This paper presents a comprehensive study of the eclipse properties of the spider millisecond pulsar (MSP) J1908+2105, using wide-band observations from the uGMRT and Parkes UWL. For the first time, Ghosh et al. observed that this pulsar exhibits extended eclipses up to 4 GHz, the highest frequency band of the Parkes Ultra-Wideband, making it one of only three MSPs known to have such high-frequency eclipses. This study reveals synchrotron absorption as the primary eclipse mechanism for J1908+2105. They present modeling of synchrotron optical depth with various possible combinations of the parameters to explain the observed eclipsing in this as well as other spider MSPs. Observed eclipses at unusually high frequencies for J1908+2105 significantly aided in constraining the magnetic field and electron column density in the eclipse medium while modeling the synchrotron optical depth. Combining their findings with data from other MSPs in the literature, for the first time authors note that a higher cutoff frequency of eclipsing, particularly above 1 GHz, is consistently associated with a higher electron column density (>10¹⁷ cm^‑2) in the eclipse medium. Additionally, they present the first evidence of lensing effects near eclipse boundaries in this MSP, leading to significant magnification of radio emissions. The orbital-phase-resolved polarization analysis presented in this paper further indicates variation in rotation measure and consequently stronger magnetic fields in the eclipse region.

The image above shows electron density variation near eclipse boundary in different epochs observed with uGMRT at 400 MHz; 650 MHz and with Parkes UWL at 2368 MHz. A sharp dip around orbital phase ~ 1.42 on 14 June 2024 suggests a localized gap in the ionized gas, likely caused by turbulence in the plume. The absence of this dip in data from 11 days earlier indicates variability in timescales of days to weeks.