images to blend the RGB and NB. 3MB


http://d1355990.i49.quadrahosting.co...2/screenP1.jpg


The advantage with this method is that you can set the EV difference to change the mix of RGB and NB. It allows full control of saturation, contrast and curves while using all the data of both images. The algorithm that EasyHDR uses to match data in different length exposures is based on the human visual response. This produces a far more 'natural' HDR image.

The result is all the stars now have their RGB colours and the faint emission nebulae are enhanced by the NB data. The dim and dark dust is also rendered realistically.


Bert

[avandonk]

Originally Posted by Stevec35

Another fantastically detailed image Bert! I should know this but what equipment do you use?

Cheers

Steve

Astrograph is an Officina Stellare RH200 which has a focal length of 600mm and is F3. Clear aperture is 200mm.
FLI Atlas Focuser.
FLI ten position filter wheel CFW-3-10 with 50mm square filters.
Astrodon E series LRGB and HA, NII, SII and OIII 3nm NB filters. Also a continuum filter 5nm.
Camera is a FLI PL16803 which has a sensor size 36.8 X 36.8 mm.
The FoV of this system is 3.5 X 3.5 degrees.
Mount is a Software Bisque PMX.
All housed in a roll off roof observatory in my backyard in Eltham.



As you can see very good equipment. The real weak link is myself as I have a lot to learn still. But that is the real fun of any hobby.

Bert

[Ross G]

A beautiful detailed photo Bert.

Ross.

[gregbradley]

Nice work Bert. One thing I think you might find helpful is the free HLVG plug in for Photoshop. It removes excess green and green noise (often a problem in deep sky images).

It will make balancing colour much easier. Some of the stars on my monitor have a slight green bias. It will bring out the better and stronger blues.

Greg.

ps. I looked at your image again and realised you have all that lovely teal green O111 filament colour in there. So the HLVG would not work on this image unless you were able to select the stars only otherwise it will wreck those lovely green hues.

[avandonk]

Originally Posted by gregbradley

Nice work Bert. One thing I think you might find helpful is the free HLVG plug in for Photoshop. It removes excess green and green noise (often a problem in deep sky images).

It will make balancing colour much easier. Some of the stars on my monitor have a slight green bias. It will bring out the better and stronger blues.

Greg.

ps. I looked at your image again and realised you have all that lovely teal green O111 filament colour in there. So the HLVG would not work on this image unless you were able to select the stars only otherwise it will wreck those lovely green hues.

You are quite correct Greg. If I use HLVG on the final RGB+NB it turns the teal OIII regions to blue.

I used it only on the RGB data before merging with the NB data with EasyHDR. As all the green noise originated from left over bits of green gradients in the RGB data, it worked a treat.

Here is the result 6MB

http://d1355990.i49.quadrahosting.co...GB+NB_HLVG.jpg

Here is an animated gif of the improvement with HLVG. 500k

http://d1355990.i49.quadrahosting.co...4_01/HLVGs.gif


Thanks for the tip. With Pixinsight's DBE able to get rid of even bad gradients. This green noise was my next problem.

I tried HLVG on a few RGB images and it does a fine job of eliminating green noise.

Thanks again. Bert