Acer Palm pruning question

I have a Jap. maple purchased at a nursery.  It was repotted into an Anderson flat mid-May; placed in partial shade to settle into new pot.  Basic pruning was also done to thin canopy leaves to allow light below.

The tree needs pruning of primary branches to compact it and provide shape.  All references point to autumn for shaping/pruning.  Should I wait or can I prune branches in summer? (pic from early spring before repot) 

You do not mention how long you have had the tree. But I guess purshased this spring and you have already rushed into repotting. Am I right?

The right time for pruning you already know. While it may be possible to hard prune in summer, it is more risky. Especially if you have repotted in may. The poor thing has not established in the new pot yet.

in my opinion, next window for hard pruning is authum 2026. But only if the tree grow well in summer 2026.

Why the urgency? Why take the risk? I do not get it. Bonsai is a maraton, not a sprint. Love your tree for what it is and what it can become.

Tropfrog, thanks for the info.  Being new to bonsai, it's hard to judge some of these timing questions. 

"in my opinion, next window for hard pruning is authum 2026. But only if the tree grow well in summer 2026."  very helpful, thanks

"But I guess purchased this spring and you have already rushed into repotting. Am I right?"  Yes, I purchased it this spring.  The nursery had it in that pot for at least a couple of years.  Should I have waited to repot it?  I'm not looking to thicken this tree or add size and the tree is very healthy.  Why would I want to keep it in the nursery container?  I'm keen to learn and would like to hear your (and others) approach.

Thanks again,
Mark

Generally beginners hurry far to much.

I always wait at least one year after purshasing a tree before doing any work and I always wait at least a full growing season between big works. But it is a minimum, not a maximum. I still have trees from my first year in the hobby not yet repotted. That is 8 year now.

That's a very nice Maple you have, a lot of potential, nice trunk and base...
I would tell you to look for help before you decide how to prune it or style it, you can take a wrong decision by not having experience, and ruin a good material by lack of simple knowledge...
Take this time to study the species, learn how to keep it alive and healthy, that's an important part of the hobby...