NASA ultraviolet/X-ray mission, also known as OAO-3
Copernicus, or Orbiting Astronomical Observatory 3 (OAO-3) was a collaborative effort between the USA (NASA) and the UK (SERC). The main experiment on board was the Princeton University UV telescope, but it also carried an X-ray astronomy experiment developed by the University College London/Mullard Space Science Laboratory.
Lifetime : 21 August 1972 - February 1981
Energy Range : 0.5 - 10 keV (X-ray experiment only)
The University College London X-ray Experiment (UCLXE) consisted of 4 co-aligned X-ray detectors
- 3 Wolter type 0 grazing incidence telescopes with 2 proportional counters (3-9 Å and 6-18 Å) and a channel photomultiplier at the foci. (variable FOV from 1 to 12 arcmin)
- 1 proportional counter (1-3 Å) with a simple collimation tube. (2.5° X 3.5° FOV)
- Discovery of several log period pulsars (e.g. X Per).
- Discovery of absorpton dips in Cyg X-1.
- Long-term monitoring of pulsars and other bright X-ray binaries.
- Observed rapid intensity variability from Cen A.
Source: wikipedia, NASA