## Overview

We add radial velocities to the fit and include the stellar masses as
fit parameters.
## Steps

Bring up the Data|Spectroscopy widget and load the file *zetuma.vel*.
Type `calcmodel` to compute the model for the astrometric and
spectroscopic data.

Select the fit parameters as shown on the left. Then click "Fit".
(If you do not wish the fit algorithm to edit eigenvalues inside
the singular-value decomposition method, you can use the Fit|Control
widget to lower the tolrance level to 10e-9.)

Use Plot|Astrometry and Plot|Spectroscopy to plot the fit results.

You can now look at the numerical results by clicking the component labels in the model
fit widget.