mass of lensing object        distance              Einstein ring radius
                         (parsecs)  (m)           degrees      arcseconds
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lensed by a star
   1 solar mass             100     3 x 1018     0.0000025      0.0089
 (2 x 1030 kg)            1,000     3 x 1019     0.00000078     0.0028
                         10,000     3 x 1020     0.00000025     0.00089

lensed by a galaxy
  1012 solar            100 Mpc     3 x 1024     0.0025         8.9
 (2 x 1042 kg)        1,000 Mpc     3 x 1025     0.00078        2.9
                     10,000 Mpc     3 x 1026     0.00025        0.89

lensed by galaxy cluster
  1015 solar          1,000 Mpc    3 x 1025      0.025         89
 (2 x 1045 kg)       10,000 Mpc    3 x 1026      0.0078        28
                    100,000 Mpc    3 x 1027      0.0025         8.9
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