Cameras + Telescopes

[dryer_lint]

Cameras provide a way to actually have instruments that belong deeper in the tech tree. First were low res video, then for the moon, they actually took FILM images, and scanned them for facsimile transmission. Later cameras (Voyager, for example), used CCD cameras. I'd have early probes have low res video. Pods would all have high res photography (requires return to Kerbin to develop). Later probe cores can be assumed to carry CCD cameras... Or they could be separate parts if holding part count down isn't a huge goal (except the pod cameras, those are handheld devices).

As was said above S/N drives effective bit rates, but the bottom line is indeed bit rate, though it is not a part limited thing, but one of distance from the spacecraft to Kerbin.

Yeah, you would start out with the basic camera in the second tier, just in time to take photos in orbit. Then you would get the advanced one around the time you've "mastered" the Mun trip. Finally, the telescope would be a late-game part near the very end of the tree, achieved after your first interplanetary trip or something. (It would be late-game to prevent the "sit in Kerbin orbit and take pictures" thing you mentioned, and it would give reduced science anyways.)

Like I said in the OP, I think cameras have the potential to also give different antennas a use. Better antennas = better quality = better science, but antennas are expensive.

[tater]

If cameras (telescopes are just cameras with long lenses, though we can start talking about other instruments on them (or other wavelengths) were a thing (and to be worth doing at all, there would need to be something like scansat, and science would need to be actually done that way, not "science from orbit" points), I would have the following:

Film Camera (handheld). This camera is equipped in all manned parts. Film must be returned to Kerbin to be developed, so 0% transmission unless developed in the lab part, then 100% transmission. This is a good camera, and would would achieve different ground resolutions via altitude.

Low-res B&W TV camera. Default on ALL probe cores as a wide angle camera.

Film probe camera. High-res film camera with developer, and scanner. 100% transmission, limited number of shots (this might be abstracted by having it able to make X orbits of swaths in a scansat type setting). New part.

High-res probe camera. New part. Either TV or a later, CCD camera, both possible, no real need to clutter up the tech tree unless making it smaller is desired for later tech.

Perhaps probe cores could be given a storage capacity that would work like EC, with images filling storage based upon resolution, then they must be transmitted (perhaps making the antenna types meaningful would be done at the same time). This is important for planning missions as flybys or impacts vs orbiters that can take their time. In a perfect world of "fog of war," this might mean only imaging parts of various worlds.