<Dl> <Dd> M B ≈ M V ≈ − 19.3 ± 0.3 . (\ displaystyle \ M_ (B) \ approx M_ (V) \ approx - 19.3 \ pm 0.3 \, .) </Dd> </Dl> <Dd> M B ≈ M V ≈ − 19.3 ± 0.3 . (\ displaystyle \ M_ (B) \ approx M_ (V) \ approx - 19.3 \ pm 0.3 \, .) </Dd> <P> Therefore, when observing a Type Ia supernova, if it is possible to determine what its peak magnitude was, then its distance can be calculated . It is not intrinsically necessary to capture the supernova directly at its peak magnitude; using the multicolor light curve shape method (MLCS), the shape of the light curve (taken at any reasonable time after the initial explosion) is compared to a family of parameterized curves that will determine the absolute magnitude at the maximum brightness . This method also takes into effect interstellar extinction / dimming from dust and gas . </P> <P> Similarly, the stretch method fits the particular supernovae magnitude light curves to a template light curve . This template, as opposed to being several light curves at different wavelengths (MLCS) is just a single light curve that has been stretched (or compressed) in time . By using this Stretch Factor, the peak magnitude can be determined . </P>

To calculate the dashed orbits from the stellar positions astronomers had to assume that _