Jeffrey Richard Kuhn

Jeffrey Richard Kuhn (born November 01, 1957) is an American physicist and professor of astronomy at The University of Hawai'i. He has made advancements in several fields in astrophysics and the search for life in the universe.
Kuhn is known for his contributions to the development of optical instruments and unusual telescopes, astronomical signal detection algorithms, and infrared and polarimetric detector systems. This includes the Princeton Solar Distortion Telescope (PSDT) the National Solar Observatory (NSO) Precision Solar Photometric Telescope (PSPT), the University of Hawai'i Solar Observatory for Limb Active Regions and Coronae (SOLARC), and design contributions toward the Daniel K. Inouye Solar Telescope (DKIST) and the Giant Magellan Telescope (GMT) concepts. Telescopes Kuhn has conceived are under construction or planning now include the PLANETS telescope|Polarized Light from Atmospheres of Nearby Extra-Terrestrial Systems (PLANETS) and the ExoLife Finder telescopes (ELF and MiniELF).
He spearheaded the development of the University of Hawai'i’s Maui Advanced Technology Research Centre of the Institute for Astronomy (Hawaii)|Institute for Astronomy. Kuhn is also the primary co-founder of the PLANETS Foundation, Colossus Project, and MorphOptic, Inc.
== Early life and education ==
Kuhn was born on November 01, 1957, in Columbus, Ohio. In 1972, he was the national Academic Games Wff’n Proof champion. He completed his bachelor of arts degree in physics and mathematics from Kalamazoo College in 1977. He received his master of science degree and doctorate in physics in 1979 and 1981 from Princeton University with Robert Dicke. He was a professor at Princeton until 1986, then a professor at Michigan State University until 1997. From 1992 until 1997, he also held the position of Astronomer with the National Solar Observatory at Sunspot, New Mexico. In 1997, he joined the Institute for Astronomy (IfA) in Honolulu and was the IfA associate director and director of the IfA/Maui division until 2015. Kuhn has been a visiting senior professor at Lyon University, National Astronomical Observatory of Japan (NAOJ), University of Nice, University of Paris, and Institute for Particle Physics and Astrophysics of ETH Zürich, Switzerland.
== Career ==
=== Scientific contributions ===
Kuhn has made notable scientific contributions in several astrophysics fields while developing relevant instruments and algorithms. He is known for his early creation of infrared instruments for solar and solar coronal Astronomical spectroscopy|spectroscopy and spectropolarimetry and for his use of satellite experiments for understanding small changes in the Sun’s shape and brightness. His work to improve telescopes for observing faint objects near overwhelmingly bright sources extends from solar to nighttime instruments.
=== Astrophysical detectors and telescopes ===
File:Mt. Wilson Observatory in the San Gabriel Mountains of Los Angeles County. USDAUSFS photo. (33896579074).jpg|thumb|Mt. Wilson Observatory
Kuhn, with Dicke and Libbrecht, developed the Princeton Solar Distortion Telescope (PSDT) for observing the limb of the Sun from the Mount Wilson Observatory. 
He developed one of the first IR array detectors for solar studies. With Lin, Kuhn also built an ultra-stable magnetic field tunable, imaging optical filter, that used the Birefringence properties of isotopically pure potassium.
Kuhn designed and built several IR instruments that were used to observe the Sun during Eclipse|eclipses. This included a high-resolution IR coronal spectrometer for the Altiplano|Chilean Altiplano eclipse in 1994 where his group detected new coronal IR emission lines in the first high resolution, extended wavelength coronal IR spectrum.
Kuhn and collaborators built an IR imaging spectrograph to look for a postulated solar coronal emission line near a 5-micron wavelength with extreme diagnostic potential for measuring coronal magnetic fields. This instrument was used to observe the 1998 eclipse from an open C130 airplane, staged from Panama. Kuhn and collaborators built an infrared imaging fiber spectropolarimeter that they took to the Libyan Desert|Libyan Sahara desert for the eclipse in 2006.
Kuhn, with Hawley, initiated a campaign to build the world’s largest off-axis astronomical telescope to improve the intrinsic photometric dynamic range of night-time observations.
File:Daniel K. Inouye Solar Telescope.jpg|thumb|Daniel K. Inouye Solar Telescope
He designed and led the development of the Precision Solar Photometric Telescope (PSPT) that was used for dedicated long-term photometry measurements of the Sun’s disk for the world solar community.
Kuhn and Beckers initiated an effort to build a large off-axis solar telescope called CLEAR “Coronagraphic and Low Emissivity All-Reflecting telescope.” The concept eventually became the NSO-led project called the Advanced Technology Solar Telescope (ATST) and then the Daniel K. Inouye Solar Telescope (DKIST) on Haleakala.
