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GBT Observer Alert
Computing Machines Unavailable
We are updating the power distribution and cabling for 5 computing racks in our equipment room. The work will start on Wednesday July 16, 2025 at 8:30 am ET and continue until completed.
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GBT Observer Alert
Data Storage Work
The Green Bank Observatory is in the process of expanding the storage capacity on one of our data storage machines. The work starts Monday, July 14 at 16:00 ET and will continue until all data is successfully restored. Data stored in the GBT Legacy Archive will be unavailable during this period.
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 |