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Spectroscopic applications

Calculating precise spectroscopic radial velocity measures or redshifts. More...

## Classes

class | supernovas::Apparent
| Apparent position on sky as seen by an observer at a specific time of observation. More...
class | supernovas::CatalogEntry
| Defines the astrometric parameters of a sidereal source, such as a star, a Galactic cloud, a distant galaxy, or a quasar. More...
class | supernovas::ScalarVelocity
| A scalar velocity (if signed) or speed (if unsigned). More...

## Detailed Description

Calculating precise spectroscopic radial velocity measures or redshifts.

When defining catalog (that is non-Solar-system) sources SuperNOVAS allows you to specify spectroscopic velocity measures, either as a Solar-system Barycentric radial velocity, or relative to the Local Standard of Rest (LSR), or as a redshift measure (z). And, when you calculate apparent places in an observing frame, SuperNOVAS will use that information (or the geometric velocity vector obtained for Solar-system bodies), to calculate the precise spectroscopic radial velocity that the observer would measure, using the appropriate relativistic formulae to account for both the kinetic and gravitational effects, including projection effects due to gravitational bending.

The spectroscopic measure of velocity (vr) or redshift (z) is one that relates the wavelength of the observed light (λobs) to that of the emitted light (λrest):

λobs / λrest = 1 + z = [(1 + vr / c) / (1 - vr / c)]1/2,

where c is the speed of light.