| Abstract: We present a systematic eclipse and scintillation analysis of two spider millisecond pulsars, PSR J1810+1744 and PSR J2051−0827, using full-orbit, multi-frequency uGMRT observations. Direct transverse-velocity estimates from pulsar timing can be difficult for spider MSPs because excess timing noise often contaminates residuals; scintillation provides a complementary and practical route to constraining transverse motion. We measure the diffractive scintillation bandwidth and timescale using two-dimensional autocorrelation functions of the dynamic spectra, and infer scintillation velocities under a thin-screen approximation. For PSR J1810+1744, we report the first scintillation-velocity measurement, obtaining a characteristic speed of ∼94 km s⁻¹, while for PSR J2051−0827 we derive a higher scintillation speed of ∼170 km s⁻¹. From the decorrelation bandwidth we also estimate scattering timescales and find a frequency scaling shallower than the canonical Kolmogorov expectation. Eclipse diagnostics reveal contrasting behavior: PSR J1810+1744 shows complete eclipses up to ≈1.5 GHz, implying a comparatively large electron column density within the eclipse region, whereas PSR J2051−0827 remains detectable in band 5, placing its eclipse cut-off frequency below 1 GHz. Finally, we quantify the eclipse-width evolution with frequency for PSR J1810+1744 and discuss implications for the dominant eclipse mechanisms in spider MSPs. |
