The share of the view's height a body's diameter fills when a fly-to
arrives in 'body' framing (see computeFocusForBody). Arrival used to
always frame the body plus its whole moon system, so a planet landed as
a small dot and its real surface texture was barely visible — reported
as wanting to "actually see the planet on arrival". 0.4 is big enough
to read the surface, small enough to keep the limb, some space around
it, and (see lookBiasClearanceDeg) a parent beside it all in frame.
The share of the view's height a body's diameter fills when a fly-to arrives in
'body'framing (see computeFocusForBody). Arrival used to always frame the body plus its whole moon system, so a planet landed as a small dot and its real surface texture was barely visible — reported as wanting to "actually see the planet on arrival". 0.4 is big enough to read the surface, small enough to keep the limb, some space around it, and (see lookBiasClearanceDeg) a parent beside it all in frame.