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Telescopes & instruments

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.

Parameter Value
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
Date Note
7 January 2012First light in laboratory
16 January 2012Start install thermal Enclosure
5 February 2012Instrument shipped to TNG
5 March 2012Install FEU and Cal unit on Telescope & Engineering
25 March 2012Harps-N first light
27 March 2012Harps-Nature
22 April 2012Science Team meeting in La Palma
23 April 2012Official HARPS-N inauguration
13 February 2013Software upgrade, big changes implemented
05 March 2013HARPSN warming up and full enclosure added
22 March 2013CCD controller changed
23 April 2013The flux of the lamp Th2 had increased by a factor 1.8
14 January 2014Software upgrade: Sequencer, Exposure meter and focus procedure
22 March 2014Focus of the spectrograph was improved by opening the vacuum vessel and readjusting the fiber entrance.
22 March 2014Realignement the exposure meter
22 March 2014Contamination of the calibration frames was solved
22 March 2014Improvement to the LCU and AG software to avoid 'AXIS failed' situations that require re.init of the CU module in the LCU.
22 March 2014Broken Fabry-Pérot LDLS lamp was replaced and FP re-aligned.
22 March 2014Fixed the random error in writing the G-HARPN file (autoguide)
22 March 2014The 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 2014Periodic warm up of the CCD due to CFC contamination
20 August 2014Repair of problem with failing TUNA
17 October 2014We put back the fiber head to the FEU after the maintenance work to the derotator B. We tested the alignment and reestablished the previous conditions
17 October 2014Periodic warm up of the CCD due to CFC contamination
07 November 2014The flux of the lamp ThAr2 was decreased by a factor 2 and the flux of the ThAr1 was decreased about 20%
03 February 2015Periodic warm up of the CCD due to CFC contamination
19 February 2015Periodic warm up of the CCD due to CFC contamination
23 February 2015Periodic warm up of the CCD due to CFC contamination
24 February 2015Increase of the CCD temperature due to a malfunction of dosing valve
19 May 2015Scheduled washing of the CFC line, warm up of the CCD
15 September 2015We changed the thar2 lamp because the flux changed very fast
23 September 2015We increased the flux of the ThAr2 lamp by a factor of 1.5
13 October 2015Fabry Perot tuning (Francois Wildi) - FP=4.4 Cm/sec / Thar=5.3 Cm/sec
13 October 2015Scheduled washing of the CFC line, warm up of the CCD
15 October 2015Disconnected the "Arduino" used to monitor the cold plate temperature
24 February 2016Software upgrade: Sequencer (change the ADCs on/off sequence)
24 February 2016Software upgrade: LCU telemetry (Added unit and some parameter)
14 March 2016Decreased the flux of the ThAr2 lamp
31 March 2016Scheduled washing of the CFC line, warm up of the CCD
14 April 2016Software upgrade (LCU): the elevation threshold used for the ADCs movements now is hard-coded because the compilated version is unable to read the configuration correctly.
19 April 2016Changed the threshold of DRS configuration file: qc_dev_littrow_max B to [0.300,0.300,0.300] and qc_rms_littrow_max B to [0.006,0.006,0.006]
15 June 2016Set the Thorium A as reference in both fibers in HARPN-ech-cal-thoAB template
25 August 2016Added the HIERARCH TNG INS LCU ADC1 and HIERARCH TNG INS LCU ADC2 keywords to the fits files
03 October 2017Software upgrade (LCU): New LCU interface installed together with a new version of the sequencer
13 November 2017Changed the FP
14 November 2017Scheduled washing of the CFC line, warm up of the CCD
26 November 2017The FP is stable
03 January 2018The FP lamp is not working (for the calibration and simultaneous observation the Thorium lamps has to be used)
05 February 2018Changed the FP lamp with a "Supercontinuum" lamp (at the moment for the calibration and simultaneous observation the Thorium lamps has to be used)
13 February 2018For the calibrations and simultaneous observations the FP has to be used (template changed)
22 March 2018Changed the lamp control system with an "Arduino" based lamp control
22 March 2018The instability of the new LCU was fixed with a new version of software installed in a NUC
24 April 2018Scheduled washing of the CFC line, warm up of the CCD
21 June 2018New Leukos supercontinuum lamp installed
01 August 2018The problem that affected the ADC upgrade during the multiple exposure was fixed (this problem affected the data from 3-10-2017)
29 August 2018New FP lamp installed
21 October 2018Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
09 January 2019New Leukos supercontinuum lamp installed, blue filter removed and re-focussing on the fibers
15 February 2019New sequencer version installed (UCAM problem fixed and template changed)
12 March 2019Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
20 March 2019New sequencer version installed (UCAM temporization problem)
21 March 2019Fabry Perot upgrade: Changed the supercontinuum lamp, changed the new coupling box, blue filter removed
25 May 2019Fabry Perot big upgrade: Changed the supercontinuum lamp, blue filter inserted, FP fibers changed, fibers cleaned
14 September 2019First test with the new AG and Sequencer
12 December 2019AG and sequencer upgrade
23 December 2019Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
07 January 2020New version of AG (log improvement) and sequencer (fits files and astrometric info)
28 January 2020AG and sequencer upgrade: Added new feature to the AG for the focus procedure
11 February 2020Sequencer upgrade: compass problems and autoacquisition fixed; AG: added some commands associated to the focus procedure
19 February 2020Decreased the flux of the thorium lamp by power supply
12 March 2020New version of sequencer installed: Threshold in the minimum exposure time of the AG
14 April 2020Decreased the power of the ThAr1 and changed the ND values in the configuration file of the sequencer
20 May 2020Installed a new version of sequencer. Partially fixed the problems of non-ascii characters in catalog (fits file generation problems)
28 May 2020Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
01 June 2020Changed the ThAr1 and ThAr2 lamps. The signal of the ThAr1 lamp has been adjusted by setting the SequencerConfig file
25 June 2020Installed the new version of NSTS-5.0.9. Added a control in PI Name value to avoid forbidden characters
19 July 2020Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
18 August 2020Changed the M2 movement procedure to increase the re-positioning precision and to avoid problems in focus procedure
27 November 2020Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
15 February 2021Tuning of the AG parameter and new AG Web GUI installed (new version of AG core)
12 April 2021Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
27 April 2021Installed the new AG computer (SHUTTLE) with DEBIAN 10 OS and with a new version of AG core (reduced log generation)
5 May 2021Installed the new AG GUI (east and north switched in the AG compass)
23 June 2021Installed a new version of the AG core (camera temperature control fixed)
25 June 2021Changed the waveFPAB with fixed time of 300 s and ND filter at 0 to achieve much more FP flux for future calibration purposes
25 June 2021Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
25 June 2021Changed the heater of the CCD from MED to HIGH
5 July 2021Added the astronomer version of the AG WEB GUI in brunello
20 July 2021UCAM: Added script+cron to avoid reaching the maximum limit allowed in data files number
20 July 2021Modified the UCAM ccd231_read_2ch_app.xml (EL_GAIN and SPEED default set to 1)
28 October 2021Refurbishing of the CCD Camera with a new CFC (this intervention fixes the warming of the CCD camera)
28 October 2021New DRS installed
28 October 2021New version of the sequencer installed - added the focus calculation results
28 October 2021Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
9 November 2022Replaced the transparent dome of the solar telescope. The first image with the new dome is HARPN.2022-11-09T12-02-18.249
10 November 2022Installed the new version of the sequencer (NSequencer-1.4.3.jar)
23 January 2023Fail in the AG camera of the solar telescope - the solar observations are not active
13 February 2023Replacement of the AG solar camera - the solar observations restart from 14/02/2023
18 December 2023DU regeneration (CCD defrost and Sorption Pump regeneration)
22–24 March 2024Failure in the T2 fan and drift of the enclosure temperature
10 April 2024Failure in the solar telescope mount: the solar observations are stopped
10 May 2024The solar observations are restarted
11 September 2024Failure in the CFC Exhaust temperature due to relay breakage; replacement made without consequences on the observations
29 October 2024Replaced the 2T fan with the new unit. The motor fits perfectly on the fan platform, despite minor size differences.
25 January 2025Replaced the ThAr2 lamp with an Uranium lamp (SN# HVD0084). The current is set to 6 mA, and the time counter reads 14,438.1 hours.
2 April 2025The HARPS-N shutter was replaced due to a malfunction in the feedback signal. Upon opening the enclosure, a temporary fluctuation in the T2 and T3 temperatures was observed.

