Orbit of the white dwarf companion to R Aqr based on the orbital elements published by Hollis et al. (1997), with the longitude of the ascending node and periastron modified as discussed in § 4.6.4, computed for the epoch of the IOTA observations. The Mira star, H₂O shell, and the fitted model feature (at the two possible locations from Table 2) are also shown here. The SiO maser emission in R Aqr on 2006 September 16 is superimposed; color indicates velocity, red = −16.0 km s⁻¹, blue = −26.7 km s⁻¹.