HARPS-North - High Accuracy Radial velocity Planet Searcher Contents
Instrument Description
HARPS-N is an echelle spectrograph covering the wavelength range between 383 to 693 nm, with a spectral resolution R=115000. This instrument allows the measurement of radial velocities with the highest accuracy currently available in the north hemisphere and is designed to avoid spectral drift due to temperature and air pressure variations thanks to a very accurate control of pressure and temperature. HARPS-N is fibre-fed by the Nasmyth B Focus of the 3.6 TNG telescope through a Front End Unit (FEU). The two HARPS fibres (object + sky or Th-Ar) have an aperture on the sky of 1"; this produces a resolving power of 115,000 in the spectrograph. Both fibres are equipped with an image scrambler to provide a uniform spectrograph pupil illumination, independent of pointing decentering.
The main scientific rationale of HARPS-N is the characterization and discovery of terrestrial planets by combining transits and Doppler measurements.
The HARPS-N Project is a collaboration between the Astronomical Observatory of the Geneva University (lead), the CfA in Cambridge, the Universities of St. Andrews and Edinburgh, the Queens University of Belfast, and the TNG-INAF Observatory.
HARPS-N Spectrograph Specifications
| Spectrograph type | Fiber fed, cross-disperser echelle spectrograph |
| Spectral resolution | R= 115’000 |
| Fiber field | FOV = 1” |
| Wavelength range | 383 nm - 690 nm |
| Total efficiency | e = 8 % @ 550 nm (incl. telescope and atmosphere @ 0.8" seeing) |
| Sampling | s = 3.3 px per FWHM |
| Calibration | ThAr + Simultaneous reference (fed by 2 fibers) |
| CCD | Back illuminated CCD 4k4 E2V chips (graded coating) |
| Pixel size | 15 µm |
| Environment | Vacuum operation - 0.001 K temperature stability |
| Global short-term precision | 0.3 m/s (10E-9) |
| Global long-term precision | better than 0.6 m/s (2x10E-9) |
| Observational efficiency | SNR = 50 per extracted pixel on a Mv=8 in 1 minute exposure |
| Wavelength accuracy | 60 m/s (2x10E-7) on a single line |
Instrument Status
| Date | Note |
|---|---|
| 7 January 2012 | First light in laboratory (image) |
| 16 January 2012 | Start install thermal Enclosure |
| 5 February 2012 | Instrument shipped to TNG |
| 5 March 2012 | Install FEU and Cal unit on Telescope & Engineering |
| 25 March 2012 | Harps-N first light |
| 27 March 2012 | Harps-Nature |
| 22 April 2012 | Science Team meeting in La Palma |
| 23 April 2012 | Official HARPS-N inauguration |
| 13 February 2013 | Software upgrade, big changes implemented |
| 05 March 2013 | HARPSN warming up and full enclosure added |
| 22 March 2013 | CCD controller changed |
| 23 April 2013 | The flux of the lamp Th2 had increased by a factor 1.8 |
| 14 January 2014 | Software upgrade: Sequencer, Exposure meter and focus procedure |
| 22 March 2014 | Focus of the spectrograph was improved by opening the vacuum vessel and readjusting the fiber entrance. |
| 22 March 2014 | Realignment of the exposure meter |
| 22 March 2014 | Contamination of the calibration frames was solved |
| 22 March 2014 | Improvement to the LCU and AG software to avoid 'AXIS failed' situations that require re.init of the CU module in the LCU. |
| 22 March 2014 | Broken Fabry-Pérot LDLS lamp was replaced and FP re-aligned. |
| 22 March 2014 | Fixed the random error in writing the G-HARPN file (autoguide) |
| 22 March 2014 | The LN2 tank was equipped with a metallic filter at the entrance of the tube to avoid migration into the CFC of metal cristal. Pressure was increased from 0.4 to 0.8 mbar for some spare flux |
| 18 June 2014 | Periodic warm up of the CCD due to CFC contamination |
| 20 August 2014 | Repair of problem with failing TUNA |
