APF (Automated Planet Finder)

APF (Automated Planet Finder)
Name	Automated Planet Finder
Acronym	APF
Operator	Lick Observatory
Location	Mount Hamilton, California
Altitude	1283 m
Telescope type	Optical reflecting telescope
Diam	2.4 m
Established	2013

APF (Automated Planet Finder) The Automated Planet Finder is a dedicated exoplanet-hunting facility built to perform high-cadence precision radial velocity measurements. The instrument pairs a 2.4-meter optical telescope with a stabilized spectrograph to monitor nearby Kepler and TESS target stars, serving programs associated with UC Santa Cruz, UC Berkeley, and NASA teams. It operates within the network of ground-based facilities that includes W. M. Keck Observatory, Calar Alto Observatory, and ESO sites to provide complementary follow-up for transit surveys and astrometric programs.

Overview

The project was conceived as part of coordinated follow-up for space missions such as Kepler and TESS, and as a partner to facilities like HARPS and HIRES for precision spectroscopy. The observatory emphasizes long-term stability for radial velocity work to detect low-mass planets around nearby dwarfs such as those listed in catalogs maintained by SIMBAD and Gaia. The APF's mission intersects programs led by teams from UC Santa Cruz, NASA Ames, and collaborators at institutions like Carnegie Institution for Science and MPIA.

Instrumentation and Design

The facility combines a 2.4-meter telescope optical system with a fiber-fed, temperature-controlled echelle spectrograph modeled on designs used at Lick Observatory and influenced by spectrographs at ESO installations. The spectrograph achieves high resolution using a blaze echelle and vacuum enclosure similar to those in HARPS and ESPRESSO systems developed with input from teams at Geneva Observatory and Leiden Observatory. The instrument shares heritage with spectrographs used at Keck Observatory and benefits from engineering practices refined at JPL and by optical vendors serving MIT and Caltech groups. Detectors and controllers incorporate flight-qualified techniques from JPL and industry partners associated with Lockheed Martin and Raytheon.

Observing Modes and Operations

APF operates largely autonomously under software scheduling influenced by operational frameworks from LCOGT and robotic systems used by Pan-STARRS and ZTF. Observing modes prioritize high-cadence radial-velocity sequences for bright nearby stars cataloged by Hipparcos and Gaia, and time-critical follow-up of transits flagged by TESS and Kepler. Nightly operations coordinate target lists from groups at UC Santa Cruz, UC Berkeley, Carnegie Institution for Science, and U.S. federal programs administered by NASA. The control software integrates weather and seeing monitors akin to systems at Palomar Observatory and Kitt Peak National Observatory.

Scientific Goals and Discoveries

The primary science objective is detection and characterization of exoplanets, with emphasis on low-mass planets in short- to intermediate-period orbits around nearby M-dwarf and K-dwarf stars. APF complements transit photometry from TESS and atmospheric characterization campaigns planned with JWST and HST. Results from APF contribute to catalogs maintained by NASA Exoplanet Archive and inform target selection for missions such as WFIRST and facilities like ALMA and Subaru Telescope. Discoveries include radial-velocity detections that corroborate transit candidates and refine mass measurements for systems previously observed by teams at IfA and CfA.

Data Processing and Analysis

Data reduction pipelines developed for APF use algorithms similar to those employed by HARPS and HIRES, incorporating wavelength calibration strategies derived from iodine cell techniques and laser-frequency comb concepts pioneered in collaborations with NIST and CU Boulder. Analysis workflows apply periodogram methods used in studies by groups at University of Geneva and statistical frameworks shaped by researchers at Princeton University and MIT. Processed radial velocities are archived for access by teams at Caltech, Stanford University, and international partners including MPIA and IAC.

Location and Facilities

APF is situated on Mount Hamilton at Lick Observatory, sharing infrastructure with telescopes maintained by University of California and visitor facilities associated with San Jose State University outreach. The site benefits from local seeing and historical links to observatories such as Palomar Observatory and personnel exchanges with institutions like UC Santa Cruz and UC Berkeley. Support roles involve engineers and scientists from Lick Observatory staff and collaborators at NASA Ames and private partners.

History and Development

The project was funded through partnerships involving University of California, private benefactors, and NASA-related programs, drawing on expertise from instrument groups at UC Santa Cruz, UC Berkeley, Carnegie Institution for Science, and JPL. Commissioning occurred in the early 2010s with science operations ramping up alongside Kepler follow-up; subsequent upgrades paralleled developments at ESO and instrument programs at Keck Observatory. Ongoing collaborations extend to international centers such as MPIA, Geneva Observatory, and IfA to maximize synergy with space missions like TESS, JWST, and planned observatories.

Category:Telescopes