Telescope and Site Group Status

1
Telescope and Site Group Status

• V. Krabbendam
• C. Claver

2
LSST Project Management
LSST Director Anthony Tyson
Science Advisory Board Zeljko Ivezic, Philip Pinto
Science Assurance System Scientist Christopher
Stubbs
Project Manager Donald Sweeney
System Engineering Jacques Sebag (acting)
Project Coordinator Suzanne Jacoby
Construction Proposal Larry Daggart
Camera Steve Kahn, Sci. Bill Althouse, Mgr.
Telescope/Site Charles Claver, Sci. Victor
Krabbendam, Mgr.
Data Management Tim Axelrod, Sci. Jeff Kantor,
Mgr.
3
Telescope and Site Organization
Telescope/Site Charles Claver, Sci. Victor
Krabbendam, Mgr.
Administrator Melissa Bowersock
Project Engineering Larry Daggert
System Engineer Jacques Sebag
Opto/Mech Engineering Doug Neill
Facilities, Site Dome Jeff Barr
Software Control German Schumacher
Electrical Engineering Mike Warner
Design Rich Gomez
Optical Engineering Ming Liang
4
Scope Objective

• Design, Build, and Commission LSST Telescope and
  Local Facilities
• Telescope Optics, Mount, TCS, Coating Plant,
  Alignment, and Utility Systems
• Mountain Top Site, Telescope Facility, Dome,
  Support Building and Utility Systems
• Local Infrastructure Off Mountain Office/Data
  Facility

5
Scope Continued

• Support LSST Project Development
• Science Definition, Requirements, Interfaces,
  Operations Plan
• OCS Development
• Conduit NOAO In-Kind Contribution
• , Offices, Resources etc.

6
Near Term Program Plan

• Conclude Site Selection Process
• Conclude Optical Design Definition
• Start M1 Contract Monitoring Effort
• Expand Concept Development
• Alignment Reconstructor, Sensitivity, Scattered
  light etc
• Telescope Structure Study
• Architectural Advance of Building and Dome
• Baseline Mirror Concepts (M2 M3)
• Prepare For D D Funding

7
Site Selection

• Down Selection Report Done, Formal Contact
  Established
• Cerro Pachon,
• Las Campanas,
• San Pedro Martir, (site visit in September)
• La Palma (site visit in August)
• Study to Evaluate Satellite Data Issues
• Correlating Local Data to Global Weather Patterns
  
• Final Site (2) Selection Meeting 9 October 2004

8
Optical Design Tiger Team
FOV Design 3.0 deg. 3.5 deg. 4.0 deg.
Ming (short) 253 (0.65) 345 (0.64) 450 (0.64)
Seppala (short) 230 (0.55) 302 (0.52) 393 (0.50)
Seppala (long) 265 (0.61) 301 (0.53) 366 (0.45)

• Objective Chose Design By October 2004
• Evaluating 9 (10?) Point Designs
• Dozens of Characteristics Tabulated for
  Comparison
• Initial Evaluation Scheduled for July 04

Constant Illumination
Low Asphericity
9
Primary Mirror Contract

• Contract in Final Stages of Review
• Raw Materials and Engineering
• Casting
• Optical Figuring
• Cell Integration and Testing
• LSST Board Established 4 Person Review and
  Approval Subset

4 Phase Effort
10
Optical Reconstructor

• Regis Tessieres Completed 6 month Development
  Study
• Derive basis functions for field dependant
  aberrations for mirror bending and body motions.
• Reconstructor model for bending modes
• Reconstructor model for rigid body modes
• Monte Carlo simulation of initial alignment and
  tolerances
• Monte Carlo simulation of operational alignment

11
Principle of the method
12
Alignment Simulator
Hi
C(Hi) Noise
C(Hi) Noise
- Cbending(Hi)
Bending modes
Body motions
Corrections Noise
13
Optical Reconstructor
14
Short ConfigurationOptical Sensitivity

• Little difference in body motion sensitivity for
  basic configutation.
• M1M3 monolith results in higher sensitivity

15
Short Configuration Stray Light
Note absence of specular stray light path

• Mirror reflectivity 100
• Ghosting properties Lens reflectivity 1 per
  surface, CCD surface reflectivity 15
• Scatter properties
• Mirrors 18A rms micro-roughness Level 600
  particulate contamination
• Lenses 20A rms micro-roughness Level 300
  particulate contamination

16
Short Configuration Stray Light
17
Telescope Structure

• Initial Warren Davidson Study Complete
• Long Tube
• Stiff Structure, f(n1)10hz
• Relatively Light , 200T
• Further In-house Design in Progress
• Preparing for Second Study
• Short Tube
• Open Structure
• Industrial Source

18
ADC Investigation

• Need / Dont Need
• Science Requirements Document Immanent
• Feasibility? - Ming Implementation of Willstrop
  Design in Progress
• Refraction Study with Patrick Wallace
• Capture Specific Impact to LSST Concept
• Quantify Telescope Req. vs. Astrometric and Image
  Performance (e.g. to guide or not to guide)
• Ready to Support Evaluation Committee

19
ADC Investigation
R Band at 40 ZD and 70 ZD
20
Architecture Work Initiated

• Preliminary Requirements Document Complete
  (distribution very soon)
• First Order Building Definition
• Space Requirements
• Initiating Layout Work, Building and Dome
• Several Concepts Will Be Flushed out
• Objective Community Discussion, Identify
  Challenges, Provide Focus for DD Effort

21
Other On-Going Work

• Wavefront Sensor Concept Development
• LLNL Coating Evaluation Continues
• M2 Fabrication Study In Progress
• UofA Effort
• Evaluate Profilometer and Study Interferometric
  Approaches
• Supporting OCS Development

22
Summary

• T S Project Team Solidifying
• Project Team Meeting in Early August
• Preparing For D D Funding
• Focus on Maturing Requirements and Concept