All-sky distribution of pulsars used in this work in the equatorial coordinate system. Top: pulsars in Gaia DR3. Bottom: pulsars in the PSRπ and MSPSRπ projects. Different marks are used to distinguish pulsars whose timing solutions refer to different ephermerides, that is, blue open triangles for DE200, green open stars for DE405, purple open inverted triangles for DE421, yellow open squares for DE430, and red open circles for DE436. The dotted curves indicate the location of the ecliptic plane.