H-alpha 7nm filter how to process

[johnb]

Hi

So filter is on order and will be used with my modded Cannon450d, what Im unsure about is how to process once I have the images, I assume without the filter that's the RGB element, so do I just put the combined RGB and the Ha image into DSS and register and stack or do I stack separately and then somehow combine in PhotoShop ?

Regards

John B

[ollypenrice]

You'll have to debayer the Ha somehow, and someone else will tell you how to do that because I've never done it. (Only a quarter of your pixels, the red filtered ones, will be picking up any red Ha light so the rest need to be stripped out.)

Don't ask DSS to combine your Ha because that's the artistic part!

There is lots on the web about the options but I use a simple routine. Once the Ha is aligned to the RGB I split the RGB in Channels in Ps and apply the Ha to the red in Blend Mode Lighten. While the Ha is pasted over the red in this blend mode you can play with the Ha in levels and Curves to judge its effect on the red channel. I apply it at full power and then, if the effect is too much, I paste the HaRGB onto the RGB and select the opacity which appeals.

Olly

[JacobvonChorus]

Extract the red pixels and discard the others. Combining the images is the fun part that can take a long time to do well in Photoshop. Trust me, always unique process and always fun.

Jacob