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NOAO Newsletter - CTIO Operations - September 2000 - Number 63

CTIO Telescope and Instrument Combinations --- the Future

Alistair Walker

CTIO presently operates the Blanco 4-m, the 1.5-m, and the 0.9-m, and has shares in the YALO 1.0-m and the Curtis Schmidt. The SOAR telescope (30% share for NOAO) should begin science operations early in 2003, preceded by Gemini South in 2001B. Other southern-hemisphere facilities soon to come on-line and be available to US investigators are Magellan I (2001) and Magellan II (2003). We note that CTIO will be operating SOAR out of its present budget. Therefore, we need to make radical changes in our Cerro Tololo operations to compensate for the extra responsibilities.

Some three years ago we formulated plans to evolve our instrumentation, particularly on the Blanco 4-m, to complement the new facilities. At the same time, we actively pursued creative ways of running the smaller telescopes, which led to the MACHO agreement on the 0.9-m telescope and the YALO consortium running the 1.0-m in fully queue-scheduled mode. We are now only a few months away from the initial ramp-up of CTIO staff at SOAR. The pressure is not only on the Telops and ETS staff; the scientific staff are stretched thin as well, with participation in US Gemini, SOAR, and various activities newly being undertaken by NOAO as recommended by the AASC report "Astronomy and Astrophysics in the New Millennium."

We are moving rapidly to a model for the Blanco 4-m where we offer a suite of state-of-the-art wide-field instruments, with few or no instrument changes. We no longer make available the f/30 chopping secondary, as its installation (for visitor instruments) involves removing both the Mosaic Imager and the prime focus corrector assembly. The Blanco will continue to be run in classical mode, with astronomers coming to the telescope to observe. Its instruments will complement both SOAR and Gemini, which will have instruments optimized for relatively narrow fields at high resolution.

We will continue to operate the 1.5-m and are considering two low-maintenance operational modes. The first would involve transferring the YALO operation from the 1.0-m to the 1.5-m. This mode, referred to as YALO II, would operate the dual IR-CCD Imager ANDICAM built by Ohio State University in queue-scheduled mode, with Yale and Obs. Lisbon as partners, and with a much greater NOAO share of time (approx 60%) than at the 1.0-m. The partners would pay for two telescope operators who would run the queue. YALO II would start after the present YALO agreement terminates in December 2001. The second operational mode being considered would be to schedule the telescope classically, with two instruments offered in severely blocked mode. Large, long-term programs would be encouraged or mandated; there would be no telescope operator, and Telops assistance would be limited. The instruments under construction are the Cassegrain spectrograph and a CCD imager. In any case, we will retire the Bench-Mounted Echelle (BME) spectrograph at the end of Semester 2000B, ASCAP at the end of 2001B, and IR imaging when ISPI is available on the Blanco.

The smaller telescopes (1.0-m, 0.9-m, and Curtis Schmidt) will be either completely privatized, i.e., operated under shared agreements that require essentially zero CTIO operations load, or closed. The Curtis Schmidt telescope will be last offered to NOAO users for Semester 2001A, with 2001B reserved for Michigan users only as discussed in an accompanying article. We fully realize that some science programs will be difficult or impossible with these changes; hence, we will make every effort to avoid disrupting long-term and survey programs. These types of programs will, if needed, be provided with extra time in the last two semesters of an instrument that is to be retired. Alternatively, we will try to make the transition to another telescope-instrument combination as seamless as possible. We are also very keen to hear from groups who might be interested in operating the smaller telescopes, and we will act as brokers in assembling consortia if need be.

We are sure that the new facilities will create many opportunities. The infrared imager ISPI will mount at an f/8 sideport on the Blanco, delivering a 10 x 10 arcmin field and 0.3 arcsec pixels with a 2K HgCdTe array, while the IFU (Integral Field Unit) feed to the Hydra Bench Spectrograph will provide a finely sampled focal plane to the virtual slit of the bench-mounted spectrograph, which can be configured to simulate many of the present capabilities of the RC and Echelle spectrographs. We will continue to operate Hydra and Mosaic for at least another five years. A mid-life upgrade of CCDs and controllers for Mosaic that permits much faster read time is a possibility, as is moving to a 16K array with new corrector. The latter is an expensive proposition, and one we would not contemplate if an 8-m class wide-field telescope were to be built on Cerro Pachón. Such a telescope is recommended in the Decadal Survey Report.

