Difference between NIMA and JPL ephemerides for (50 000) Quaoar in right ascension weighted by cosδ (top) and declination (bottom) during 2011–2016, by using only the positions until October 2012 (left) and by using the positions until October 2012, and the two positions from the two previous occultations in May 2011 and February 2012 (right). The grey area represents the uncertainty of NIMA ephemeris and the blue bullets and their error bars represent the positions from the offset observations used for NIMA ephemeris.