Large scales, increased clipping planes, and performance

Questions & Answers
1

The standard clipping planes on the camera are 0.3 and 1000, near and far.
I’m experimenting with parallax vs real perspective movement in a space game.

In my 2D game 1 Unity unit/meter is 10 real world units, but I want to get nearby planets and backgrounds to move appropriately in the background as the player moves in X and Y.

One thing I’m trying is using a perspective camera and putting a sprite of a planet WAAY into the background and enlarging its scale. Scale = 50 and Z distance is 9000 currently. This is giving me a 10km diameter planet (.063% Earth-size approx) 90km away, according to my game’s own relative scale.
That size is workable for a game, but I wonder about having something bigger further in the background.

To do just this little I had to set the camera far clipping planes to 10,000 instead of 1,000. I’d like to go even x10 bigger than this again, so x100 times normal clipping distances, scales, and game distances.

Will those kind of numbers be doing terrible things to the performance I’m wondering, or is a couple of extra zeros no big deal to the engine?
Worth noting that there’s no physics or colliders on the enlarged planets.

2

If increasing far clip plane is not adding new objects in view than it is not changing performance. But in the other case if increasing far clip plane adds a new object in the scene it will affect the performance.
The camera uses Occlusion culling which allows the engine to discard anything far away from far clipping plane. It is an optimization technique used for very large maps.
In your case, I guess there is no change in the number of objects being drawn when you increase the far clip plane hence no change in performance.