Sinus Iridum
What Sinus Iridum is
Sinus Iridum is a sinus — a bay-shaped dark plain — on The Moon, 249 km across, centred at 45.0° N, 31.7° W in the Sinus Iridum quadrangle. It is the 66th largest named feature on The Moon and the 3rd largest of its class there.
Where the name comes from
"Bay of Rainbows." The International Astronomical Union approved the name in 1935, under the theme it applies to every sinus on The Moon.
What it would take to settle Sinus Iridum
The Moon scores 29.1 as a world. That number is the same for every square metre of it — but sunlight, water, radiation and the ground under your feet are not. This is the same question asked at 45.0° N, 31.7° W.
What this spot has going for it is earth link — near side — Earth stands 37° above the horizon and never moves. What works against it is water — outside the ice-bearing latitudes.
Computed from Sinus Iridum's catalogued latitude, longitude and feature class — 84% of the model's weight had a basis here, and one axis was dropped as not applicable to The Moon (radiation geometry). Gravity, pressure, delta-v and distance from the Sun are the same everywhere on The Moon and are already counted in the world's own index, not again here.
What this cannot see: elevation. Slope, local shadowing and the polar “peaks of eternal light” — ridge tops near the poles of a barely tilted world that catch sun almost continuously while a crater floor kilometres away never does — need a terrain model this does not have. Where a real mission targets a pole, that is usually why.
What is next to it
The largest sinus features on The Moon
All 12 sinus on The Moon — mapped together, with the naming theme and the size distribution.