unTimely: a Full-sky, Time-domain unWISE Catalog

We present the unTimely Catalog, a deep time-domain catalog of detections based on Wide-field Infrared Survey Explorer (WISE) and NEOWISE observations spanning 2010 through 2020 time period. Detections are extracted from 'time-resolved unWISE coadds', which stack together each biannual sky pass WISE imaging to create set ~16 all-sky maps (per band), much deeper cleaner than individual exposures. incorporates W1 (3.4 micron) W2 (4.6 channels, meaning that our data effectively consists ~32 full-sky catalogs. run crowdsource crowded-field point source photometry pipeline (Schlafly et al. 2018) epochal coadd independently, with low detection thresholds: S/N = 4.0 (2.5) in (W2). In total, we tabulate publicly release 23.5 billion (19.9 billion) at is ~1.3 mag WISE/NEOWISE Single Exposure Source Tables near ecliptic, further enhanced depth toward higher ecliptic latitudes. The Catalog primarily designed enable novel searches for faint, fast-moving objects, such as Y dwarfs and/or late-type (T/Y) subdwarfs Milky Way's thick disk or halo. will also facilitate other science applications, studies quasar variability mid-infrared wavelengths over decade-long baseline.