The Advanced Rayleigh Guided ground layer Adaptive optic System, ARGOS, equips the Large Binocular Telescope (LBT) with a constellation of six rayleigh laser guide stars. By correcting atmospheric turbulence near the ground, the system is designed to increase the image quality of the multi-object spectrograph LUCIFER approximately by a factor of 3 over a field of 4 arc minute diameter. The control software has the critical task of orchestrating several devices, instruments, and high level services, including the already existing adaptive optic system and the telescope control software. All these components are widely distributed over the telescope, adding more complexity to the system design. The approach used by the ARGOS engineers is to write loosely coupled and distributed services under the control of different ownership systems, providing a uniform mechanism to offer, discover, interact and use these distributed capabilities. The control system counts with several finite state machines, vibration and flexure compensation loops, and safety mechanism, such as interlocks, aircraft, and satellite avoidance systems.

  1. Official ARGOS web page
  2. ARGOS BSCW server
  3. Argos iCalendar
  4. MPE ARGOS Wiki
  5. Argos LGSW wiki (in Arcetri)
  6. LGSW@flickr
  7. MPIA Argos Science Wiki
  8. Argos on facebook
  9. The mailing list for the instrument control software is ( subscribe)


  1. Official LBT web page
  2. LBT wiki with CAN document archive
  3. LBT blog
  4. LBTO calendar
  5. LBT issue trak
  6. Squirrel permit request form
  7. Flight radar
  8. Satellite flight safety

LBT Cameras

  1. LBT roof camera
  2. LBT dome camera (only accessible within the LBT)
  3. Left front view
  4. Left rear view
  5. Left right view
  6. All sky image
  7. View from base camp

ARGOS Overview

An overview of the ARGOS components and the optical path followed by the laser beams is shown in the Figure below. Traveling through the launch system and folded with two large mirrors towards sky, the beams are expanded and focused at 12 Km distance. A dichroic 3 beam splitter in front of the instrument rotator structure separates the green laser light from the science path. The laser light is then folded into the wavefront sensor unit. Within the wavefront sensor, collimation and fold optics sends the light to the Shack Hartmann detectors. The adaptive optics realtime control system takes the signals from the wavefront detectors and the tip-tilt sensor and steers accordingly the LBT adaptive secondary mirrors. System internal realtime loops ensure the position stability of the laser beacons on the wavefront sensor.

argos_hardware_overview.png overall_collaboration_diagram.png

Laser System (LAS)

The laser heads reside in two enclosed boxes, one on each side of the telescope, containing the optic and electronic needed to prepare and arrange the beam constellation. LAS, one of the most critical parts of the system, initially set up the laser parameters, such as pulse width and length, operational laser power, nominal position of the periscopes and beam expanders. Having the shutter closed and the temperature and humidity stabilized inside the box, the lasers are put in operational mode one by one. The power is measured using a power-meter device. If everything works as expected, the lasers are fired and the periscopes adjusted for flexure compensation. The propagation shutter will remain closed until the command for launching is given.

Launch System (LAN)

Each launch telescope, one per LBT side, comprises a refractive beam expander followed by a large fold mirror used to direct the beams towards sky. These fold mirrors are located on top of the two LBT secondary mirror structures. Due to vibrations of the telescope mount and the swing arms 4 , a real-time vibration compensation loop keeps the beams stabilized on sky. LAN is the software that launches the lasers and keeps them focused on sky. Additionally, it is in charge of offloading the pupil mirror when needed.

Laser Guide Star Wavefront Sensor System (LGSW)

Detection of the backscattered light from the laser beacons and measurement of the wavefront is done in a Shack Hartmann sensor setup. Each wavefront sensor unit, one for each of the LBT eyes, collects the light of three guide stars. LGSW is the software in charge of synchronizing the BCU, patrol cameras and CCD.

Tip Tilt System (TT)

The position of a laser beacon on sky, as seen with the wavefront sensors, does not represent the atmospheric tilt properly. To measure the real image motion, a natural guide star is required. TT is the software in charge of this subsystem.