Two instruments under study by the NOAO­Tucson instrumentation group are of future interestNGOS and NEWFIRM. NGOS (Next Generation Optical Spectrograph) is a high-efficiency beam-fed multi-object spectrograph, which could replace Hydra. NEWFIRM is a 4K IR imager. It is likely that one or both of these instruments would be shared with KPNO or other partners.

For SOAR, there is strong interest in adaptive optics within the partner community; CTIO has an instrumentation development wedge opening for this project in 2001 and is in the process of forming a project team. Gemini South and SOAR would then be the only US-accessible facilities with AO in the Southern Hemisphere. Another desirable instrument in the SOAR initial instrument complement is an IR multi-object spectrograph; discussions on how best to procure such an instrument are underway. An interim spectrograph will either be an upgrade of CTIO-IRS or OSIRIS. The latter could also provide an IR imaging capability close to first light, which might otherwise be lacking.

Gemini, of course, has an active instrumentation program for the Gemini South telescope. In addition to the instruments in the accompanying table, Gemini plans to install NICI (Near-IR Corono-graphic Imager) in 2004 and a Multi-Conjugate Adaptive Optics (MCAO) system in 2004­2005. Their program is presently under review and likely to change. For instance, Gemini now proposes to go straight to MCAO on Gemini South rather than Hokupa'a South as an interim AO facility. Consequently, the instrument complement for Gemini South is being reevaluated.

CTIO will continue to have a strong instrumentation program, both to support present instruments and to provide future instruments. We hope to be able to expand the program so that we can participate in providing instrumentation for the US 6­10 m telescopes. Instruments may also be procured by partnerships with universities or built by NOAO­Tucson.

The accompanying table depicts our instrumentation plan for the CTIO telescopes through 2003. For reference, we also include the Gemini South instrumentation plan. Details will almost certainly change, and we are interested in specific suggestions. The Blanco instruments mentioned that may be unfamiliar to most readers are IFU and ISPI. IFU is an Integral Field Unit feed that is permanently mounted to the Hydra bench spectrograph. First engineering tests are scheduled for November 2000; project manager is Tom Ingerson. ISPI is a 2K all-transmission IR imager with 2K HgCdTe array, mounted permanently at the f/8 RC focus to give a 10 x 10 arcmin field with 0.3 arcsec pixels; project manager is Ron Probst. See the CTIO Web site at for updated information.

CTIO, SOAR, and Gemini South Instrumentation 2000-2003

Telescope       2000B   2001A   2001B   2002A   2002B   2003A   2003B     Comments
Gemini South
 T-ReCS                           x       x       x       x       x       Deliver Q2 2001
 Phoenix                          x       x       x       x       x       Share with SOAR
 HROS                                                     x?      x?      Deliver Q3 2002?
 GMOS                                             x       x       x       Deliver Q4 2001
 Flamingos I                      x(Jun-Nov)      x               x       Share with KPNO
 GNIRS                                                    x       x       Deliver Q3 2002
 Flamingos II                                                     ?
 Abu              x       x                                               Commissioning only

 Optical Imager                                   x:      x       x       Commissioning instrument
 IR Imager                                                x?      x?      Not yet funded
 Goodman Sp.                                      x:      x:      x
 IFU Sp.                                          x:      x:      x
 CTIO IRS                                                 x:      x       Or Osiris
 Phoenix                                                  x:      x       Share with Gemini

 Mosaic II        x       x       x       x       x       x       x       These four instruments
 Hydra            x       x       x       x       x       x       x        can all be mounted
 ISPI                                     x       x       x       x        simultaneously.
 IFU                              x       x       x       x       x       
 RC Spec          x       x       x:      x:      x:                      Replaced by GMOS, Goodman Sp., IFU
 Echelle          x       x       x:                                      Replaced by IFU, HROS(?)
 IRS              x:      x:      x:                                      One of these two instruments
 Osiris           x       x       x       ?       ?                        will likely go to SOAR
 VISITOR                                                                  Only in campaign mode?

 CFCCD            x       x       x       x                               Retire or severely blocked
 CSCCD            x       x       x       x                               Retire if no Andicam option
 Osiris/Cirim     x       x       x       ?                               Retire
 ASCAP            x       x       x                                       Retire
 BME              x                                                       Retire
 Andicam                                          x?      x       x       Dual IR and CCD imager

 Andicam          x       x       x                                       Present YALO agreement 
                                                                          ends after 2001B.

 CFCCD            x       x       x       ?                               Close or operate with partners.

 NFCCD            x       x                                               Close after 2001A.

   x: designates restricted scheduling.

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