Venus

Sketch the outline on separated evenings or mornings. A thinner crescent generally accompanies a larger apparent disc, so brightness alone gives a poor idea of what the eyepiece will show.

Venus can be conspicuous in twilight when well placed, but its phase is not a routine unaided sight. Confirm its position in the calculated sky rather than searching close to the Sun.

Ordinary handheld binoculars mostly show glare. A large crescent can become distinguishable with sufficiently magnifying, firmly supported binoculars, but a telescope makes the test easier. Keep the Sun safely below the horizon during any optical search.

Try 40–100× in a small telescope and concentrate on the illuminated edge. Use the lower end for a large crescent and adjust for a smaller disc. Medium and large apertures do not uncover the surface: subtle cloud shadings are difficult specialist observations. Focus carefully before interpreting a coloured or doubled edge as real structure.

Observe after sunset or before sunrise, with the Sun below the horizon throughout. Twilight offers useful contrast before Venus sinks too low; a fully dark sky is unnecessary. Heat shimmer and atmospheric dispersion can spoil the outline even on a cloudless evening.

Start without a filter. If glare is uncomfortable, a mild neutral-density or polarising filter is a comfort experiment, not a way through the clouds. Such filters provide no protection from the Sun.

Venus orbits inside Earth's orbit, giving us different views of its sunlit hemisphere. Dramatic ultraviolet cloud images should not set expectations for an ordinary visual view.