Carina New method

[avandonk]

Sorry but here it is 14MB

http://d1355990.i49.quadrahosting.com.au/2011_09/car_nm.jpg

Will explain all the new tricks when I understand them fully.

Bert

[avandonk]

Even a very high quality lens will have trouble focusing the visible spectrum and H alpha without having a slight halo. This results in purple (red+blue) haloes around white stars and a red halo around yellow/orange stars.

Because of the H Alpha at best focus the red and blue channels are not focussed as well as the green channel with one shot colour sensors.

I used to do a star reduction on the blue and red channels to minimise these haloes. I find it is far better to do it to all the exposure stacks before I tone map the HDR image.

Here is an animated gif showing 500% crops of the HDR images with and without star reduction to the blue and red channels of the different exposure stacks.

1.6MB

http://d1355990.i49.quadrahosting.com.au/2011_09/halo1.gif

Here is an animated gif of final HDR's. The old without any star reduction and the new method with star reduction to the blue and red channels of the different exposure stacks.

These images have the same colour balance!

2.7MB

http://d1355990.i49.quadrahosting.com.au/2011_09/finals01.gif


This is why the dust in the Corona Australis image is now a nice dust brown.

See here

http://www.iceinspace.com.au/forum/showthread.php?t=80837

Below are the two crops showing the halo reduction. The screen captures show the colour balance of the two images are the same.

Bert

[jjjnettie]

Thanks for the insight Bert.

[multiweb]

Cool write up. :thumbsup: Will have to try that.

[Ross G]

Great detail and colour Bert and an excellent explanation.

Thanks.

Ross.

[avandonk]

Here is the large mosaic of Carina to Centaurus done the same way

19MB

http://d1355990.i49.quadrahosting.com.au/2011_09/carmosS.jpg


Large version 37MB

http://d1355990.i49.quadrahosting.com.au/2011_09/carmosL.jpg

If you want to see full detail the larger version is better.

Bert

[jase]

Never stop learning Bert. Stunning image. I wait anxiously to see what you'll do with your new gear.

[richardo]

Wow:eyepop:, your last post with the mosaic is a jaw dropper Bert.
Sooo many stars, processed to perfection.
Just lovely!

Rich

[avandonk]

Thanks for the praise of the image Jase. You are quite correct that simply following any recipe limits the possibilities of any equipment. It has taken me some years to master? a DSLR and a lens for astrophotography. I think I have learned enough to take the next big step.
We used to discuss the concept of all solution space for the very big problems we used to handle at my previous work. Our biggest fear was to be stuck in a local minima far from the correct solution. Smug but wrong!

Why do I feel like I am going from a Holden station wagon to an F1 racing car with the new set up? I will proceed carefully and assume nothing.

The new system should keep me occupied until I turn back to stardust.

Bert

[avandonk]

Thanks Rich it has taken a lot of trial and error and practice.

Bert