An Interesting execise.

[Hagar (Doug)]

This image of IC2944 (Running chicken is a compilation of data.
The RGB data was collected last night with a QHY9 with Baader LRGB filters. 3X 10 minute exposures of each RGB and 4 X 10 min Luminance.

I have blended this with some Ha datya I collected a few weeks ago with Atik 11002M mono camera and a Baader 7nm Ha filter.

The blend is HaL HaR G B and was quite a bit more complicated than I had thought. The differing size images had to be sized and aligned using Registar then taken into CCDStack and realigned manually to take care of the rotation between both sets of images.

The RGB data was stacked and the initial colour image created in CCD Stack. The Lum Ha blend and R Ha blend were createdor combined in Photoshop then combined with the original RGB image.

The whole process to quite a few hours and looking at the high Res version I think I could probably do a slightly better job of aligning the Ha with the other data.

This is it so far with Hi res image HERE

[allan gould]

Nice image, Doug. Register is really worth the money when it comes to aligning two disparate image sets to each other.
Was worth the effort but I never can see a chicken in it!

[gregbradley]

What software do you use to align your masters? I use CCDstack as it has an awesome addin that is super accurate.

You can align in PS but if there is rotation involved it can get a bit tricky. Put the Ha in new layer above your RGB. Then reduce the opacity to 50%. Now you can see both layers. Click on the move tool. Now move using the arrow keys on the keyboard to align Click the layer on and off with opacity back at 100% to see if they align perfectly and move until they do.

If it needs to be rotated then Control T sets it to transform mode. Now the cursor when at the corners (downside is the image has to be small enough to put the cursor outside it - at least PS CS2 is like that) turns into a curved arrow and you can spin it or you can stretch it anyway you like. Once aligned hit "enter" to finalise the transform mode.

CCDStack though is 10 seconds work.

Here's the problem with Ha + L. Some of your stars are too red.
Ha + L needs to be set at a balance and not 100% each. It may be 35% Ha. But you could do an inverted mask and block the Ha out of the stars that way if you did Ha as a separate layer.

Even better use Ha as a separate layer, set it to red (by deleting green and blue channels) set it to lighten - now curves pushes it up only.
Use an inverted mask so it does not affect the stars. You could pull the stars out of the image whilst still rgb and add them in later once the Ha has been done.

Ha is a processing beast and needs to be whipped into line in my opinion. It takes over very easily, can wreck star colours, can cause the salmon colour or become too red. I reckon you whip it down and keep it in check and protect your stars.

One approach I have found that can be good is to set Ha to a separate layer, set to lighten. Duplicate the layer 3 times (its already aligned earlier in CCDstack). Now on the first layer you erase the blue and green channel. So now you have a red Ha layer and can adjust it using curves. It won't lower the colours only add using curves.

I then erase the red and green channels of the 2nd layer to give me blue. Usually I set the opacity down to about 10% as you only want a touch of this. The third layer often looks good set to luminosity. Adjust the opacity to suit. Too much and you bleach out the colours. A bit adds vibrance and detail.

If you want more red you can simply duplicate the Ha as red layer. Or you can put another duplicate layer above it set to saturate and adjust. Setting the first layer to screen creates a much heavier red effect but it may be too much but good to know in case that is what you need. Especially if the Ha is only subtle and you want to boost it.

I find it best to mask the effect of each of these. Use Louie's inverted mask tutorial about how to do that. Its pretty easy once you've done it a few times. I can walk you through that if you are interested. Send me a pm and I can list the steps. The inverted mask is good because it protects your stars which Ha often attacks.

Greg

[multiweb (Marc)]

Originally Posted by gregbradley

I use CCDstack as it has an awesome addin that is super accurate.

CCDIS is great with star patterns as long as the subs are similar in orientation and have similar image scale. I doesn't work with overlapping and mosaicing. When it comes to accurate alignment of various files with different image scales registar is the standard. It wins hands down. btw very nice pic Doug.

[Hagar (Doug)]

Thanks Greg I will have a look at Louie's tutorial. and I will give your method a trial as well. I normally use CCDStack for all my alignment but when the images to be aligned are from two totally different frame sized cameras Rgistar falls into a class of it's own. I always run the registar created and sized images through CCDStack as well and in some cases this requires some rotation which must be done in manual mode to get just right. This could do with another run through and a bit of a tweak to the rotation of the Ha to align correctly for the alignment with the RGB data.
I will get around to it shortly. I hope.

[gregbradley]

Oh I must've missed that. So the Ha is from 2 different cameras. Yeah Registar is the king there. But if you used an already aligned master from your LRGB as the base image in Registar wouldn't that get it perfect?

That way you are always aligning back to your LRGB image.

Greg.

[Hagar (Doug)]

Originally Posted by gregbradley

Oh I must've missed that. So the Ha is from 2 different cameras. Yeah Registar is the king there. But if you used an already aligned master from your LRGB as the base image in Registar wouldn't that get it perfect?

That way you are always aligning back to your LRGB image.

Greg.

Hi Greg, You would think the aligment would be perfect but as a general rule I have found that the image does show some rotation which cannot be handled by Registar during the scaling process and I think any rotation changes are based on the centre of image rather than the guide star used which in most cases is a diferent star (at least for me). Maybe I should record info on images , guide stars for use over several nights but I do find it easy enough to adjust the rotation in CCDStack after correcting image scale in Registar. May be not the correct method but it does work for me.