According to Dick Forsman, this has to be an adult Tawny Eagle because the head isn't pale enough, and the tail isn't bicoloured, which that should rule out Imperial Eagle.

The streaking (hackles) visible on the flanks, is not a sign of a transitional/immature plumage (as I thought), but is a trait of (some?) adults. Other fotographs show adult Tawny Eagles with an almost uniform dark brown plumage.

On the other hand, the obvious difference in lenght and degree of barring between the two (or more) generations of secondaries, may perhaps indicate that the bird is not in its final, adult plumage.
Is this bird the same as the much commented one?

It should be the same bird on all pictures, the plumage is the same and the pictures are taken exactly the same place 15 + 16/12.
A picture showing the primaries are now online.

Thanks Thomas!

I'm inclined to think that this bird indeed is an immature, contrary to what Dick Forsman concludes in his comment to your other photo of the same bird.

This is interesting since my initial suggestion that the prominent pale streaking of body-feathers was a sign of immaturity, was - admittedly - just a shot in the dark, based on my perception of adult Tawny Eagles as sporting a decidedly more uniform plumage.

Hope Dick will explain if the 'hackles' he mentions as typical for adults, are merely the lancet-shaped feathers on the nape, or if he's seen the extensive pale body streaking on true adult birds as well.