The Carnegie Observatories in 2019 celebrated 50 years since Las Campanas in northern Chile was chartered as the site for its large telescopes. Since that time Carnegie has deployed four telescopes, the Swope 1 meter, the du Pont 2.5 meter and, on behalf of the Magellan consortium, the two Magellan 6.5 meter. All telescopes are routinely used producing world class science. In this paper we will review the current science operations that are mainly performed in a classical observing mode, and then present the future strategies needed across the observatory to operate in survey, remote and robotic mode.
Las Campanas Observatory (LCO) of the Carnegie Institution of Science has been operating in Chile for about 50 years, currently operating four main telescopes. Carnegie operates the two 6.5 meter Magellan telescopes on behalf of a partnership that includes a consortium of universities. The Magellan Telescopes were commissioned in 2000 and 2002 and offer the consortium users a suite of twelve instruments. In this paper we will first provide a brief description of the science, technical and administrative structure of the observatory. We will then present an updated review of the Magellan telescopes operations and maintenance. Details on status and performances of the instruments will be given. We will finally cover the operations of the duPont 2.5 meter and Swope 1 meter telescopes including the current and future collaboration with the two hemisphere surveys SDSS-IV and SDSS-V.
The Magellan Telescopes are a set of twin 6.5 meter ground based optical/near-IR telescopes operated by the Carnegie Institution for Science at the Las Campanas Observatory (LCO) in Chile. The primary mirrors are f/1.25 paraboloids made of borosilicate glass and a honeycomb structure. The secondary mirror provides both f/11 and f/5 focal lengths with two Nasmyth, three auxiliary, and a Cassegrain port on the optical support structure (OSS). The telescopes have been in operation since 2000 and have experienced several small earthquakes with no damage. Measurement of in situ response of the telescopes to seismic events showed significant dynamic amplification, however, the response of the telescopes to a survival level earthquake, including component level forces, displacements, accelerations, and stresses were unknown. The telescopes are supported with hydrostatic bearings that can lift up under high seismic loading, thus causing a nonlinear response. For this reason, the typical response spectrum analysis performed to analyze a survival level seismic earthquake is not sufficient in determining the true response of the structure. Therefore, a nonlinear transient finite element analysis (FEA) of the telescope structure was performed to assess high risk areas and develop acceleration responses for future instrument design. Several configurations were considered combining different installed components and altitude pointing directions. A description of the models, methodology, and results are presented.
Cerro Las Campanas located at Las Campanas Observatory in Chile has been selected as the site for the Giant Magellan
Telescope. We report results obtained since the commencement, in 2005, of a systematic site testing survey of potential
GMT sites at LCO. Seeing data have been obtained at three potential sites, and are compared with identical data taken at
the site of the twin Magellan 6.5m telescopes. In addition, measurements of the turbulence profile of the free-atmosphere
have been collected. Co. Las Camapanas and the Magellan site are nearly identical in their seeing statistics, and
apparently their average ground-layer characteristics.
Cerro Las Campanas located at Las Campanas Observatory (LCO) in Chile has been selected as the site for the Giant
Magellan Telescope. We report results obtained since the commencement, in 2005, of a systematic site testing survey of
potential GMT sites at LCO. Atmospheric precipitable water vapor (PWV) adversely impacts mid-IR astronomy
through reduced transparency and increased background. Prior to the GMT site testing effort, little was known regarding
the PWV characteristics at LCO and therefore, a multi-pronged approach was used to ensure the determination of the
fraction of the time suitable for mid-IR observations. High time resolution monitoring was achieved with an Infrared
Radiometer for Millimeter Astronomy (IRMA) from the University of Lethbridge deployed at LCO since September of
2007. Absolute calibrations via the robust Brault method (described in Thomas-Osip et al.1) are provided by the
Magellan Inamori Kyocera Echelle (MIKE), mounted on the Clay 6.5-m telescope on a timescale of several per month.
We find that conditions suitable for mid-IR astronomy (PWV < 1.5 mm) are concentrated in the southern winter and
spring months. Nearly 40% of clear time during these seasons have PWV < 1.5mm. Approximately 10% of these nights
meet our PWV requirement for the entire night.
