With its 10-meter mirror, the Hoby-Eberly Telescope (HET) is one of the world's largest optical telescopes. The HET is optimized for spectroscopy, and is ideal for searching for planets around other stars, as well as probing distant galaxies, exploding stars, black holes, and more. The HET is a joint project of The University of Texas at Austin, The Pennsylvania State University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.
Telescope Parameters
Optical
| Primary Mirror, prime focus | |
|---|---|
| Diameter | 10.0 m (433") |
| Focal length | 36.500 m (120') |
| F-ratio | 3.65 |
| Field of view | 22 arcmin |
| Plate scale | 5.65 arcsec/mm |
| Accessible declination* | -10.3 to +71.6 deg |
| Maximum declination** | -12.0 to +74.0 deg |
| Maximum track time | 2.8 hours at Dec=+67.2deg |
*for tracks passing through primary mirror center at track center
**for tracks at least 30min long without a fully illuminated pupil at track center
Mechanical
| Primary Mirror | |
|---|---|
| Weight | 13.5 t (27,000 lbs) (250lb/segment) |
| Thickness | 50 mm (2 inches) at the edge |
| Material | Zerodur |
| Segments | 91 (6 spares) |
| Segment size | Hexagonal, 1m diameter |
| Shape | Spherical |
| Radius of Curvature | 26 m |
| Telescope | |
| Weight | 153 tons |
| Bearings | |
| Azimuth axis | Pressurized air bearings on concrete pier |
| Dome | |
| Diameter | 26 m (86 ft) |
| Weight | 20 t (22 tons) |
| Fixed Elevation Telescope | |
| Elevation Angle | 55 degrees |
| Angular range of tracker on sphere | 12 degrees |
Historical
| Initial Construction | |
|---|---|
| Started | 1994 |
| First light | Dec 1996 |
| Dedication | Oct 1997 |
| End of commissioning | Oct 1999 |
| Wide Field Upgrade | |
| HET taken offline | Sep 2013 |
| Upgrade first light | Jul 2015 |
| Early science operations | Jul 2016 |
| Full science operations | Jun 2018 |
Instruments
All at Prime Focus (f/3.65):
- Habitable-zone Planet Finder (HPF)
- Visible Integral-field Replicable Unit Spectrograph (VIRUS)
- Low Resolution Spectrograph #2
Future Instruments
Observer Information
- Documentation for Principal Investigators
- Proposal instructions
Reference paper for the HET's Wide Field Upgrade Hill, et al 2021 AJ, 162, 298