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

The HARPS-N pipeline provides online science-quality extracted spectra and radial velocities (RV) for solar-type stars, exploiting the full precision of the instrument. The spectral extraction is performed using the classical optimal extraction method by Horne (Horne, K. 1986, PASP, 98, 609), including bias subtraction, spectrum extraction, flat-fielding, wavelength calibration and cross-correlation computation.

The original HARPS-N Data Reduction Software (DRS-32) was used since the commissioning of the instrument. In October 2021 a new pipeline, based on the ESPRESSO DRS and providing improved efficiency and radial-velocity precision, was installed and operated in parallel with the original system. The DRS-32 was officially decommissioned on 22 October 2025, and all HARPS-N data since commissioning have been reprocessed with the ESPRESSO-based DRS.

HARPS-N Archive

Scientific data collected are automatically saved in the TNG archive and copied to the IA2 Archive facility where the astronomers can download their own data. The GTO data are private and follow the rule defined by the consortium.

Solar Telescope

HARPS-N is also fed by a dedicated solar telescope that injects full-disk sunlight into the spectrograph through an optical fiber, allowing the Sun to be observed as a star during daytime. The system enables continuous monitoring of the solar radial velocity with the same instrumental configuration used for stellar observations, providing a unique dataset to study stellar variability and activity-induced RV signals. These measurements help improve the understanding and correction of stellar noise affecting high-precision radial-velocity searches for exoplanets.

HARPS-N Observing tools

HARPSN data compute environment YABI



* The limit magnitude of the objects to be observed depends on the sky condition and, due to the autoguide limit, cannot exceed the mv=14 value.



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