(Radio) Astronomical Instruments. How are they work, how they are planned, designed, built, tested and maintained. Carlos A. Durán MPIfR, Bonn, 22 nd of January 2018
Program Receiver Technology used in (Radio) Astronomy Instruments & Telescope Drivers Instruments & T elescope Drivers Front-end Scientific Interest Heterodynes (single pixel and arrays) Technology Calorimeters / Bolometers Interface and Specification. Backend Project Management Spectrometers: AOS / FFTs Correlator (Auto and Cross) ADC and Total power detectors. Constraints, limitations and barriers Constraints, limitations and barriers The need of low temperature: Cryostat and Technology & technics Cryogenics Atmosphere Money (Quasi) Optics, Telescope Coupling and interfacing. Logistics & Operation Competitors / use. The design of an instrument. Telescopes and configurations Modeling and simulations Single Dish / Arrays Selection of Components Ground-base / Air- Balloon born / Space Optics Design (Mirrors, filters, windows) Mechanical design Testing, Commissioning and Acceptance. Electronics and Electrical Interfacing Software Operation: The non-visible backstage. Tune up, characterization and commissioning Data Handling, Calibration and Archiving Lab Tests and Operation points Surface accuracy and efficiencies Merit figures: Allan Variance, T Rec , Thermo/mech. Pointing and Atmospheric models Stabilities. Uncertainties Power Commissioning. Cryogenics
(Radio)Astronomy Instruments Collecting Area Telescope + Detectors + Signal conditioners Signal processors Refrigerators Instruments Vacuum vessels Optics SW/Control Modules
Instruments & Telescope Drivers What if What if…? ? We explain / study this process / phenomenon / condition ? Scientific Inter Scientific Interest est Fundamental Question
Instruments & Telescope Drivers We explain / study this process / phenomenon / condition ? Fundamental Question • Cosmology • Spectroscopy • Dynamics • Gravitational waves • Other Astro. Phenomena.
Instruments & Telescope Drivers Scientific Inter Scientific Interest est Update / New generation For that we build that kind of Telescope Technology echnology
Instruments & Telescope Drivers Telescope equipped with this kind of instrumentation Update Technology echnology New generation Performance Has to fulfill this and that condition, and to be built in this and that way Interface and Specification Interface and Specification
Instruments & Telescope Drivers Interface and Specs. Interface and Specs. And all will be built by these institutions, in this time, budget, following these milestones and standards Pr Project Management oject Management
Instruments & Telescope Drivers Interface and Spec. Interface and Spec. Documents Documents • Design & Construction (Telescope specifications) Control, SW, Optics, dynamics, stability, Metrology (Tiltmeters, linear sensors), deformations, etc. • Instruments Scope (Scientific target) Interface (SW, Optics, Electronics, Electrical, Cooling, weight, volume, safety, etc.) • Delivery / Deliverables (Parts, schematics, drawings, recommendations, etc)
Instruments & Telescope Drivers Interface and Spec. Documents Interface and Spec. Documents • Test, Commissioning and Acceptance • Criticality assessment Maintenance and Lifespans Failure Action plans & Spares • Auxiliary system definitions Power, network, radiometer, Pointing devices, signal and time refs, Calunit, HVAC, others • Facilities (definitions)
Instruments & Telescope Drivers Pr Project Management oject Management (Design & Construction) Tools. PM Control and tracking (SW Tools) Budget control Meetings Minute meetings Agreements
Constraints, limitations and challenges Technology + Specs echnology + Specs Type of Telescope à Size Resolution / Location à Size Optical Configuration à Size Type of instrumentation (BB_02)
Constraints, limitations and challenges Atmospher Atmosphere e à “Site” “Site” • Atmospheric windows
Constraints, limitations and challenges Atmospher Atmosphere e à “Site” “Site” • The higher/dryer/more stable, the better à Site testing
Constraints, limitations and challenges Resour Resource$ ce$ • Type • Size • Configuration • Site (Ground/Balloon/Airborne/Space) • Instrumentation Instrumentation • Support & Auxiliary systems • Manpower • Operation
