ZTF image data is a large-scale time-domain survey dataset acquired by the 48-inch Samuel Oschin Schmidt Telescope located at Palomar Observatory in the United States. The facility is equipped with a 576-megapixel camera covering a 47 square degree field of view, scanning the entire northern celestial sphere every 2-3 days with a limiting magnitude of approximately g~20.8 and r~20.6 (AB magnitude, 5σ, 30-second exposure).
ZTF data products include single-epoch images (exceeding 69 million to date), coadded reference images (approximately 188,000), difference images, PSF-fit photometric catalogs, and real-time alert streams, all publicly released through the NASA/IPAC Infrared Science Archive (IRSA). These data are extensively utilized for the discovery and study of transients including supernovae, variable stars, active galactic nuclei (AGN), gravitational wave electromagnetic counterparts, and near-Earth asteroids, representing one of the most important time-domain survey data resources prior to the Rubin Observatory (LSST) era.
This dataset contains image data for Field 792, a special deep-field tile that overlaps with the Hubble Space Telescope's EGS (Extended Groth Strip) deep field. The EGS field is a renowned deep-sky region observed by Hubble's ACS (Advanced Camera for Surveys), centered at right ascension 214.825°, declination +52.823°, covering a rectangular area of approximately 10.1 arcminutes × 70.5 arcminutes. Field 792 has multiple CCD quadrant overlaps with the EGS field, particularly rcid 5 (readout channel 5) and rcid 23 (readout channel 23). The overlapping region between Field 792 rcid 5 and the EGS field spans approximately 10.2 arcminutes × 37.5 arcminutes. This field has accumulated 1,218 exposures in the g-band, 1,279 exposures in the r-band, and 445 exposures in the i-band from March 2018 to December 2024. The right ascension range is approximately 214°-215° (about 14h20m-14h28m), with declination around +52° to +53°.
Due to its overlap with the Hubble deep field, Field 792 has become an important region for studying active galactic nucleus (AGN) variability, tidal disruption events (TDEs), and other phenomena, combining the advantages of ZTF's high-cadence time sampling with Hubble's high spatial resolution.