  The High-Energy Lightcurve Generator (HILIGT) is a new web-based tool which
allows the user to generate long-term lightcurves of X-ray sources. It provides
historical data and calculates upper limits from image data in real-time.
HILIGT utilizes data from twelve satellites, both modern missions such as
XMM-Newton and Swift, and earlier facilities such as ROSAT, EXOSAT, Einstein or
Ariel V. Together, this enables the user to query 50 years of X-ray data and,
for instance, study outburst behavior of transient sources. In this paper we
focus on the individual back-end servers for each satellite, detailing the
software layout, database design, catalog calls, and image footprints. We
compile all relevant calibration information of these missions and provide an
in-depth summary of the details of X-ray astronomical instrumentation and data.