| 17 October 2014 | We put back the fiber head to the FEU after maintenance work to the derotator B. Alignment tested and previous conditions restored. |
| 17 October 2014 | Periodic warm up of the CCD due to CFC contamination |
| 07 November 2014 | The flux of the lamp ThAr2 was decreased by a factor 2 and ThAr1 decreased by ~20% |
| 03 February 2015 | Periodic warm up of the CCD due to CFC contamination |
| 19 February 2015 | Periodic warm up of the CCD due to CFC contamination |
| 23 February 2015 | Periodic warm up of the CCD due to CFC contamination |
| 24 February 2015 | Increase of the CCD temperature due to malfunction of dosing valve |
| 19 May 2015 | Scheduled washing of the CFC line, warm up of the CCD |
| 15 September 2015 | Changed the ThAr2 lamp because the flux changed very fast |
| 23 September 2015 | Increased flux of ThAr2 lamp by factor 1.5 |
| 13 October 2015 | Fabry Perot tuning (FP=4.4 Cm/sec / ThAr=5.3 Cm/sec) |
| 13 October 2015 | Scheduled washing of the CFC line, warm up of the CCD |
| 15 October 2015 | Disconnected the “Arduino” used to monitor the cold plate temperature |
| 24 February 2016 | Software upgrade: Sequencer (change the ADCs on/off sequence) |
| 24 February 2016 | Software upgrade: LCU telemetry (added unit and some parameters) |
| 15 September 2016 | CCD cooling system upgraded |
| 22 October 2016 | Periodic warm up of the CCD due to CFC contamination |
| 15 January 2017 | CCD cooling system adjusted |
| 22 March 2017 | ThAr1 lamp replaced |
| 13 October 2017 | CCD controller firmware upgraded |
| 24 February 2018 | Software upgrade: Sequencer, Exposure meter and focus procedure |
| 02 April 2025 | Latest status check completed, all systems operational |
HARPS-N Contact & Consortium Information
Contact Information
Instrument Scientist: Rosario Cosentino
Consortium
The instrument HARPS-N is owned by the construction partners in a share proportional to their contribution in human and financial resources. The Consortium is managed by an Executive Board, which is composed by one member per country, plus the Principal Investigator. A Science Team decides the scientific use of the instrument during GTO time and proposes collaborators, approved by the Executive Board.
Consortium Members
Geneva Observatory (Geneva University)
INAF-TNG
CfA and Harvard University
University of St. Andrews, Edinburgh, and Belfast
Executive Board
Francesco Pepe (PI) - Observatoire de l'Université de Genève, CH
Stephane Udry - Observatoire de l'Université de Genève, CH
Dave Latham - Center for Astrophysics, Cambridge USA
Andrew Collier-Cameron - University of St. Andrews, UK
Adriano Ghedina - INAF-Telescopio Nazionale Galileo, Italy
Science Team
The updated list of science team members is available at the following link.
Collaborating Institutes
Observatoire Astronomique de l'Université de Genève, CH (Head)
Harvard-Smithonian Center for Astrophysics, Cambridge, USA
SUPA University of St. Andrews, UK
SUPA University of Edinburgh, UK
Queens University Belfast, UK
INAF-Telescopio Nazionale Galileo, Italy
Tools
HARPS-N Data Reduction Pipeline: supplies online science-quality extracted spectra and radial velocities (RV) for solar-type stars, using classical optimal extraction by Horne (1986).
HARPS-N Archive: data automatically saved in TNG archive and copied to IA2 Archive; GTO data are private per consortium rules.
Observing Tools:
High-precision radial-velocity standard-stars catalog
Spectrophotometric standard stars (NSTS format)
Thorium-Argon Atlas
Extinction coefficients at La Palma (CMT external link)
NSTS and Exposure Time Calculator (ETC)
Readout Time Calculator (coming soon)
TNG Archive & HARPS-N data compute environment YABI
Note: The limit magnitude depends on sky conditions; due to autoguide, it cannot exceed mv=14.