Hello! My name is Ryan Rubenzahl (he/him). I use the radial velocity (RV) technique to understand the demographics of exoplanets in our galaxy. I'm particularly motivated to advance RV capabilities to be sensitive to Earth-Sun analogs. Towards this, I built the "Solar Calibrator" to study stellar activity up-close on our nearest Sun-like star.

I am currently rebuilding my website (because I upgraded Hugo and it broke everything) -- stay tuned as I transfer and update to this new site.

Me, pointing at my PhD thesis instrument, the
                                    Solar Calibrator (SoCal).

Research Highlights

  • KPF Project Manager
                                        Kodi Rider assembling the main spectrograph at the Berkeley Space Sciences Laboratory.


    I'm a part of the the Keck Planet Finder instrument and science team: check out our commissioning progress!

  • The Solar Calibrator (SoCal).


    I built the Solar Calibrator to study stellar activity on the Sun with KPF.

  • The angle
                                        between a planet's orbital plane and its host stars rotation axis is called the obliquity.


    I use RV spectrographs to measure the (mis)alignment between an exoplanet's orbit and its host star.


  • Showing a local
                                        Pasadena family the November 11, 2019 Mercury transit through my telescope + solar filter

    I regularly participate in our astronomy outreach program at Caltech, including stargazing events on campus, on sidewalks in downtown Pasadena, and in National Parks like Death Valley.

  • I gave a public lecture for CaltechAstro outreach on our YouTube channel about how radial velocity spectrographs work and why stellar activity is such a big problem.

Community Organizing

  • CGPU logo

    I'm a founding member of Caltech Grads and Postdocs United, the active effort at Caltech to form a labor union for graduate and postdoctoral researchers. Please reach out if you have unionization questions and/or are interested in forming a higher-ed labor union at your institution!

  • Pasadena Measure H

    I believe we can all do our best work when economic barriers to living and working in the US are removed. That's why I and other Caltech grad students helped collect over 15,000 signatures to win the strongest rent control and just-cause eviction protections in the country, right here in Pasadena CA.