Limitations to Telescope Performance, Small Versus Large Telescopes, the Rationale for Mt. Top Observatories
OPD < 1/14 wave RMS, if Dt < ~ 5Da
- Star image “perfect” for sharpness
- Star image is in motion
- Only possible for small telescopes
- Or large telescopes perhaps, in “…quiet Air, as may perhaps be found on the tops of the highest Mountains above the grosser Clouds.”