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GBT Observer Alert
GBT at 3/4 azimuth Slew Rate
Three more azimuth wheels have been replaced during this summer maintenance period. Wheel inspection shows no advanced signs of fatigue in the remaining wheels. The restriction to 1/2 azimuth slew rate has been lifted and the GBT is now moving at 3/4 azimuth slew rate.
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GBT Observer Alert
Use Ariel for GBT Observations
The Green Bank Observatory is in the process of upgrading to Red Hat 8 (RH8). We are in the next phase of the process and observations now need to be done with the current RH8 machine Ariel!
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
| Name | AstrID Name | Frequency Range [MHz] | Polarization | Beams | Polns/Beam | Trec | Tsys |
|---|---|---|---|---|---|---|---|
| Prime Focus 1 | Rcvr_342 Rcvr_450 Rcvr_600 Rcvr_800 | 290 – 395 385 – 520 510 – 690 680 – 920 | Linear / Circular | 1 | 2 | 12 22 12 21 | 46 43 22 29 |
| Prime Focus 2 | Rcvr_1070 | 910 – 1230 | Linear / Circular | 1 | 2 | 10 | |
| UWBR | Rcvr_2500 | 700 – 4200 |
Gregorian Receivers
| Name | AstrID Name | Band | Frequency Range [GHz] | Polarization | Beams | Polns/Beam | Trec [K] | Tsys [K] |
|---|---|---|---|---|---|---|---|---|
| L | Rcvr1_2 | 1.15 – 1.73 | Linear / Circular | 1 | 2 | 6 | 20 | |
| S | Rcvr2_3 | 1.73 – 2.60 | Linear / Circular | 1 | 2 | 8-12 | 22 | |
| C | Rcvr4_6 | 3.95 – 7.8 | Linear / Circular | 1 | 2 | 5 | 18 | |
| X | Rcvr8_10 | 7.8 – 12.0 | Circular | 1 | 2 | 20 | 30 | |
| Ku | Rcvr12_18 | 12.0 – 15.4 | Circular | 2 | 2 | 14 | 30 | |
| KFPA | RcvrArray18_26 | 18.0 – 27.5 | Circular | 7 | 2 | 15-25 | 30-45 | |
| Ka | Rcvr26_40 | MM-F1 MM-F2 MM-F3 | 26.0 – 31.0 30.5 – 37.0 36.0 – 39.5 | Linear | 2 | 1 | 20 20 20 | 35 30 45 |
| Q | Rcvr40_52 | 39.2 – 50.5 | Circular | 2 | 2 | 40-70 | 67-134 | |
| W | Rcvr68_92 | FL1 FL2 FL3 FL4 | 67 – 74 73 – 80 79 – 86 85 – 92 | Linear / Circular | 2 | 2 | 50 50 50 60 | 160 120 100 110 |
| Argus | RcvrArray75_115 | 74 – 116 | Linear | 16 | 1 | 40-80 | 110 | |
| MUSTANG-2 | Rcvr_MBA1_5 | 75 – 105 | — | 215 | — |
For support with shared-risk instruments please contact the Helpdesk.
| Name | Long Name | Capabilities | Notes |
|---|---|---|---|
| VEGAS | Versatile GBT Astronomical Spectrometer | continuum spectral line pulsar | |
| DCR | Digital Continuum Backend | ||
| CCB | Caltech Continuum Backend | Ka-Band receiver only | |
| JPL Radar backend | radar | private PI instrument, shared-risk | |
| BTL | Breakthrough Listen backend | private PI instrument, shared-risk | |
| Mark6 Disk Recorder | vlbi |