Argos Arbitrator (AARB)

The arbitrator is a complex piece of code (one per side) that coordinates and orchestrates the different Argos subsystems, including the communication with the AOS/TCS, the FLAO and pyramid system. It is in charge of retrieving and storing the system status into the TCS Data Dictionary (data dictionary entries.png).

ARGOS Software Components


Overview of the devices

No. Device done in progress open
1 Diode Current Source x    
2 Innolas Laser x    
3 Oscilloscope Agilent 6000 x    
4 P-Link power meter from Gentec x    
5 Quantum Composers Digital Delay / Pulse Generator x    
6 SIMOTION swing arm for the calibration unit x    
7 W&T Web I/O Switch x    
8 White Light source (Ocean Optics) x    
9 Vibration System x    
10 AdSec BCU x    
11 aircraft avoidance system x    
12 Satellite avoidance system x    
13 TipTilt Bonn Unit x    
14 MoCon x    
15 wiki: Prosilica Camera x    
16 SC BCU x    
17 WFS camera x    
18 temperature monitor x    
19 temperature controller     x
20 Interlock x    
21 Shutter (P. Air) x    
22 Water flowmeter x    
23 dichroic mirror motor x    
24 launch beam corrector x    
25 TT aperature wheel x    
26 Pockels cell x    
27 Heater controller x    
28 Laser alignment telescope LAT x    
29 other cameras (?) x    
30 other motors (?)     x
31 Remote fiber switch ARGOS/FLAO   x  


  1. Arbitrator
  2. LALAS
    1. Laser system (LAS)
    2. Launch system (LAN)
  3. LGS wavefront sensor system (LGSW)
  4. Tip Tilt system (TIPTILT)
  5. Control loops
  6. Acquisition and LUCI interface
  7. TCS and AOS info


No. Interface state protocol specification
0 HW devices (commercial) OK OK
1 Services (e.g. LAS, WDHS) OK TwiceAsNice FDR
2 TipTilt Unit done ICE TT spec (Marcel)
3 Instrument TCS draft ICE / AOS FLAO-ARGOS spec (Luca)
4 CCD software interface draft ICE Wfs spec (Gilles)
6 FLAO Interface draft ICE
7 SC BCU configuration pending microgate user manual? (Gilles)
8 SC BCU master diagnostics pending microgate user manual?
9 AdSec BCU configuration pending ICE likely
10 AdSec BCU mirror diagn. pending Arcetri
11 Lucifer scripts pending script


  1. Deployment overview
  2. General installation procedure under Centos 7
  3. Table of ports used by the services and devices
  4. IP addresses at the LBT
  5. wiki: ARGOS Workstations
  6. Argos service supervision and start-up system
  7. Argos Index File
  8. wiki: ARGOS Logging
  9. wiki: Zabbix scratch install
  10. wiki: ARGOS Manuals
  11. List of How-tos
  12. MultiXterm

Development Infrastructure

Repository Name URL
Argos ICS
Argos calibration
AOSupervisor svn+ssh://

  1. ARGOS ICS repsitory has an anonymous user account with read-only permission. The username is anon and password is foo.
  2. MPIA Continuous integration server Jenkins (and the CentOS 7 version) and its setup
  3. LBTO Jenkins
  4. wiki: How to build Docker
  5. 3rd party dependencies
  6. 3rd party tools:
    1. qfits Collection of tools for easy access FITS files.
    2. DS9 FITS image viewer



  1. wiki:Glossary terms
  2. Calibration devices
  3. General installation instructions
  4. Software setup for MPE
  5. Task Automation with Scripts
  6. TwiceAsNice documentation
  7. Code conventions for the ARGOS instrument control software
  8. Mocking Frameworks for C++
  9. FSM code generator comparison
  10. ServiceSupervision
  11. wiki:Python info
  12. Pre-shipment software action items for LAS
  13. Color for read-only line-edit widgets: RGB 233 229 237 (#e9e5ed)
  14. Argos green color: #83c326
Topic revision: r15 - 15 Aug 2018, AndrewColson
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