[patcheudor]

Most people don't mount their cell phones to tripods or celestial tracking mounts so there's enough movement it would never be an issue. It would be interesting to mount one to a celestial tracking mount and see what happens. Honestly, I've got some old cell phones laying around here and might just give that a try.

[penagwin]

That would be really cool to see! /u/tzs posted some links, so it looks like people a somewhat unsure. I'm guessing that if the sun is well tracked in the center for long enough that it would damage the lens. I guess we don't have a ton of hard data for it.

[owenversteeg]

So I've photographed lasers a bunch and burned a few sensors, I guess I should toss in my experience. As far as I can tell, it really depends on the specific phone that you're using, and also the damage is usually fairly minimal. I've damaged fancy sensors with lasers and they almost always have major problems afterwards, but for years I used a phone with a very severe amount of laser damage to the sensor and the photos were quite good and the damage was barely noticeable (as a series of black lines on the image.) There was no damage to the lens.

I also doubt it would be the lens damaged in the case of a smartphone. The lenses are built to take a tremendous amount of abuse and almost certainly would be fine. The sensors are by far the more fragile component.