Figure 2.19: The parallax accuracies in the final solution, as a function of magnitude,
for 26 268 stars with parallaxes errors below 10 per cent. The bi-modal structure is
a reflection of the scanning strategy, with stars near the ecliptic poles having much
better coverage, and thus higher parallax accuracies, than stars near the ecliptic
plane. The separation between the two groups is at ecliptic latitude of 47◦ .