After the rough cut (more of a what i have in hand and what i still need between) i saw that i needed 3 scenes. 2 are finished.
The last scene that i needed was an old full Lightwave scene i made nearly 1-2 years ago.
But i felt that i need a kinda closeup of the planet too in that scene.
The planet is fast to render in the beginning. But later it gets much slower.
I am still rendering and the scene is not finished.
So i used something i had not until now...2 things actually.
The first one is rendering only every second image and using PD Howler to morph the between frames.There are many cheap programs (like PD Howler) and expensive ones of course you can use for this.
I made a 10 frames test (the Terragen planet) with PD howler and made it to 280 frames.
Except just a small part it worked much better then i thought (it is a small moving scene).
It is very scene depended probably. A scene i tried 1 year ago wasn't so good for example.
And be careful PD Howler is still 32 bit and can crash with long-big scenes.
The second thing i tried with this scene was keyframing the image width and height . The beginning does have more planet ground but the finish is more cloudy.
So i made the image in the beginning Full HD and the finish Half HD.
It gradually lowers the height-width automatically.
The render times are constantly around 30 - 50 minutes per frame in this way.
It is great to have animation capability in nearly every option.
In principle it looks like it works...but not sure if the rendered result will work of course