# Presentation: 111087

## CTIO and the Dark Energy Camera

- Prepared for the CD-1 Director’s Review
- Tuesday, July 25, 2006Fermilab
- Alistair R. Walker

## Topics for this talk

- Announcement of Opportunity.
- DES proposal and review.
- Review recommendations.
- The CTIO site and the Blanco telescope.
- Blanco Telescope Improvements.
- CTIO staff involvement.
- DECam and the community.

- Prepared by ARW

- CD-1 Director's review - Fermilab

## Announcement of Opportunity

- To develop, in partnership with NOAO, a major new instrument for the Blanco 4m telescope at CTIO.
- Suggested that such an instrument exploit the wide-field capabilities of the telescope.
- This would be a facility instrument - useable by the community, available ~2008.
- Up to 30% of the time would be made available for 5 yrs.
- NOAO would contribute telescope operations, some telescope upgrades, and partner in Data Management.
- Letters of intent due by March 15 2004; Proposals due by August 15 2004.
- A proposal from the Dark Energy Survey Collaboration was received on July 15, 2004.

- Prepared by ARW

- CD-1 Director's review - Fermilab

## Proposal & Review

- The Dark Energy Survey Consortium proposed to build a very large prime-focus CCD imager, and with it carry out a galaxy survey in the South Galactic Cap, to improve our knowledge of Dark Energy.
- External Review by the BIRP = Blanco Instrumentation Review Panel
- Were impressed by the thorough scientific and technical description of the project.
- Thought the instrument would be an asset to the national observing system, and the survey archive would enable an enormous amount of science.

- Prepared by ARW

- CD-1 Director's review - Fermilab

## BIRP recommendations

- They recommended to proceed with the partnership, provided that:
- The camera, the data reduction pipelines and the DES data archive be deliverables.
- There be an external oversight committee.
- DECam should not preclude use of the F/8 focus.
- Filter complement changes be possible as part of normal operations.
- NOAO should supplement the consortium *griz* filters.
- An E/PO plan be integrated into the project.
- NOAO commit adequate resources to enable community science.
- A formal set of written acceptance testing plans and performance metrics be developed.

- Prepared by ARW

- CD-1 Director's review - Fermilab

## The CTIO Site

- CTIO is a division of NOAO, operates the Blanco and SOAR 4-m telescopes, and is part of the SMARTS small telescope consortium.
- AURA manages NOAO under a cooperative agreement with the NSF.  The legal entity in Chile is AURA.
- NOAO in Chile employs 86 people, participating in all NOAO programs.
- CTIO has Scientific staff, an Engineering group, and a Telescope operations group.
- The La Serena campus is shared with Gemini, SOAR, and soon, LSST.
- Users - a very diverse and creative community.  Chile - 10% time.
- Operations are carried out with full regard of Chilean and US (OSHA) standards and guidelines.

*The NSF Senior Review can potentially affect CTIO’s ability to participate in this project.*

- Prepared by ARW

- CD-1 Director's review - Fermilab

## Slide 7

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- CD-1 Director's review - Fermilab

## Slide 8

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- CD-1 Director's review - Fermilab

## The Blanco Telescope

- Commissioned in 1974, largest telescope in the Southern Hemisphere until 1998, primary mirror quality (D80 = 0.25 arcsec) defined state-of-the-art.
- Prime focus CCD imagers leaders in AΩ. *The critical observations for the discovery of Dark Energy were made with this telescope.*
- Extensive set of improvements in the 90’s, led by Jack Baldwin.
- Primary mirror active support system (active optics), to replace the passive support system.
- Environmental improvements, e.g. windows in the dome to promote air flow, removal of heat sources.

**THE SITE:**
-   October to January - weather improving, nights get shorter (av. 6.8 hr/night useable)
-   Mean site seeing at 5m above ground = 0.65 arcsec

- Prepared by ARW

- CD-1 Director's review - Fermilab

## Blanco telescope - recent progress

- Primary mirror repositioned 2.3mm in z-direction
- Radial support mechanism understood
- Mirror movement in cell identified and (partially) resolved
- Telescope flexure measured
- Aluminization chamber upgrade underway
- Two degree slew time reduction from 35s to 17s - feasibility established

-                       
- Image Quality obtained by the SuperMacho program, 2005B, airmass corrected, VR filter.  Dates: 2005-09-05 to 2005-12-31, Blue: pre-shutdown, red: post-shutdown, approx equal number (~580) exposures each.

- Prepared by ARW

- CD-1 Director's review - Fermilab

## Blanco Telescope - still to come

- Telescope
- Fully replace the primary mirror edge supports.
- Upgrade Telescope Control System (TCS).
- Evaluate telescope Environmental Control System (ECS).
- Infrastructure - Integration issues
- Clean room
- Utilities including glycol, He lines
*	**These activities will be undertaken by the CTIO Engineering & Technical Services and Telescope Operations Groups *
*	**IMPORTANT NOTE:** **DECam will itself address issues such as maintaining collimation, optical corrector performance, prime focus cage thermal environment.  Active focus control, on-instrument alignment sensor.*

- Prepared by ARW

- CD-1 Director's review - Fermilab

## CTIO DECam Involvement

- Alistair Walker - CTIO Director
- Tim Abbott -  Blanco Telescope Scientist, DECam Deputy P.M.
- Chris Smith - Dep. Head of NOAO Data Products Program (DPP)
- Chris Miller - DPP scientist
- Ricardo Schmidt, Peter Moore - EE’s:  CCDs and controllers
- Also -  Abi Saha & Todd Boroson from NOAO Tucson; The Tucson Monsoon controller group.
-  Functions -
- Participate in project activities - management & technical meetings and discussions.
- Develop specifications, plans in partnership with other collaboration members. (example - use of LabView)
- Work on specific technical tasks, e.g. CCDs, controllers.

- Prepared by ARW

- CD-1 Director's review - Fermilab

## NOAO User Community use of DECam

- The User community has two routes to DECam data:
- The DES itself.  A project deliverable is that the DES data flows into the NOAO Science Archive (NSA).  The NSA will also host reduced data and survey products.  NOAO & NCSA are collaborating on developing the NSA, NCSA will provide some of the services for its operation.  Access is by a VO-compliant portal.
- Through observing with DECam on individual projects, via the usual NOAO observing proposal mechanism, whereby time is assigned by competitive review.   See http://www.noao.edu/gateway/propinfo.html  Some of these projects could be surveys themselves.  This requires a pipeline that processes non-DES data, and also flows it into the NSA.

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- CD-1 Director's review - Fermilab

## NOAO User Community use of DECam

- Document - *Community Needs for the Dark Energy Camera & Data Management System:*
- 	*The DES requirements are in general very stringent, and there is a high degree of overlap between DES and community requirements.  *
- Highlights -
- DECam should be useable over all optical wavelengths 320-1100 nm (an Atmospheric Dispersion Corrector is not a requirement).
- Filter mechanism design should both minimize filter swaps, and allow such swaps to be carried out safely in a reasonable time.
- F/8 mirror easily available (flip top end).
- Observing protocols and operation modes are listed.
- Data format and metadata requirements specified.
- DMS must support use both by DES and the community.

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- CD-1 Director's review - Fermilab

## The End

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## Slide 16

- Prepared by ARW

- CD-1 Director's review - Fermilab