The Ionospheric Connection Explorer (ICON) is a NASA Heliophysics Explorer Mission designed to study the ionosphere. ICON will examine the Earth's upper atmosphere to better understand the relationship between Earth weather and space-weather drivers. ICON will accomplish its science objectives using a suite of 4 instruments, one of which is the Extreme Ultraviolet Spectrograph (EUV). EUV will measure daytime altitude intensity profile and spatial distribution of ionized oxygen emissions (O+ at 83.4 nm and 61.7 nm) on the limb in the thermosphere (100 to 500 km tangent altitude). EUV is a single-optic imaging spectrometer that observes in the extreme ultraviolet region of the spectrum. In this paper, we describe instrumental performance calibration measurement techniques and data analysis for EUV. Various measurements including Lyman-α scattering, instrumental and component efficiency, and field-of-view alignment verification were done in custom high-vacuum ultraviolet calibration facilities. Results from the measurements and analysis will be used to understand the instrument performance during the in-flight calibration and observations after launch.
Techniques are described for tolerancing a radial velocity spectrometer system within Zemax, including: how to set up and verify the tolerancing model, performance metrics and tolerance operands used, as well as post- Zemax analysis methods. Use of the tolerancing model for various analyses will be discussed, such as: alignment sensitivity, radial velocity sensitivity, and sensitivity of the optical system to temperature changes. Tolerance results from the Keck Planet Finder project (a precision radial velocity spectrometer of asymmetric white pupil design) will be shown.
A method using non-sequential Zemax to produce a pixelated synthetic spectrum is described. This simulation was developed for the Keck Planet Finder (KPF) instrument, and will prove useful for engineering performance analyses (stability, stray light, order cross-talk, distortion, etc.). It has also provided a set of synthetic spectra to be used during the development of the data pipeline. Various aspects concerning the construction of the spectrum are described, including: converting a model from sequential to non-sequential Zemax, the creation of Zemax coating files for echelle blaze functions, and the generation of spectrum source files (solar, thorium-argon, incandescent, Fabry-Perot etalon and laser frequency comb).
KPF is a fiber-fed, high-resolution, high-stability spectrometer in development at the UC Berkeley Space Sciences Laboratory for the W.M. Keck Observatory. The instrument is designed to characterize exoplanets via Doppler spectroscopy with a single measurement precision of 0.5ms-1 or better, however its resolution and stability will enable a wide variety of astrophysical pursuits. KPF will have a 200mm collimated beam diameter and a resolving power of >80,000. The design includes a green channel (440nm to 590 nm) and red channel (590nm to 850 nm). A novel design aspect of KPF is the use of a Zerodur optical bench, and Zerodur optics with integral mounts, to provide stability against thermal expansion and contraction effects.