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Pre-Observing	Observing	Post-Observing
Follow this link for information about pre-observing activities: proposal preparation, mask design and submission, pre-run activities, etc.	Follow this link for information about your observing run: instrument and telescope setups, scripts, software, procedures, etc.	Follow this link for information about your post-observing activities: backups, comment forms, data reduction, etc.
Trouble Shooting	Technical Pages	Index
Trouble Shooting pages and links.	Portal to the technical pages: for the initiated only!	A listing of the instrument pages.

The Echellette Spectrograph and Imager (ESI) is a visible-wavelength, faint-object, imager and single-slit spectrograph in operation at the Cassegrain focus of the Keck II telescope since 1999. ESI was designed and built at UCO/Lick Observatory under the leadership of Principal Investigator J. S. Miller and Project Manager Dave Cowley. Notable features of ESI include:

Cross-dispersed spectroscopy mode along a 20 arcsec slit at a FWHM resolving power of up to R=13,000
Low-dispersion spectroscopy mode along an 8 arcmin slit providing resolving power of 1000<R<6000
Direct imaging capability across a 2×8 arcmin field
Wide spectral range provides complete coverage from 0.39 to 1.1µm in a single exposure
Open-loop flexure compensation system maintains image stability of ±0.25 px over full rotation
High throughput

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Principal Investigator:	Joe Miller (UCO/Lick)	ESI Reference (via ADS) Sheinis et al. 2002, PASP, 114, 851.
Project Manager:	Dave Cowley (UCO/Lick)

Echellete mode optical layout.

ESI on the K2 Deck.