Large Synoptic Survey Telescope: the - construction of a discovery machine Dr Angelo Fausti () (AURA/LSST) - DocuShare
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Large Synoptic Survey Telescope: the construction of a discovery machine Dr Angelo Fausti (afausti@lsst.org) (AURA/LSST) UFRGS - Sep 2019
9th Project and Community Workshop (Tucson) Aug 12-16
Outline
● Introduction
● Highlights of the LSST construction
○ Primary/Tertiary mirror (M1M3)
○ LSST Camera
○ Telescope & Site
○ Data Management
● Testing LSST Science Requirements
● The Engineering Facility database (EFD)
● The LSST Science Platform
● Final remarks
From dream to reality
● Initial ideas: The Dark Matter Telescope (1998)
● LSST design and development proposal in (2003)
● Mirror construction started (2008)
● Top-ranked in the decadal survey (2010)
● Construction started (2014)
● Early integration/commissioning activities (2018-2021)
● Operations start in 2022 to conduct a 10-years survey
US$ 30M US$ 473M US$ 168M
+ operations funds = US$ 1B project!
The mission of LSST is to build a facility that will produce a vast
astronomical dataset for unprecedented discovery of the deep and
dynamic Universe.
+ +
Huge facility Fast telescope 8.4m mirror
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3.2Gpixel Camera Petascale facility ~ 1M lines of code
A very compact optical design f/1.2 Primary/Tertiary mirror (M1/M3)
Primary/Tertiary mirror (M1M3) preparing for glass melt (Tucson) March 2008
~5 years grinding and polishing final optical surface
M1M3 completion (Tucson) April 2015
Oversized ~ 9 m Overloaded ~40 ton
M1M3 mirror cell and its 156 actuators (active optics)
16.8-ton M1M3 lifted with 54 vacuum pads (but only 4 four times during the whole experiment)
M1M3 on its way to the summit May 2019
Coating chamber final acceptance (Germany) June 2018
Coating chamber arrived to the summit November 2018 M1M3 will need to be washed and recoated every two years, and the Secondary Mirror (M2) every five years, during the 10-year survey.
M2 coating completed July 2019
LSSTCam, wide field-of-view 3.5 deg ~ 7 full Moons
Property LSSTCam DECam
# of pixels 3200M 570M
# of detectors 189 62
Pixel Scale 0.2 0.2637
(arcsec/pixel)
Readout (s) 2 20
Dynamical range (bits) 18 16
Image size 6.4 1
uncompressed (GB)LSST Camera - sensor’s production completed Feb 2019
Raft assembly completed (SLAC)
July 2019
E2v sensor contamination example
All sensors delivered and all rafts completedScience rafts insertion has started Aug 2019 Focal plane grid
Filter exchange system u,g,r,i,z,y
Filter exchange system being tested (France) September 2019
Low Earth Orbit (LEO) satellites, a real threat. Trail near saturation induces three orders of crosstalk on LSST sensor`.
Starlink++ and LSST https://www.lsst.org/content/lsst-statement-regarding-increased-deployment-satelli te-constellations# SpaceX plan is to deploy 4820 new LEO Satellites by 2027
Dome slowly progressing….
June 2019Telescope Mount Assembly (TMA) - Spain Arriving in Chile this week
A 350-ton discovery machine The telescope has to move really fast (cross the sky in about 18s). It has to stop and settle in 4s, take a 2 x 16s exposures, and move again to the next position. Repeat that ~1000 times every night, for 10-years.
LSST Survey Strategy (simulation) Main survey area: 18000 sq deg, ~800 visits per pointing
Data transfer: 80 Gb/s (sustained) between the Base Site to LSST Data Facility (Urbana) November 2018
Data Products Prompt Processing ● Collect, transfer and archive 15TB images/night ● Process every visit, image difference, generate alerts on transients and changes in 60s ● 1-10M real-time alerts/night (no proprietary period) Annual Data Release (2-yr proprietary period) ● LSSTCam SV data release scheduled end of 2022 ● DR1 end of 2023 (catalog 18 billion objects, 350 billion sources) ● DR11 in 2034 (catalog 37 billion objects, 7 trillion sources)
The LSST Science Pipelines https://pipelines.lsst.io
Developer Guide https://developer.lsst.io
50+ DM developers
Continuous Integration (nightly releases)
https://ci.lsst.codes
- Verify Alert Processing
- Verify Data Release ProcessingTesting Science Requirements on precursor datasets
https://ls.st/lpm-17
Astrometry performance on HSC (AM1)
Distribution of the RMS in the measured position of the sources for the same object across visits.Tracking Science Pipeline metrics SQuaSH
Telemetry Auxilary Telescope Camera (Tucson lab) Engineering Facility Database
The LSST Science Platform https://ls.st/lse-319/
The LSST Science Platform https://ls.st/lse-319/ ● LSST software stack ready-to-use, no need to install anything ● No need to download LSST data ● Use storage and computing resources available at the Data Access Center (or Google/Amazon cloud) ● The notebook environment is the “new terminal” ● Combines code, narrative and visualization ● Excellent for exploratory/interactive data analysis ● See LSST stack club on github
Gaia DR2: making a density map for 1.7B objects Distributed computing from the notebook using Dask
Final remarks ● Technical progress and performance is excellent ● LSST continues to encounter technical challenges ○ Early integration and commissioning activities ● Challenges and Risks ○ Now 3.5 months schedule contingency to planned start of the survey ○ Telescope Mount (Dome) now on the critical path – camera is close ○ Staffing challenges / Departures / Transitions ● New data rights model being discussed ● Transition to operations already started (pre-operations, NCOA)
Questions?
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