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The physics of molecular vibration causes absorption spectra of atmospheric molecules to be a group of approximately periodic fine lines. This is fortuitous for detecting exoplanet biosignificant molecules, since it approximately matches the periodic sinusoidal transmission of an interferometer. The series addition of a 0.6 cm interferometer with a dispersive spectrograph creates moire patterns. These enhance detection by several orders of magnitude for initially low resolution spectrographs. We simulate the Gemini Planet Imager integral field spectrograph observing a telluric spectrum of native resolutions 40 and 70 for 1.65 and 2 micron bands– too low to resolve the fine lines. The interferometer addition increases the detectability of the molecular signal, relative to photon noise, to a level similar to a R=4400 (at 1.65 micron) or R=3900 (at 2 micron) spectrograph.

We present an updated optical and mechanical design of NEWS: the Near-infrared Echelle for Wide-band Spectroscopy (formerly called HiJaK: the High-resolution J, H and K spectrometer), a compact, high-resolution, near-infrared spectrometer for 5-meter class telescopes. NEWS provides a spectral resolution of 60,000 and covers the full 0.8-2.5 micron range in 5 modes. We adopt a compact, lightweight, monolithic design and developed NEWS to be mounted to the instrument cube at the Cassegrain focus of the the new 4.3-meter Discovery Channel Telescope., Comment: Proc. SPIE 9908, Ground-based and Airborne Instrumentation for Astronomy VI, 99086M (August 9, 2016)

We describe demonstrations of remarkable robustness to instrumental noises by using a multiple delay externally dispersed interferometer (EDI) on stellar observations at the Hale telescope. Previous observatory EDI demonstrations used a single delay. The EDI (also called “TEDI”) boosted the 2,700 resolution of the native TripleSpec NIR spectrograph (950-2450 nm) by as much as 10x to 27,000, using 7 overlapping delays up to 3 cm. We observed superb rejection of fixed pattern noises due to bad pixels, since the fringing signal responds only to changes in multiple exposures synchronous to the applied delay dithering. Remarkably, we observed a ~20x reduction of reaction in the output spectrum to PSF shifts of the native spectrograph along the dispersion direction, using our standard processing. This allowed high resolution observations under conditions of severe and irregular PSF drift otherwise not possible without the interferometer. Furthermore, we recently discovered an improved method of weighting and mixing data between pairs of delays that can theoretically further reduce the net reaction to PSF drift to zero. We demonstrate a 350x reduction in reaction to a native PSF shift using a simple simulation. This technique could similarly reduce radial velocity noise for future EDI’s that use two delays overlapped in delay space (or a single delay overlapping the native peak). Finally, we show an extremely high dynamic range EDI measurement of our ThAr lamp compared to a literature ThAr spectrum, observing weak features (~0.001x height of nearest strong line) that occur between the major lines. Because of individuality of each reference lamp, accurate knowledge of its spectrum between the (unfortunately) sparse major lines is important for precision radial velocimetry.

We present the science motivation, design, and on-sky test data of a high-throughput fiber coupling unit suitable for automated 1-meter class telescopes. The optical and mechanical design of the fiber coupling is detailed and we describe a flexible controller software designed specifically for this unit. The system performance is characterized with a set of numerical simulations, and we present on-sky results that validate the performance of the controller and the expected throughput of the fiber coupling. This unit was designed specifically for the MINERVA array, a robotic observatory consisting of multiple 0.7 m telescopes linked to a single high-resolution stabilized spectrograph for the purpose of exoplanet discovery using high-cadence radial velocimetry. However, this unit could easily be used for general astronomical purposes requiring fiber coupling or precise guiding.

We present the science drivers, design requirements and a preliminary design for a high-resolution, broad- bandwidth, slit-fed cross-dispersed near-infrared spectrometer for 5-meter-class telescopes. Our concept, called the High-Resolution J, H and K Spectrometer, or HiJaK, utilizes an R6 echelle in a white-pupil design to achieve high resolution in a compact configuration with a 2048 x 2048 pixel infrared detector. We present a preliminary ray-traced optical design matched to the new 4.3-meter Discovery Channel Telescope in Happy Jack, Arizona. We also discuss mechanical and cryogenic options to house our optical design.