Constraints, limitations and challenges Logistics and Operation Logistics and Operation • How (mode) 24x7 / Partial / seasonal In situ / Service mode / Remote / Robotic • For How long / Conditions Life span (Politics / scientific / technology / $ / Manpower) • Where Access / Serviceability • Criticality assessment Failure Action plans & Spares
Constraints, limitations and challenges Competitors v/s demand Competitors v/s demand • Keep the system running and attractive State-of-the-art instruments Reliable, shinny and QA • Scientific throughput Papers / Euro Hours on Sky / year Discoveries (relevance) • Using chances (for instrument construction)
Telescopes and Configurations E.M. wave Polarization (Electric Field Direction)
Telescopes and Configurations Free space E.M. wave propagation
Telescopes and Configurations Radiation Pattern (P n )
Telescopes and Configurations Radiation Pattern HPBW: Half power beam width
Telescopes and Configurations Antenna Parameters 2 π π P ( , ) sin( ) d d P ( , ) d Ω = ∫ ∫ θ φ ⋅ θ θ φ = ∫∫ θ φ Ω Beam area A n n 0 0 (pattern solid angle) 4 π P ( , ) d Ω = ∫∫ θ φ Ω M n Main beam area Main beam P ( , ) d Ω = ∫∫ θ φ Ω Minor lobes area m n min or lobes Ω = Ω + Ω A M m Ω M Main beam efficiency ε = M Ω A
Telescopes and Configurations Directivity: Effective Aperture Aperture efficiency Gain: Eff. factor Blockage à SR, Legs Spillover à Illumination
Telescopes and Configurations • Types: “Wire” Antennas / Aperture | Single Dish / Arrays • Optical configuration (Apertures). – Parabolic On Axis / Off Axis – Nasmyth, Cassegrain, Gregorian Site (Location) Ground / Airborne / Balloon / Space •
Telescopes and Configurations Types: “Wire” Antennas / Aperture
Telescopes and Configurations Types: Aperture
Telescopes and Configurations Typical Optical configuration ypical Optical configuration (Reflector). Parabolic, On Axis / Off Axis Cassegrain, Gregorian Nasmyth (Coude)
Telescopes and Configurations Types: Aperture - Reflector Big collecting area, focusing radiation into a focal point (waist)
Telescopes and Configurations *Optical configuration *Optical configuration (no blockage) (no blockage) Cross-Dragone à CCAT-p
Telescopes and Configurations Arrays (Apertur Arrays (Apertures) es) Large Aperture “Damaged” large aperture
Telescopes and Configurations Arrays (Apertur Arrays (Apertures) es)
Telescopes and Configurations Arrays (W Arrays (Wir ires or Apertur es or Apertures) es)
Telescopes and Configurations Site (Location) Able to Observing Failure Tracking/ Site Atmosphere Access DataRate Limitations Cost C/O update Run correction control Groudbase Thin (altitude) HW/SW always 24/7 at will High anytime No OK $$/$ Airborne Very thin HW/SW daily 10hrs (rtb) High Daily or rtb Power/weight OK $$$/$$ monthly (after Balloon Vert thin HW/SW monthly months (rtb) Mid Power/Weight Airstreams $/$ mission) years with Satellite/Space non-existing SW no Low No Power/Weight OK $$$$/$ fxied date
Telescopes and Configurations Ground Based: APEX (2 Nasmyth + 1 cassegrain)
Telescopes and Configurations APEX Diameter 12 m Mass 125000 kg 264 aluminium panels Main reflector average panel surface r.m.s. 5 micron Hyperboloidal Aluminium Secondary reflector Diameter 0.75m Mounting Alt-Az Surface accuracy 17 micron (r.m.s.) Pointing accuracy 2" rms over sky (r.m.s.) Pointing accuracy on track 0.6" Manufacturer Vertex Antennentechnik f/D 8 Beam width (FWHM) 7.8" * (800 / f [GHz]) Receiver cabins 2 Nasmyth (A,B) + 1 Cassegrain (C) 24 . 4 / η a Jy / K forward efficiency (ηf), aperture efficiency (ηa), main beam efficiency (ηmb), and Moon efficiency (ηM).
Telescopes and Configurations Balloon: STO2 (South Pole) Arrays at 1.4 and 1.9 THz
Telescopes and Configurations Space : Herschel HiFi + PACS + SPIRE
Telescopes and Configurations Space : Herschel
Telescopes and Configurations Boing 747SP 2.7m
Testing, commissioning and acceptance • Positioning, tracking, pointing, accelerations, Metrology, Mass balance (requires of some instrumentation) • “Antenna” Parameters Main Dish / Secondary (+Tertiary) Gain Efficiencies Frequency limits (optics parameters) Throw (Woobler) / Focus (Subreflector)
Testing, commissioning and acceptance Positioning & Tracking
Testing, commissioning and acceptance Beam, efficiencies, spillover: Determination by de-convolving planet scans Telescope beam (*) planet = scan (apparent beam)
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