1. Classical Echelle Spectrograph for the ARC 3.5-m Telescope at Apache Point Observatory, NM

I am working with collaborators at NMSU (Nancy Chanover, PI) and JHU (Steve Smee, Robert Barkhouser, Randy Hammond) on the design (see Wilson et al. 2024) of a new, classical, optical echelle spectrograph for the Astrophysical Research Consortium (ARC) 3.5-m Telescope at Apache Point Observatory in New Mexico.  Our vision is to replace the venerable ARCES spectrograph, in service for 20 years, with a new instrument using the latest innovations in high-resolution spectrograph design to provide maximal throughput across the wavelength range of 340 nm --- 1000 nm.

As of Summer 2025 we are close to preliminary design level for a spectrograph with baseline resolution R ~ 32,000 for a 1.7 arcsec slit (4.5 pixel sampling).  Featuring a white pupil design, the instrument would have dedicated blue and red arms with prism cross-dispersion and refractive cameras.  The slit length is approx. 6 arcsec.

A slit change mechanism would also allow the use of a 1.3 arcsec slit to be used along with a high-speed tip-tilt image stabilization mechanism in the fore-optics.  The tip-tilt system would minimize PSF broadening from sources such as telescope vibration, tracking errors, and, to a lesser extent, atmospheric tip-tilt.  This slit would provide resolution R ~ 40,000.   A "Bowen-Walraven" two-slit image slicer would also be available to provide resolution R ~ 64,000.  The fore-optics will also include an Atmospheric Dispersion Corrector, Slit Viewer, and dedicated Calibration System.

2. Simons Observatory Operations Support

I am working with the Simons Observatory Operations Team to help with the logistics of spare parts, instrument maintenance, and shipping in support of the observatory instruments.  Located at 17,000 ft in Chile's Atacama Desert, this experiment operates at an environmentally challenging site!

3. Radial Velocity Upgrades to APOGEE Spectrographs

For SDSS-V, we commissioned multiple external upgrades, pioneered by the Penn State precision radial velocity instrumentation group, to both APOGEE spectrographs to improve the instrument radial velocity precision from approx. 100 m/sec to 30 m/sec.  The upgrades, described in Wilson et al. 2022, consist of: 

• Fabry-Perot Interferometric calibration sources to provide a picket fence of spectral lines with uniform spacing and intensity for precision wavelength calibration.
• Back Pressure Regulators control the back pressure seen by the internal LN₂ tanks to help isolate the tanks from varying atmospheric pressure.  This stabilizes the internal temperatures of the cryogenically cooled instruments.
• Octagonal Fibers in series with the fibers going to the instrument from the telescope to minimize motion of the near-field image at the ends of the fibers inside the instrument at the pseudo-slit.