What technique involving optical aids helps observers see subtle stellar colors by gathering more photons?

Answer

Gently de-focusing the image slightly

By slightly de-focusing a telescope or binoculars, the star's light spreads out from a point source into a small disc. This increases the apparent size, gathering more photons to adequately stimulate the color-detecting cone cells in the eye.

What technique involving optical aids helps observers see subtle stellar colors by gathering more photons?
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