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Presently, the telescope is configured for the Ritchey–Chrétien (RC) focus, with an effective focal ratio of f/6.1. The mount is also configured with two large Nasmyth and 6 bent-cassegrain ports; development of instruments for these would additionally require development of a tertiary mirror.
Instrument Overview
At the RC focus, a 5-port instrument cube is installed to allow for rapid intranight swapping between instruments (~5 mins). The through-port on the cube has a 0.5º diameter flattened field of view.
Scheduling Overview
LDT is classically scheduled by semester and does not support queue observing at this time. The typical scheduling unit is half-nights, but other units may be requested depending on the needs of the science program. Additionally, a given observing program may be spread across non-consecutive nights (or even the entire semester) for scientific or weather concerns.
A Target of Opportunity (ToO) program is available for request to take advantage of both time-sensitive targets and the rapid reconfigurability of the LDT's instruments.
Instrument Overview
LDT hosts three facility instruments and a suite of visitor / PI instruments. The facility instruments are available full-time, and the others have variable availability depending on port competition and PI projects.Scheduling Overview
Facility Instruments:
Large Monolithic Imager (LMI) – A 6k x 6k optical imager (field of view is 12.3' square) whose CCD is the largest that can be made using current manufacturing techniques.
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DeVeny (Low- to Medium-Resolution Optical Spectrograph)
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LMI is typically operated binned 2x2 for 0.24" square pixels. A complete set of broadband photometric filters (Johnson-Cousins and SDSS), an astrometric V+R filter, and various stellar and cometary narrow-band filters are available.
DeVeny Optical Spectrograph – This low- to medium-resolution spectrograph is on indefinite loan from Kitt Peak National Observatory (it was known there as the White Spectrograph). DeVeny has a complement of 9 gratings that provide R ~ 500-4000, and includes various order-blocking filters. The instrument sports a 512 x 2048 CCD camera and is supported by the PypeIt spectroscopic data reduction pipeline.
Near Infrared High Throughput Spectrograph (NIHTS) – A low-resolution (R ~ 100-200) NIR spectrograph capable of covering wavelengths 0.86-2.4 microns in a single setup. NIHTS contains no moving parts and employs a single slit mask that offers 7 different width slits. This instrument may be operated simultaneously with LMI imaging via a dichroic fold flat.
Visitor / PI Instruments:
EXtreme PREcision Spectrometer (EXPRES
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QWSSI (Optical Speckle Imager)
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) – This high-resolution (R~150,000) spectrograph was built at the Yale Exoplanet Laboratory (PI: D. Fischer) for the purpose of hunting earth-sized exoplanets. It uses both a ThAr lamp and laser-frequency comb for high-precision wavelength calibrations. In addition to its key program, this instrument is available for other science.
Quad-camera, Wave-front-sensing, Six-wavelength-channel Speckle Interferometer (QWSSI) – This speckle imager was built at Lowell Observatory (PI: G. van Belle) and is an evolved from of the DSSI camera. QWSSI is capable of diffraction-limited observations of closely spaced objects.
Portable Occultation, Eclipse, and Transit System (POETS) – One of the POETS systems is generally available (contact: S. Levine) for high-speed imaging of transient events.
Rapid infrared IMAger Spectrometer (RIMAS) – This near-infrared imager / spectrograph is under development by GSFC and UMd and is scheduled to arrive in 2024. There is expected to be both low- and medium-resolution spectroscopic modes in addition to an imaging mode.