Aligning RBG Channels in Photoshop

[roughy]

Hi all
The attached image was taken through LRGB filters about a year ago over several nights. Scope was centered manually each night because I didn't know how to plate solve until last week (pretty typical).

All images were registered, calibrated and stacked in DSS separately for each filter, opened in photoshop and pasted into the relevant channels in a new rgb layer.

Can anyone advise how, in photoshop, I can align each channel?
Cheers
Mark

[DavidLJ]

Based on an older version of Photoshop (v7) and using the Channels feature :

1 - Make visible (display the eye symbol) only the red and green channels.
2 - Select the green channel and the Move tool.
3 - Starting with the image fitted to the window zoom in a bit so that the centre of the image is enlarged.
4. - Use your mouse or keyboard arrow keys to move the green channel so that its stars lie over the corresponding red channel stars.
5. - While still zoomed in, scroll the image to display one corner and check to see if field rotation has moved the green channel stars away from the red channel stars. If so ...
6 - ... Select Edit | Transform | Rotate and use your mouse or the Delta adjustment box on the tool bar to rotate the green channel until its stars lie over the red channel stars - then deselect the rotation feature by double-clicking the image.
7 - Make visible only the red and blue channels and select the blue channel and the Move tool.
8 - Repeat steps 3 to 6 but this time using the blue channel instead of the green channel.
9 - Make all channels visible and save the result.

Hope this helps.

[Robert9]

Another way that might work for you is to:
1. Open all RGB images individually.
2. Select and copy green image. CTRL A, CTRL C
3. Select red image and paste green over the top. CTRL V
4. Do the same for the blue image.
You should now have a single image containing the tree layers.
5. From the menu-bar, select EDIT - Auto-align layers.

(I flying from memory but I think I have it right)

Hope that helps.

Robert

[roughy]

Many thanks Robert and David. Both methods appear to work fine.
Cheers
Mark

[Robert9]

That's great.
Robert