represent planets as symbols

[axd1967]

Is your feature request related to a problem? Please describe. I'm interested in getting more fluent in recognising the astronomical symbols of planets.

Describe the solution you'd like

An option to replace Earth, Moon and planets by their astronomical symbol, in constant size irrespective of distance or brightness (in the current projection mode from the current observer position).

This would additionally be very interesting in solar system observer position to create diagrams similar to Heavens Above.

Compare

to

Describe alternatives you've considered

Additional context See also symbols referred to in #1627

[github-actions[bot]]

Thanks to @axd1967 for suggesting this feature.

[alex-w]

Added for didactic purposes into AstroCalc/Positions tool