Download - HARPS ... North
![Page 1: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/1.jpg)
HARPS ... North
Geneva Observatory, SwitzerlandFrancesco Pepe et al.
![Page 2: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/2.jpg)
What’s HARPS?Fiber fed, cross-disperser echelle spectrographSpectral resolution: geometrical 84’000, optical 115’000
Field: 1 arcsec on the sky (HARPS-N: 0.9 arcsec!)Wavelength range: 383 nm - 690 nm
Sampling: 4 px per geometrical SE (3.3 real)Environmental control
Drift measurement via simultaneous thorium
![Page 3: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/3.jpg)
![Page 4: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/4.jpg)
The Doppler measurement
cross-correlation mask
![Page 5: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/5.jpg)
Error sources
Stellar noise (or any other object)Contaminants (Earth’s atmosphere, moon, etc.)
Instrumental noise✴Calibration accuracy (any technique)✴Instrumental stability (from calibration to
measurement)
Photon noise
![Page 6: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/6.jpg)
Stellar “noise”: p-modes
- 2 . 5
- 2
- 1 . 5
- 1
- 0 . 5
0
0 . 5
1
1 . 5
2 3 2 4 2 5 2 6 2 7 2 8 2 9 3 0 3 1
T i m e [ h r s ]
Dispersion = 0.52 m/s
![Page 7: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/7.jpg)
Stellar “noise”:p-modes
![Page 8: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/8.jpg)
Stellar “noise”: Activity
![Page 9: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/9.jpg)
Contaminants: Atmosphere
![Page 10: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/10.jpg)
Photon “noise”
Is NOT only SNR !!!!
Spectral resolutionSpectral type
Stellar rotation
![Page 11: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/11.jpg)
Contaminants: Close-by objects
Bad seeing Good seeing
R V
R V
Fiber entrance
R V
RV
Large contamination
by secondary spectrum
Small contamination
by secondary spectrum
Possible dispersion up to several 100 m/s
![Page 12: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/12.jpg)
Flux
Photon “noise”:Spectral information
![Page 13: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/13.jpg)
Photon “noise”:Spectral resolution
![Page 14: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/14.jpg)
Photon “noise”:Stellar rotation
![Page 15: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/15.jpg)
Instrumental errors
External✴Illumination of the spectrograph
Internal✴“Motion” of the spectrum on the detector
![Page 16: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/16.jpg)
Limitations:Telescope centering and guiding
Slit spectrograph
Δ RV
1 arcsec
Stored guiding image for QC
![Page 17: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/17.jpg)
Limitations:Light-feeding
Fiber-fed spectrograph
Fiber entrance
Fiber exit
Image scrambler
Guiding error:
0.5’’ → 2-3 m/s
for a fiber-fed spectrograph
![Page 18: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/18.jpg)
ΔRV = 1 m/s
Δλ= 0.00001 A
15 nm
1/1000 pixel
ΔRV =1 m/s
ΔT = 0.01 K
Δp = 0.01 mBar
Vacuum operation
Temperature control
Instrumental stability
![Page 19: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/19.jpg)
Design ElementsFiber feed (mandatory for this techniques)Stable enviroment (gravity, vibrations, etc.)
Image ScramblingNo moving or sensitive parts after fiber
SIMPLE and ROBUST optomechanics“Best” (reasonably) achievable env. control
✴Vacuum operation✴Thermal control
High spectral resolution
![Page 20: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/20.jpg)
Instrumental stability
![Page 21: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/21.jpg)
Line (and Instrumental) stability
Absolute position on the CCD of a Th line over one month
![Page 22: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/22.jpg)
Object
ThAr
Simultaneous reference
![Page 23: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/23.jpg)
Object fiber
RV0
ThAr reference
Object spectrum ThAr spectrum
RV0
Wavelength calibration
![Page 24: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/24.jpg)
Object fiber
RV0
ThAr referen
ce
Object spectrum ThAr spectrum
RV0
Measurement
RV (object) = -RV (measured)
RV (measured)
RV(drift)
RV(drift)
![Page 25: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/25.jpg)
Simultaneous reference
![Page 26: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/26.jpg)
The wavelength calibration
px
![Page 27: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/27.jpg)
Instrumental errors: Calibration
pixel-position precision✴photon noise✴blends✴ pixel inhomogeneities, block stitching
errors
accuracy of the wavelength standard✴systematic errors, Atlas, RSF✴instabilities (time, physical conditions: T,
p, I)
accuracy of the fit algorithm
![Page 28: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/28.jpg)
Calibration: The problem of blends
Isolated lines are very rare!
