Editing Compton Gamma Ray Observatory (section)

===EGRET===
{| class=wikitable style="text-align:center; font-size:11px; float:right; margin:2px"
|- style="font-size: smaller;"
| colspan=8 align=center|'''Instruments'''
|-
! Instrument || Observing
|-
| BATSE || 0.02 – 8 MeV
|-
| OSSE || 0.05 – 10 MeV
|-
| COMPTEL || 0.75 – 30 MeV
|-
| EGRET || 20 – 30 000 MeV
|-
|}
{{Main|Energetic Gamma Ray Experiment Telescope}}
The '''Energetic Gamma Ray Experiment Telescope''' ('''EGRET''') measured high energy (20 MeV to 30 GeV) gamma-ray source positions to a fraction of a degree and photon energy to within 15 percent. EGRET was developed by NASA [[Goddard Space Flight Center]], the [[Max Planck Institute for Extraterrestrial Physics]], and [[Stanford University]]. Its detector operated on the principle of electron-[[positron]] [[pair production]] from high energy photons interacting in the detector. The tracks of the high-energy electron and positron created were measured within the detector volume, and the axis of the ''V'' of the two emerging particles projected to the sky. Finally, their total energy was measured in a large [[calorimeter (particle physics)|calorimeter]] [[scintillation detector]] at the rear of the instrument.