Cerro Las Campanas located at Las Campanas Observatory (LCO) in Chile has been selected as the site for the Giant
Magellan Telescope. We report results obtained since the commencement, in 2005, of a systematic site testing survey of
potential GMT sites at LCO. Meteorological (cloud cover, temperature, pressure, wind, and humidity) and DIMM
seeing data have been obtained at three potential sites, and are compared with identical data taken at the site of the twin
Magellan 6.5m telescopes. In addition, measurements of the turbulence profile of the free-atmosphere above LCO have
been collected with a MASS/DIMM. Furthermore, we consider photometric quality, light pollution, and precipitable
water vapor (PWV). LCO, and Co. Las Campanas in particular, have dark skies, little or no risk of future light pollution,
excellent seeing, moderate winds, PWV adequate for mid-IR astronomy during a reasonable fraction of the nights, and a
high fraction of clear nights overall. Finally, Co. Las Campanas meets or exceeds all the defined science requirements.
The twin 6.5m Magellan Telescopes have been in routine operations at the Las Campanas Observatory in the Chilean
Andes since 2001 and 2002 respectively. The telescopes are owned and operated by Carnegie for the benefit of the
Magellan consortium members (Carnegie Institution of Washington, Harvard University, the University of Arizona,
Massachusetts Institute of Technology, and the University of Michigan). This paper provides an up to date review of the
scientific, technical, and administrative structure of the 'Magellan Model' for observatory operations. With a modest
operations budget and a reasonably small staff, the observatory is operated in the "classical" mode, wherein the visiting
observer is a key member of the operations team. Under this model, all instrumentation is supplied entirely by the
consortium members and the various instrument teams continue to play a critical support role beyond initial deployment
and commissioning activities. Here, we present a critical analysis of the Magellan operations model and suggest lessons
learned and changes implemented as we continue to evolve an organizational structure that can efficiently deliver a high
scientific return for the investment of the partners.
Las Campanas Observatory has been designated as the location for the Giant Magellan Telescope (GMT).
We report results obtained since the commencement, in 2005, of a systematic site testing campaign at LCO.
Meteorological (cloud cover, temperature, pressure, wind, and humidity) and DIMM seeing data have been
obtained at three potential sites, and are compared with identical data taken at the site of the twin Magellan
6.5m telescopes. In addition, measurements of the turbulence profile of the free-atmosphere above LCO have
been collected with a MASS/DIMM. We examine the contribution to the seeing arising from turbulence in the
ground layer (defined here as below an altitude of 500 m) through the difference between the turbulence integrals
in the full atmosphere (as measured by DIMM) and in the free atmosphere (as measured by MASS). Additionally,
we consider photometric quality, light pollution, and precipitable water vapor at LCO.
The Universe appears to be expanding at an accelerating rate, driven by a mechanism called Dark Energy. The nature of Dark Energy is largely unknown and needs to be derived from observation of its effects. JEDI (Joint Efficient Dark-energy Investigation) is a candidate implementation of the NASA-DOE Joint Dark Energy Mission (JDEM). It will probe the effects of Dark Energy in three independent ways: (1) using Type Ia supernovae as cosmological standard candles over a range of distances, (2) using baryon acoustic oscillations as a cosmological standard ruler over a range of cosmic epochs, and (3) mapping the weak gravitational lensing distortion by foreground galaxies of the images of background galaxies at different distances. JEDI provides crucial systematic error checks by simultaneously applying these three independent observational methods to derive the Dark Energy parameters. The concordance of the results from these methods will not only provide an unprecedented understanding of Dark Energy, but also indicate the reliability of such an understanding. JEDI will unravel the nature of Dark Energy by obtaining observations only possible from a vantage point in space, coupled with a unique instrument design and observational strategy. Using a 2 meter-class space telescope with simultaneous wide-field imaging (~ 1 deg2, 0.8 to 4.2 μm in five bands) and multi-slit spectroscopy (minimum wavelength coverage 1 to 2 μm), JEDI will efficiently execute the surveys needed to solve the mystery of Dark Energy.