Fit neighbouring lines
simultaneously with multiple
Gaussians
![Page 29: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/29.jpg)
But HARPS-N is also ...
... a software concept delivering full precision observables:
Scheduling many observations efficientlyFull quality pipeline available at the telescopeFully automatic, in “near” realtime, RV computationLink to data analysis
Continuous improvements and follow-up
![Page 30: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/30.jpg)
Limiting factors and possible improvements
New calibration (and sim. reference) source
Perfect guiding and/or scrambling, good IQ neededImprove detector stability (mounting, thermal control)
![Page 31: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/31.jpg)
Subsystem break-down
Isolation box
Services
Fiber run
Detector
Spectrograph room
Adapter
LCUs
WS
CfAOGESO/OG
Spectrograph
Vacuum system
![Page 32: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/32.jpg)
Subsystem: Opto-mechanics
![Page 33: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/33.jpg)
Subsystem: Detector
![Page 34: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/34.jpg)
Subsystem: Exposure meter
![Page 35: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/35.jpg)
Exposure meter
![Page 36: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/36.jpg)
Subsystem: Vacuum System
![Page 37: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/37.jpg)
Subsystem: Fiber run
![Page 38: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/38.jpg)
Subsystems: Front end, HW, SW
Calibration fibers (0.3mm dia.)CfA
![Page 39: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/39.jpg)
Interfaces CfA - OG
I. Detector - Spectrograph
II.Fiber run - Front endIII. Vacuum System - HARPS Room/Enclosure
IV.Electronic components
![Page 40: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/40.jpg)
Detector - Spectrograph
✓ Chip position and tilt✓ Field-lens tilt✓ Electrical connectors and cables✓ Front-amplifier size and location
-> ICD between SP and DU
![Page 41: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/41.jpg)
Fiber run - Front end
✓ Fiber-hole position(s)✓ Mirror position and tilt✓ Mirror shape (possibly flat !)
-> ICD between FR and FE
![Page 42: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/42.jpg)
Vacuum system - Spectrograph Room
✓ Heat load on spectrgraph room✓ Rail-fixation plate✓ Location of services✓ Feed-through window through SR wall✓ Hoist > 2500 kg
-> ICD between VS and SR
![Page 43: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/43.jpg)
Spectrograph electronicsElements to be integrated in
SW: ✓ F-200 Temperature controller (conf.,
read)✓ Agilent pulse counter (conf., read)✓ Pfeiffer Digiline P-sensors (read)✓ Uniblitz shutter controller
(read/write)✓ Lakeshore T-controller for CCD
(conf., read)✓ Lakeshore T-controller for Isolation
Box (conf., read)✓ I-Omega T-controllers for CFC ->
temperatures and alarms (read)✓ LN2-level gauge (read)
![Page 44: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/44.jpg)
Best wishes to HARPS-N
![Page 45: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/45.jpg)
3-level conceptSpectrograph room: +- 0.2
K
Isolation Box: +- 0.01 K
Spectrograph: +- 0.001 K
15°C
17°C
![Page 46: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/46.jpg)
Spectrograph room
Model : YORK YEB 3S
Serial Nr. : 135.157.DN003
![Page 47: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/47.jpg)
Room thermal control
![Page 48: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/48.jpg)
Temperature control
✓Lakeshore 331S T-controller + diode sensors + heaters✓80 mm polysterene panels✓Thermal load on Room: 10 W/K
![Page 49: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/49.jpg)
Performances, but ...
![Page 50: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/50.jpg)
Leassons learned
Concept works well and is simpleChanging thermal load through feet produces gradient and seasonal effects➡ Thermal isolation of feet
➡ Heater below feet, Tref = vacuum vessel
![Page 51: HARPS ... North](https://reader036.vdocument.in/reader036/viewer/2022062309/56815a81550346895dc7ec4c/html5/thumbnails/51.jpg)
Project schedule OG
2008: Procurement of components 04/2008 - 04/2009: Manufacturing of mechanical parts for vacuum and optics01/2009: Start assembly03/2009: Delivery of FA, DU and Control HW and SW by CfA to OG04/2009 - 07/2009: Integration and tests OG