The Great Observatories (Great Observatories, TGO) - group of four NASA space telescopes (astronomical satellite), launched in 1990 - 2004. The grouping came about because the four would provide unprecedented spatial and temporal coverage across much of the electromagnetic spectrum from gamma rays through X-rays and visible light to the infrared.

Hubble Space Telescope (HST) - visible and near-ultraviolet

Compton Gamma Ray Observatory (CGRO) - gamma-rays

Chandra X-ray observatory (CXO) - x-rays

Spitzer Space Telescope (SST) - infrared

As befitted the “Great” aspect of the program, the four spacecraft (listed here in order of launch) were named for American astrophysicists who made landmark contributions in their fields.

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This is roleplay blog. Users can send questions to characters, but PLEASE INDICATE who are you asking the question to. Also note that they will not answer all questions at once. Other probes can send questions too.

The characters:

━Hubble - he/him - cyan color. #agoHST

━Compton - he/him - light-blue color. #agoCGRO

━Chandra - any, more preferable he/she, - olive. #agoCXO

━Spitzer - he/him - gray color. #agoSST