I get that they were taken at the same time, but really when you're blending two pictures to get this one, what's the difference between that and just photoshopping a picture of the ISS where it was at the exact moment.
Both images capturing different aspects. How much the artist does composing the images effects the realism, but what was done seems to be quite real.
For that reason, I would argue that these are 'true' photographs. Sure, things have been differently exposed, maybe some ultraviolet light has been brought into the visual spectrum; but for all intents and purposes, the light from the subject(s) hit the lens(es) at the same time and the composition is true to what actually happened.
Now, with all that being said, there are many famous photos that are actually composites [2] and what makes 'a true photograph' is still hotly debated.
Digital processing is such an integral part of modern photography that trying to decide what makes a 'true photograph' is bound to get messy.
[1] https://petapixel.com/2014/03/10/incredible-color-photograph... [2] https://www.youtube.com/watch?v=2NeyTEO_JP0
And it depends at least somewhat on the context. For photojournalism, compositing, highly misleading crops, removal/addition of objects, etc. is pretty much verboten. Whereas art/nature/etc. photography is much more flexible.
I knew someone who used to be really into photography contests at his camera club and he ended up getting discouraged and stopping doing it with the switch to scanning and then full digital because so many other people had "better" but highly manipulated photos.
Another question, if this had been done on film, would you feel differently? The process is the same (Well, more or less) to a double exposure. Does that not count?