3D-$N_{\rm H}$-tool

Absorption of light is one of the main selection effects limiting our ability to detect celestial sources, and ultimately, appearance of the sky across most of the electromagnetic spectrum. Recent advances in quantity and quality of available observational data and analysis methods led to major improvements in resolution, depth and fidelity of 3D dust distribution and extinction maps. The Galactic plane remains, however, essentially ``terra incognita'' beyond distances of a few kilo-parsecs due to the strong absorption in optical and near-infrared bands. Here I attempt to address this issue and present a 3D-$N_{\rm H}$-tool to estimate line of sight reddening and X-ray absorption column combining state of the art optical extinction and dust emission maps, and the results of dispersion measure modeling based on radio pulsar observations. The resulting maps are calibrated using independent absorption tracers and are accessible to general community via a convenient web-interface and full data cube.