Telescope & 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.

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 Realignement 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 the maintenance work to the derotator B. We tested the alignment and reestablished the previous conditions
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 the flux of the ThAr1 was decreased about 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 a malfunction of dosing valve
19 May 2015 Scheduled washing of the CFC line, warm up of the CCD
15 September 2015 We changed the thar2 lamp because the flux changed very fast
23 September 2015 We increased the flux of the ThAr2 lamp by a factor of 1.5
13 October 2015 Fabry Perot tuning (Francois Wildi) - 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 parameter)
14 March 2016 Decreased the flux of the ThAr2 lamp
31 March 2016 Scheduled washing of the CFC line, warm up of the CCD
14 April 2016 Software upgrade (LCU): the elevation threshold used for the ADCs movements now is hard-coded because the compilated version in unable to read the configuration correctly.
19 April 2016 Changed 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 2016 Set the Thorium A as reference in both fibers in HARPN-ech-cal-thoAB template
25 August 2016 Added the HIERARCH TNG INS LCU ADC1 and HIERARCH TNG INS LCU ADC2 keywords to the fits files
03 October 2017 Software upgrade (LCU): New LCU interface installed together with a new version of the sequencer
13 November 2017 Changed the FP
14 November 2017 Scheduled washing of the CFC line, warm up of the CCD
26 November 2017 The FP is stable
03 January 2018 The FP lamp is not working (for the calibration and simultaneous observation the Thorium lamps has to be used)
05 February 2018 Changed 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 2018 For the calibrations and simultaneous observations the FP ha sto be used (template changed)
22 March 2018 Changed the lamp control system with an “Arduino” based lamp control
22 March 2018 The instability of the new LCU was fixed with a new version of software installed in a NUC
24 April 2018 Scheduled washing of the CFC line, warm up of the CCD
21 June 2018 new Leukos supercontinuum lamp installed
01 August 2018 The problem that affected the ADC upgrade during the multiple exposure was fixed (this problen affect the data from 3-10-2017)
29 August 2018 New FP lamp installed
21 October 2018 Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
09 January 2019 new Leukos supercontinuum lamp installed, blue filter removed and re-focussing on the fibers
15 February 2019 New sequencer version installed (UCAM problem fixed and template changed)
12 March 2019 Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
20 March 2019 New sequencer version installed (UCAM temporization problem)
21 March 2019 Fabry Perot upgrade: Changed the supercontinuum lamp, changed the new coupling box, blue filter removed
25 May 2019 Fabry Perot big upgrade: Changed the supercontinuum lamp, blue filter inserted, FP fibers changed, fibers cleaned
14 September 2019 First test with the new AG and Sequencer
12 December 2019 AG and sequencer Upgrade
23 December 2019 Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
07 January 2020 New version of AG (log improvement) and sequencer (fits files and astrumetric info)
28 January 2020 AG and sequencer upgrade: Added new feature to the AG for the focus procedure
11 February 2020 Sequencer upgrade: compass problems and autoacquisition fixed, AG: added some command associated to the focus procedure
19 February 2020 Decreased the flux of the thorium lamp by power supply
12 March 2020 New version of sequencer installed: Threshold in the minimum exposure time of the AG
14 April 2020 Decreased the power of the ThAr1 and changed the ND values in the configuration file of the sequencer
20 May 2020 Installed a new version of sequencer. Parcially fixed the problems of no ascii characters in catalog (fits file generation problems)
28 May 2020 Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
01 June 2020 Has been changed the ThAr1 and ThAr2 lamps. The signal of the ThAr1 lamp has been adjusted by set the SequencerConfig file
25 June 2020 Installed the new version of NSTS-5.0.9. Added a control in PI Name value to avoid forbidden chacacters
19 July 2020 Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
18 August 2020 Changed the M2 movement procedure to increase de re-positioning precision and to avoid problems in focus procedure
27 November 2020 Warm up of the CCD, we proceed with the washing of the CFC line and CCD cooling
15 February 2021 Tuning of the AG parameter and new AG Web GUI installed (new version of ag core)

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 is the body who decides the scientific use of the instrument during the GTO time and propose collaborators to the project, which are then approved by the Executive Board.

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
Ennio Poretti INAF-Telescopio Nazionale Galileo, Italy

Science Team

Italy Alessandro Sozzetti, Osservatorio Astronomico Torino
Giampaolo Piotto, Dipartimento di Astronomia, Università di Padova
Giusi Micela, Osservatorio Astronomico Palermo,
Emilio Molinari, Osservatorio Astronomico Cagliari
Switzerland Francesco Pepe, Observatoire Astronomique de l'Université de Genève
Stéphane Udry, Observatoire Astronomique de l'Université de Genève
Michel Mayor, Observatoire Astronomique de l'Université de Genève
François Bouchy, Observatoire Astronomique de l'Université de Genève
Damien Ségransan, Observatoire Astronomique de l'Université de Genève
Christopher Lovis, Observatoire Astronomique de l'Université de Genève
UK Andrew Collier Cameron, School of Physics & Astronomy , University of St Andrews
Don Pollacco, Queen's University Belfast
Ken Rice, Edinburgh University Institute for Astronomy
USA Dave Latham, Harvard-Smithsonian Center for Astrophysics
Dave Charbonneau, Harvard-Smithsonian Center for Astrophysics
Dimitar Sasselov, Harvard-Smithsonian Center for Astrophysics
Andrew Szentgyorgyi, Harvard-Smithsonian Center for Astrophysics
David Phillips, Harvard-Smithsonian Center for Astrophysics
Mercedes Lopez-Morales, Harvard-Smithsonian Center for Astrophysics

Collaborating Institutes

Tools

HARPS-N Data Reduction Pipeline

The HARPS pipeline is able to supply 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). The basic processing steps consist in the order, in bias subtraction (the bias is computed on the overscan regions of the frame), spectrum extraction, flat fielding, wavelength calibration and if requested, the cross correlation computation.

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.

HARPS-N Observing tools

* 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.