How far past the lens, along the line of sight — closer (small) = weaker lensing, farther (large) = stronger. 1500 = the traced default.
Background field
A scatter of extra sources, each its own distance
Enable field
Count24
Each new field member's own distance is picked randomly somewhere between the two values below — not a literal "nearest object" and "farthest object", a range to draw from:
Range: near end [Mpc]600
Range: far end [Mpc]4500
Overlays
Image plane — critical curves
Tangential (ring)
Radial
Source plane — caustics
Tangential
Radial
Markers
Source marker
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Source plane (β)
Image plane (θ)
Drag on the source plane · grid size adapts to lens cost (shown below)