aligning and stacking astronomy pictures

[sandroi]

Hi

I am experiencing problems for aligning layers. These are astronomy pictures which have mainly dark backgrounds and a few luminous features, let's say a planet and which is quite small with respect to the dark background.

When attempting layer alignment either with AUTO or REPOSITIONING options, the message I am receiving is  that alignment is not possible since the frames should overlap for at least 40%. Any suggestion to get around with that? Could an alignment be performed manually?

[davescm · Accepted solution]

You may need to do it manually. To do that:

Turn on visibility of two layers and reduce the opacity of the upper layer to say 50%.

Now move and transform the upper layer into position to get your alignment

Turn up the opacity of the upper layer to 100%

Check for accurate alignment by switching the upper layer to Difference blending mode. The aligned overlap should go black (i.e. no difference)

Turn blending mode back to normal and turn visibility off.

Turn on visibility of the next layer and turn down opacity to 50%...........

Repeat as needed until all layers align - always aligning to the same base layer so you do not build up a cumulative error.

You can then go on to make smart object and use the stacking mode you need with the aligned layers if they are of the same subject over-layed, or go on to add masks if the images are side by side with overlaps.

Dave

[sandroi]

Thank you Dave. I am working following your suggestion and it seems that I am getting there. Thanks again

sandro