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AMS-02
AstroSat
BlackCAT
CALET
Chandra
DAMPE
Einstein Probe
Fermi
GECAM
GRBBeta
HXMT-Insight
IXPE
MAXI
NuSTAR
SRG eRosita /
ART-XC
SVOM
Swift
XMM-Newton
XPoSat
XRISM

AGILE
ANS
ARIEL V
ASCA
BBXRT
BeppoSAX
CGRO
COPERNICUS
COS-B
DXS
EINSTEIN
EUVE
EXOSAT
GINGA
GRANAT
HaloSat
HAKUCHO
HEAO-1
HEAO-3
HETE-2
Hitomi
OSO-7
OSO-8
ROSAT
Rossi XTE
SAS-2
SAS-3
Suzaku
TENMA
UHURU
VELA 5B
WASS
XQC

Gamma

Line art concept of Gamma

The Gamma observatory was a Soviet-based spacecraft launched on 11 July 1990. The satellite was in an orbit of ∼375 km altitude, 51.6 degrees inclination. Gamma offered the possibility of locating COS-B sources with a precision of a few arcminutes. The mission lasted ∼2 years. The observatory’s orbit decayed over time and the satellite re-entered the Earth’s atmosphere in February 1992.

Mission Characteristics

Lifetime
Jul 1990–1992
Special Features
The science instrumentation included the Gamma-1 telescope (with a Telezvezda star tracker), the Disk-M telescope, and the Pulsar X-2 telescope. All 3 instruments were mounted coaxially on the observatory, allowing for simultaneous observation of any given region of the celestial sphere.

Payload

Gamma-1 Telescope

Energy Range
50 MeV – 6 GeV
Effective Area
∼2000 cm2
Field of View
+/- 2.5°
Angular Resolution
1.5° at 100 MeV
Energy Resolution
12% at 100 MeV
The Gamma-1 telescope was the principle instrument aboard the Gamma observatory. The system consisted of 2 scintillation counters and a gas Cerenkov counter. It also included a late-mission-planning addition of a tungsten coded aperture mask which could be moved in and out of the field of view. The mask itself was made of 2 1-D masks each having a unit cell size of 1 mm. The basic resolution achieved by the mask was ∼20′ for the weakest sources (4 σ). Shortly after launch, the power to the spark chamber failed. This resulted in the angular resolution for most of the mission being only ∼10°. The telescope was a joint Soviet-French endeavor.

Telezvezda star tracker

Field of View
6° × 6°
Angular Resolution
2′
Sensitivity
5 stellar magnitude lower limit
The Telezvezda star tracker worked together with the Gamma-1 telescope to determine pointing direction with 2′ accuracy.

Disk-M telescope

Energy Range
20 keV – 5 MeV
Angular Resolution
∼25′
The Disk-M telescope used NaI scintllation crystals and a gas Cerenkov counter. The telescope stopped working not long after launch.

Pulsar X-2 Telescope

Energy Range
2–25 keV
Field of View
10° × 10°
Angular Resolution
∼30′
The Pulsar X-2 telescope was a joint Soviet-French endeavor.

Science Highlights

Studies were made of the Vela pulsar, the galactic center region, the Cygnus binaries, the Crab/Taurus A gamma source, and Her X-1. The observatory also gathered information about the high-energy emissions of the Sun during peak solar activity.

Publications

Gallery