The TripleSpec Exoplanet Discovery Instrument (TEDI) is optimized to detect extrasolar planets orbiting mid-to-late M dwarfs using the Doppler technique at infrared wavelengths. TEDI is the combination of a Michelsoninterferometer and a moderate-resolution near-infrared spectrograph, TripleSpec, mounted on the Cassegrainfocus of the Palomar 200-inch Hale Telescope. Here we present results from observations of a radial velocitystandard star and a laboratory source over the past year. Our results indicate that focus eects within theinterferometer, combined with non-common-path errors between the ThAr calibration source and starlight, limitour performance to several 100 m/s. An upgraded version of TEDI, TEDI 2.0, will eliminate this behavior bymixing ThAr with starlight in a scrambled “ber before a redesigned interferometer with minimal focal eects.Keywords: Extrasolar Planets, Radial Velocity, Infrared Astronomy 1. MOTIVATION Eciently attaining 1 m/s of radial velocity (RV) precision with near-infrared (NIR) spectroscopy enables thefollowing: (1) detection of potentially-habitable Earth-mass and larger exoplanets orbiting nearby mid-to-lateM dwarf stars too faint for visible radial velocimetry, (2) expansion of the number of early M dwarfs targetableby visible RV surveys to those at greater distances increasing the yield of detected potentially-habitable planets,(3) veri“cation and mass-measurement of exoplanet transit candidates observed to transit such M dwarfs, (4)detection of exoplanets around active stars and young stars with too much visible RV jitter

The TEDI (TripleSpec - Exoplanet Discovery Instrument) is the first instrument dedicated to the near infrared radial velocity search for planetary companions to low-mass stars. The TEDI uses Externally Dispersed Interferometry (EDI), a combination of interferometry and multichannel dispersive spectroscopy. We have joined a white-light interferometer with the Cornell TripleSpec (0.9 - 2.4 μm) spectrograph at the Palomar Observatory 200" telescope and begun an experimental program to establish both the experimental and analytical techniques required for precision IR velocimetry and the Doppler-search for planets orbiting low mass stars and brown dwarfs.

We report the performance of Triplespec from commissioning observations on the 200-inch Hale Telescope at Palomar Observatory. Triplespec is one of a set of three near-infrared, cross-dispersed spectrographs covering wavelengths from 1 - 2.4 microns simultaneously at a resolution of ~2700. At Palomar, Triplespec uses a 1×30 arcsecond slit. Triplespec will be used for a variety of scientific observations, including moderate to high redshift galaxies, star formation, and low mass stars and brown dwarfs. When used in conjunction with an externally dispersed interferometer, Triplespec will also detect and characterize extrasolar planets.

Externally Dispersed Interferometry (EDI) is the series combination of a fixed-delay field-widened Michelson interferometer with a dispersive spectrograph. This combination boosts the spectrograph performance for both Doppler velocimetry and high resolution spectroscopy. The interferometer creates a periodic comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. Both regular and high-frequency spectral components can be recovered from the data--the moire component carries additional information that increases the signal to noise for velocimetry and spectroscopy. Here we present simulations and theoretical studies of the photon limited Doppler velocity noise in an EDI. We used a model spectrum of a 1600K temperature star. For several rotational blurring velocities 0, 7.5, 15 and 25 km/s we calculated the dimensionless Doppler quality index (Q) versus wavenumber v. This is the normalized RMS of the derivative of the spectrum and is proportional to the photon-limited Doppler signal to noise ratio.

We present the design for a near-infrared (JHK) fringe tracker to be used at the CHARA Array, a long baseline optical interferometer located at Mount Wilson Observatory. The CHARA Michigan Phase-tracker (CHAMP) is being fabricated and tested at the University of Michigan and will be transported to the CHARA Array for general use. CHAMP is separate from the science combiners and can therefore be optimized for fringe tracking. It will modulate around fringe center by 1-2λ at up to 500 Hz and calculate phase offsets in real-time using a modified 'ABCD' method . Six pair-wise Mach-Zehnder combiners will phase the entire Array. We give an overview of the optical layout and discuss our design strategy. Components such as the path-length modulators, low-OH fiber transport system, 1024x1024 HAWAII-1 detector, and control computer are discussed.