Distributions of equatorial obliquity and cometocentric longitude of the Sun at perihelion for 51P/Harrington. Top left panel: histogram of equatorial obliquity, ɛ_{51P/Harrington}, with bins computed using the Freedman and Diaconis rule, while top right panel: uses the Bayesian Blocks technique. Similarly, the cometocentric longitude, ϕ_{51P/Harrington}, histograms displayed in the lower panels also use the Freedman and Diaconis rule (left) and Bayesian Blocks (right). Histograms are based on data from Table 4 (see the text for details).