The Magellan Observatory consists of two 6.5 m telescopes located at the Las Campanas Observatory in Chile. The Magellan partner institutions are the Carnegie Institution of Washington, Harvard University, the University of Arizona, Massachusetts Institute of Technology, and the University of Michigan. The telescopes are owned and operated by Carnegie for the benefit of the consortium members. This paper provides an overview of the scientific, technical, and administrative structure of the observatory operations. A technical staff of ~23 FTEs provides on-site support of the telescopes. This group is augmented by ~3 FTEs at the Carnegie Observatories headquarters in Pasadena who concentrate mostly on upgrades or modifications to the telescopes. The observatory is operated in the "classical" mode, wherein the visiting observer is a key member of the operations team. Instrumentation is supplied entirely by the consortium members, who continue to provide significant support after instrument commissioning. An analysis of the successfulness of this model over the first five years of operation is presented.
We present results from our two year study of ground-layer turbulence as seen through the 6.5-meter Magellan
Telescopes at Las Campanas Observatory. The experiment consists of multiple, moderate resolution, Shack-
Hartmann wavefront sensors deployed over a large 16 arcminute field. Over the two years of the experiment,
the ground-layer turbulence has been sampled on eleven nights in a variety of seeing and wind conditions. On
most nights the ground-layer turbulence contributes 10% to the total visible-band seeing, although a few nights
exhibit ground-layer contributions up to 30%. We present the ground-layer turbulence on the sampled nights as
well as a demonstration of its strength as a function of field size. This information is combined with data from a
MASS-DIMM seeing monitor adjacent to the Magellan Telescopes to infer the annual ground-layer contribution
to seeing at Las Campanas.
JEDI (Joint Efficient Dark-energy Investigation) is a candidate implementation of the NASA-DOE Joint Dark Energy
Mission (JDEM). JEDI will probe dark energy in three independent methods: (1) type Ia supernovae, (2) baryon
acoustic oscillations, and (3) weak gravitational lensing. In an accompanying paper, an overall summary of the JEDI
mission is given. In this paper, we present further details of the supernova component of JEDI. To derive model-independent
constraints on dark energy, it is important to precisely measure the cosmic expansion history, H(z), in
continuous redshift bins from z ~ 0-2 (the redshift range in which dark energy is important). SNe Ia at z > 1 are not
readily accessible from the ground because the bulk of their light has shifted into the near-infrared where the sky
background is overwhelming; hence a space mission is required to probe dark energy using SNe. Because of its unique
near-infrared wavelength coverage (0.8-4.2 μm), JEDI has the advantage of observing SNe Ia in the rest frame J band
for the entire redshift range of 0 < z <2, where they are less affected by dust, and appear to be nearly perfect standard
candles. During the first year of JEDI operations, spectra and light curves will be obtained for ~4,000 SNe Ia at z < 2.
The resulting constraints on dark energy are discussed, with special emphasis on the improved precision afforded by the
rest frame near-infrared data.
The Magellan Telescopes are a collaboration between the Observatories of the Carnegie Institution of Washington (OCIW), University of Arizona, Harvard University, University of Michigan, and Massachusetts Institute of Technology (MIT) consisting of two 6.5 meter telescopes located at Las Campanas Observatory, in the Chilean Andes. The Walter Baade telescope achieved first light in September 2000 and the Landon Clay telescope started science operations in September 2002. In addition to two modified spectroscopic instruments, the Boller and Chivens Spectrograph and the Low Dispersion Survey Spectrograph (LDSS-2), four first generation instruments are now deployed at the Magellan Telescopes. Here we briefly describe the operations and performance of MagIC - a direct imaging CCD camera, MIKE - a double echelle spectrograph, PANIC - a near-IR imager, and IMACS - a multi-purpose, multi-object imaging spectrograph.
The Giant Magellan Telescope (GMT) is a joint project of a consortium of universities and research institutions to build and operate a 21.5-m equivalent aperture astronomical telescope for use at visible and IR wavelengths. This paper briefly summarizes the science goals for the project and provides an overview of the preliminary telescope and enclosure concepts and site test program. The telescope is a Gregorian design with a fast, f/0.7, primary mirror that allows a compact and stiff mount structure. The 25.3-meter diameter primary mirror consists of six off-axis 8.4-meter circular mirrors arranged in a hexagon around a center 8.4-meter mirror. The Gregorian secondary mirror is adaptive allowing two-mirror, wide-field adaptive optics. Several corrector designs have been studied for wide-field applications and one such design is shown. Instruments being considered for GMT provide a wide range of scientific capabilities. Instruments mount below the primary mirror on an instrument platform. Instrument mounting and servicing provisions are summarized.
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