WIYN Observatory


NEID (NUH-eed or NOO-id, rhymes with “fluid”), which gets its name from the Tohono O'odham word meaning "to see", is funded by the joint NASA/NSF Exoplanet Exploration Program (or NN-EXPLORE).

NEID consists of two principal parts. The port adaptor (provided by the University of Wisconsin) is mounted on the Bent Cassegrain port at WIYN. It is used to acquire and guide on a target star, precisely maintaining the stellar centroid on a science fiber in the focal plane. Other nearby fibers gather simultaneous light from the sky. Calibration light can also be sent to NEID via the port adaptor. The fibers feed their light to a new spectrograph room built by WIYN on the ground floor of the observatory. The room ensures a stable environment for the spectrograph. The NEID spectrograph is built by Penn State University (Suvrath Mahadevan, PI). It is sealed in a vacuum chamber to maintain the optics at a stable temperature (variations <1 mK) and isolated from outside disturbances over NEID's 5-year program baseline.

NEID Characteristics

Spectrograph Characteristics

  • Echelle design with prism cross-disperser
  • Continuous broadband wavelength coverage (380-930 nm)
  • 9K x 9K e2v CCD with 10 micron pixels
  • Choice of two science fibers for two resolution modes: One is the high resolution (HR) mode (R>110,000) for bright targets (V<12). The other, a high-efficiency (HE) mode (R~60,000), is designed for fainter stars or poor observing conditions.
  • Spectrograph throughput is >40% at 500 nm for a mean system throughput of 5.6% over the full bandpass in HR mode
  • Chromatic exposure meter gathers a time series of low-resolution spectra in parallel to each science spectrum, enabling barycentric corrections to <1 cm/s
  • Ultra-precise wavelength calibration via multiple sources, including a laser frequency comb
  • Additional simultaneous calibration via the laser frequency comb can be requested (a Fabry-Perot etalon will be used as a backup if the LFC is not available on a given night, but cannot be requested)

System Characteristics

  • Baseline requirement for single point, long-term radial velocity precision is 50 cm/s
  • Higher level requirement for the same is 27 cm/s
  • Limiting magnitudes: 3.5 < V < 16
  • Zenith distance range: 5 degrees < ZD < 70 degrees
  • Fiber size on sky is 0.9” for HR and 1.5" for HE mode
  • Queue designed for radial velocity work on exoplanet host stars with the means to schedule observations relative to periodic ephemerides
  • Queue designed for science-based prioritization as specified by the TAC or a program's PI. The goal is that PIs will operate dynamic observing programs with the ability to alter observation requests (e.g., exposure lengths, timing of observations) and targets during the semester
  • Nighttime calibration data acquired for reduction of data from all programs if needed (charged to the program); standard sets of daytime calibrations taken just before and after the observing night (not charged to the program)
  • Operational over a wide range of seeing and transparency conditions with appropriate choice of target and spectral resolution

Data Products

All data taken with NEID will be processed through the NEID data reduction pipeline run daily at NExScI (https://neid.ipac.caltech.edu/search.php). The following data products will be available via the NEID archive at NExScI:

The metadata (source, observation time, exposure time, release date) for all observations will be available as soon as the data are ingested in the NEID archive. The data products will be available after a proprietary period, the GO proprietary period is 18 months.

NEID obtains a standard calibration sequence every night and morning, which includes bias, flats, wavelength calibrators. Spectrophotometric and telluric standards will not be taken as standard products; proposers should request these (and account for them in their time request) if they are desired.

NEID also observes a small set of RV standard stars every night, and the raw and reduced data products will be available to the community with zero proprietary period. The standard star list includes 9 targets, of which 1-3 will be observed every night NEID operates.

NEID also takes ~300 spectra of the Sun every clear day using a dedicated solar feed (funded by the Heising Seimens Foundation). These data are processed through the NEID data reduction pipeline at NExScI and available to the public with no proprietary period. See Lin et al. 2022 for details on the solar feed and its early performance.

NEID Splinter Session at the January 2019 AAS

A lot of useful information about NEID was presented at the NNEXPLORE NEID splinter session, held at the recent AAS meeting in Seattle. Suvrath Mahadevan, NEID PI at PSU presented an overview and current status; Jason Wright, Project Scientist at PSU focused on the exciting science NEID can deliver. Jayadev Rajagopal, WIYN Scientist, summarized the Operations plan (including the queue); Rachel Akeson from NEXScI presented the data archive and pipeline capabilities, John Callas, Project Manager at NASA/JPL finished up with a policy overview.

Slides from that session can be found here.

NSF University of Wisconsin Indiana University Purdue University Pennsylvania State University Princeton University

Last modified: 27-Sep-2023 11:50:05 MST