Compositing difficult picture

[Astrogeezer]

output-stack-DeNoiseAI-standard-affinity-extended.tiffoutput-stack-DeNoiseAI-standard-affinity-extended.tiffHi, I'm trying to create a composite Milky Way landscape photo.  I've done it before with other landscapes.  I can't seem to do it with this landscape because of the trees.  I'm unable to cleanly separate the landscape from the sky so I can then replace the sky with the Milky Way.  Please let me know how I can make successfully combine these two photos.

 

 

 

[Lee D]

@Astrogeezer I think it's a case of making a general selection and then spending time with the Refine feature to tidy the selection up around the trees/bushes. Then outputting to a new layer with mask so you have the option of still working on the mask.

Hopefully the images are of high res to help with the selection.

[User_783649]

Another and possibly more simple way of doing this is visually analyzing both images before making any adjustments. 

Let's look at your first image. The sky area is clearly the brightest part of the image and is clearly separated from the rest. The second image is overall dark and horizon line is clearly visible.

We may try to utilize Multiply blending mode here so light area of the first image will be merged with dark area of the second image in the same spot. And by adding a simple gradient fill to the mask we may tell where we want it all to stop.

After all we may get something like this (and hey, we haven't even touched those selections yet):

[Lisbon]

One option is to mask based on a channel.
I used the green channel (inverted).

To prevent the channel mixer from affecting unwanted areas I had to paint the mask with black.

[Astrogeezer]

Thanks everyone for chiming in.  I'm still a newbie, floundering around pretty badly.  However, I hope to learn some tricks to create the kind of photos I want to see.

Alex, I'm going to try your path first as it looks the easiest.  I wonder if you can provide more detailed instructions when using the gradient.  When I tried it, the starfield turned black and white.  Thanks in advance for all of your help!

[Granddaddy]

If you are looking for tutorials on selections, I have pointed to some excellent sources in my posts at

https://forum.affinity.serif.com/index.php?/topic/143743-remove-background/#comment-798313

https://forum.affinity.serif.com/index.php?/topic/143743-remove-background/&do=findComment&comment=798819

Tutorials on using layers effectively are pointed to in my post at

https://forum.affinity.serif.com/index.php?/topic/120711-good-basic-tutorial-on-layers/&do=findComment&comment=658279

 

[Astrogeezer]

Thanks, Granddaddy!  I'll check these links out.