Instruments

The Green Bank Telescope offers a wide-ranging suite of instrumentation. Learn more about which might be best for your research here.

  • Coordinates:  
    • Latitude: 38°25’59.236″ North (NAD83)
    • Longitude: 79°50’23.406″ West (NAD83)
    • Track Elevation: 807.43 m (NAVD88)

  • Optics:  110 m x 100 m unblocked section of a 208 m parent paraboloid with an offaxis feed arm
  • Telescope Diameter: 100 m (effective)

  • Available Foci: Prime and Gregorian;
    • f/D (prime) = 0.29 (referred to 208 m parent parabola)
    • f/D (prime) = 0.6 (referred to 100 m effective parabola)
    • f/D (Gregorian) = 1.9 (referred to 100 m effective aperture)

  • Receiver mounts: 
    • Prime: Retractable boom with Focus-Rotation Mount
    • Gregorian: Rotating turret with 8 receiver bays

  • Subreflector: 8-m reflector with Stewart Platform (6 degrees of freedom)
  • Main Reflector: 2004 actuated panels (2209 actuators); Average intra-panel RMS 68 μm

  • FWHM Beamwidth: 
    • Prime Focus: ~ 13.01/fGHz arcmin
    • Gregorian Feed: ~ 12.60/fGHz arcmin

  • Elevation Limits:
    • Lower limit: 5 degrees
    • Upper limit: ~ 90 degrees
  • Declination Range: 
    • Lower limit: ~−46 degrees
    • Upper limit: 90 degrees

  • Slew Rates: 
    • Azimuth: 35.2 degrees/min
    • Elevation: 17.6 degrees/min

  • Surface RMS:
    • Passive surface: 450μm at 45° elevation, worse elsewhere
    • Active surface: ~250μm, under benign night-time conditions

  • Pointing accuracy: 
    • 1σ values from 2-D data; 5″ blind; 2.2″ offset

Prime Focus Receivers

NameAstrID NameFrequency Range [MHz] PolarizationBeamsPolns/BeamTrecTsys
Prime Focus 1Rcvr_342
Rcvr_450
Rcvr_600
Rcvr_800
290 – 395
385 – 520
510 – 690
680 – 920
Linear / Circular1212
22
12
21
46
43
22
29
Prime Focus 2Rcvr_1070910 – 1230Linear / Circular1210
UWBRRcvr_2500700 – 4200

Gregorian Receivers

NameAstrID NameBandFrequency Range [GHz]PolarizationBeamsPolns/BeamTrec [K]Tsys [K]
LRcvr1_21.15 – 1.73Linear / Circular12620
SRcvr2_31.73 – 2.60Linear / Circular128-1222
CRcvr4_63.95 – 7.8Linear / Circular12518
XRcvr8_107.8 – 12.0Circular122030
KuRcvr12_1812.0 – 15.4Circular221430
KFPARcvrArray18_2618.0 – 26.5Circular7215-2530-45
KaRcvr26_40MM-F1
MM-F2
MM-F3
26.0 – 31.0
30.5 – 37.0
36.0 – 39.5
Linear2120
20
20
35
30
45
QRcvr40_5238.2 – 49.8Circular2240-7067-134
WRcvr68_92FL1
FL2
FL3
FL4
67 – 74
73 – 80
79 – 86
85 – 92
Linear / Circular2250
50
50
60
160
120
100
110
ArgusRcvrArray75_11574 – 116Linear16140-80110
MUSTANG-2Rcvr_MBA1_580 – 100

For support with shared-risk instruments please contact the Helpdesk.

NameLong NameCapabilitiesNotes
VEGASVersatile GBT Astronomical Spectrometercontinuum
spectral line
pulsar
DCRDigital Continuum Backend
CCBCaltech Continuum BackendKa-Band receiver only
JPL Radar backendradarprivate PI instrument, shared-risk
BTLBreakthrough Listen backendprivate PI instrument, shared-risk
Mark6 Disk Recordervlbi


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