The Thacher Observatory

The Thacher Observatory

In December of 2016, the newly renovated Thacher Observatory was unveiled. The Thacher Observatory houses a PlaneWave CDK-700 telescope which has a 0.7m aperture and a fully robotic dome. The observatory operates in a fully automated fashion using a flexible dispatch scheduler.

The transformation of the Observatory into a state-of-the-art, research-grade facility was part of a wider expansion of the astronomy program at Thacher and the result of years of hard work and vision by Dr. Chris Vyhnal, the chair of the Science DepartmentDr. Jon Swift, director of the Thacher Observatory, and many others.

The Observatory has a long and interesting history stretching back to 1965 when UCLA and Caltech brought the facility to campus as part of a Summer Science Program for high-achieving students hosted at Thacher. After the departure of the SSP and through the passing of years, the observatory went into disuse. But since its renovation, it has offered a new generation of students in astronomy, data science, and computer science courses profound applied-learning opportunities once again. Among these opportunities is the chance to contribute to Dr. Swift’s ongoing NASA-funded research of eclipsing binaries and transiting exoplanets, which he is undertaking in collaboration with colleagues at the Boston University and Harvard.


Thacher has an active astronomical research program with students working at the forefront of astrophysics research. This research is done in collaboration with partners across the globe including teams at the Boston University, the University of California at Santa Cruz, Harvard, and the Las Cumbres Observatory. We are dedicated to providing an authentic experience where students engage fully with pressing problems in astronomy and build breadth and depth of understanding while gaining invaluable experience working in small teams toward meaningful goals.

The 2018-19 research team  led by Dr. Swift, includes seniors, Colin, George, Julien, Piper, Alejandro, and Yao.

Low-mass Stars and Their Planets

The lowest mass stars—called red dwarfs—comprise about 70 percent of all the stars in the entire Galaxy. However, red dwarfs are cool, dim, and emit most of their radiation at infrared wavelengths, making them difficult to study and understand. Moreover, these stars tend to have a high frequency of planets. Therefore the populations of planets around red dwarfs give important insights into how planets form across the Galaxy.

One of our main objectives at the Thacher Observatory is to leverage accurate measurements enabled by our new facility to measure the properties of exoplanets around low-mass stars. However, an accurate characterization of an exoplanet depends on an accurate characterization of its host star. Therefore we are also engaged in ongoing studies of low mass stars to better understand the relationship between their masses, radii, and effective temperatures through the identification and measurements of eclipsing binary systems.

Tabby's Star

Touted as the “most mysterious star in the Galaxy,” Tabby’s Star appears to be a normal star with about 40 percent more mass than the Sun. However, in 2016, Dr. Tabetha Boyajian (a.k.a. Tabby) discovered that this star behaves in a way that has confounded astrophysicists for years. Thacher students attended a public science talk hosted by the Las Cumbres Observatory in Goleta, CA in 2017, and ever since we have been engaged in the long term monitoring of this strange star in several different parts of the visible spectrum using the Thacher Observatory. The Thacher Observatory data has been published in the Astrophysical Journal, and Thacher students presented our results at a press release conference at the 232nd meeting of the American Astronomical Society in June, 2018.

NASA Follow-up Observation Program, Sub-group 1:

The Transiting Exoplanet Survey Satellite (TESS) is a NASA satellite mission designed to be the next step in the search for planets outside of our solar system, including those that could support life. The mission will find exoplanets that periodically block part of the light from their host stars, events called transits. TESS will survey 200,000 of the brightest stars near the sun to search for transiting exoplanets. TESS launched on April 18, 2018, and has been successfully collecting data since shortly thereafter.

Recently, students at Thacher have demonstrated our in-house expertise for exoplanet observations to the TESS team and garnered our acceptance into the TESS Follow-up Observing Program, sub-group 1 (TFOP SG1). For this program, Thacher Observatory has dedicated several hours a week to identifying, confirming, and in some cases, improving on the information that TESS provides. TESS observations of the northern hemisphere will start in August 2019 when we will begin our follow-up studies in earnest.

Custom Automation Software for the Thacher Observatory

Although we currently use robust automation software for nightly observations, there are often times that we need to conduct specialized and highly nuanced observations. For this reason, and also to expand the educational impact of the observatory, students at Thacher have embarked on a large computer science project to write a custom automation software for our observatory. We are doing this in collaboration with the Miniature Exoplanet Radial Velocity Array ( MINERVA), headquartered at Harvard University.

List of 1 members.

  • Dr. Jonathan Swift 

    Director of the Thacher Observatory and Mathematics, Physics, and Astronomy Teacher
    Extension 245
    University of California, Berkeley - PhD
    University of California, Los Angeles - BS

Astronomy Alumni

List of 13 items.

  • Justin '13*

  • Erich ’14*

  • Douglas ’16

  • Liam ’17

  • Asher ’17

  • Katie ’18

  • Nick ’18

  • Alejandro ’19

  • George ’19

  • Julien ’19

  • Piper ’19

  • Yao ’19

  • * These students worked with Dr. Swift while he was working at Caltech, before he moved to Thacher in December 2014.