In practice ak(t), where t is the morphological type,
is tabulated as follows: ak(-5)=0.15 ak(-4)=0.15 ak(-3)=0.15 ak(-2)=0.15 ak(-1)=0.15 ak(0)=0.15 ak(1)=0.125 ak(2)=0.100 ak(3)=0.075 ak(4)=0.065 ak(5)=0.055 ak(6)=0.045 ak(7)=0.035 ak(8)=0.025 ak(9)=0.015 ak(10)=0.005
When unknown, v is assumed to be 0, i.e. no k-correction is applied, and when
t is not known, a value of 2
(mean morphological type in the database; spiral galaxy) is assumed.
ai is taken as 0 when unknown. btc is not computed when v > 30000 km/s or bt or ag
is unknown.