With NASA funding, Kuhn built the Solar Observatory for Limb Active Regions and Coronae (SOLARC) - a 0.5m off-axis, unobscured solar coronagraph on Haleakala. With NSO as the lead institution, Kuhn and collaborators initially submitted the proposal to the National Science Foundation (NSF) for the Advanced Technology Solar Telescope for Haleakala, a 4m off-axis coronagraph with an off-axis optical design inspired by SOLARC. In 2010, The NSF granted this award in excess of $300 million.
In 2015, Kuhn initiated and led the design and construction of a sensitive cryogenic near-infrared spectropolarimeter (CryoNIRSP) for DKIST (first light) coronal Magnetometer|magnetometry. With Hawai'i collaborators, Kuhn introduced a telescope concept that looks very similar to the pending Giant Magellan Telescope.
File:AEOS3 lg.jpg|thumb|Haleakala Observatory — AEOS 3.67-meter telescope
Kuhn, with Harrington, led the implementation of the 3.67 m Advanced Electro Optical System Telescope|Advanced Electro-Optical System (AEOS) 3.67m telescope’s high-resolution visible and infrared spectropolarimeter on Haleakala (HiVIS).
Kuhn, with international collaborators and the PLANETS Foundation, is building a prototype large coronagraphic telescope for circumstellar environment and exoplanet studies on Tenerife. This “ExoLife Finder” (MiniELF) will be completed in 2024, with an ELF telescope possible by 2030.
=== Physics of the sun ===
Kuhn’s PhD at Princeton (physics) explored the connection between the Sun’s surface turbulence, large scale velocity correlations, and global solar oscillations. He obtained miles of 35mm photographic film that were digitized and analyzed to recover the spatial-temporal velocity of the Sun’s disk. He measured the 3K solar limb temperature variations related to convection-rotation correlations and the solar cycle. These measurements accounted for Dicke’s earlier, larger, solar oblateness measurement.
With Lin, his first infrared (IR) measurements showed that the Sun’s supergranulation thermal radiation signature was not consistent with expected solar turbulence and likely not a simple convection phenomenon.
Kuhn and collaborators advanced studies of the largely unknown coronal IR spectrum using IR arrays to describe large wavelength intervals of the coronal spectrum for the first time.
With years of PSDT data and the data from the then-new field of helioseismology, Kuhn showed that the solar-cycle luminosity and solar irradiance variations were not equivalent and that the solar luminosity changes could be explained from solar-cycle changes in the helioseismologically-derived solar oscillation frequencies and variations within the solar interior.
File:Solar Dynamics Observatory 1.jpg|thumb|Solar Dynamics Observatory Satellite
Kuhn and collaborators devised algorithms that enabled NASA's Solar and Heliospheric Observatory Michelson Doppler Imager (SOHO/MDI) to attain solar Astrometry|astrometric precision orders of magnitude higher than ever achieved. With these tools, Kuhn and collaborators made the most sensitive measurements of possible solar radius changes using NASA Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) starting in the late ‘90s. From the 1990s to the present, Kuhn and his collaborators have used these satellite-based measurements to study the shape and brightness of the Sun and to detect small changes in the Sun's limb with unprecedented accuracy. These satellite data were also used by Kuhn and his group to demonstrate that the Sun is the roundest natural object known.
Most recently they solved the longstanding problem of why the outer 5% of the Sun rotates 5% slower than the deeper layers. Their group studied the very outer layer of the Sun using the HMI satellite limb data and saw microarcsecond oscillations at the Sun’s edge that trace its rotation.
File:Haleakala Observatory Maui (45015823284).jpg|thumb|Haleakalā Observatory with DKIST (left) and AEOS Telescope (right)
With Lin and Coulter, Kuhn created the first (high sensitivity) magnetogram of coronal magnetic fields. It had a sensitivity better than one gauss using this SOLARC telescope on Haleakalā Observatory|Haleakala Observatory. SOLARC was an off-axis optical/Optical telescope|IR telescope that demonstrated how intrinsically faint phenomenon could be detected against bright backgrounds. Kuhn and collaborators found a faint neutral helium coronal atmosphere, likely created by the interaction of circumsolar dust and the Helium solar wind.
=== Gravitation ===
Kuhn demonstrated that the classical Newton's law of universal gravitation|gravitational force law could be modified (consistent with observations) and reconciled with the 1980’s-era galaxy, galaxy cluster, and cosmological-scale astronomical velocity observations, without postulating invisible dark matter.
Using the Sun as a gravitational wave detector, Kuhn and Boughn derived limits on possible cosmic background gravitational radiation from observations of solar oscillations. He also constrained the existence of postulated “Fifth force|fifth-force” gravitation-like interactions using helioseismology mode frequencies.
=== Stars and galaxies ===
Kuhn demonstrated firm statistical evidence for the reality of large-scale filamentary structure in the early observed cosmic galaxy distribution. 
With Princeton colleagues, he detected and characterized the then-largest known astronomical object in the visible universe by demonstrating how modern CCD photometry analysis techniques revealed a giant galaxy extending well beyond its then-known-spatial boundary.
With Scheick, he extended the practical limits of dark-sky Extragalactic astronomy|extragalactic photometry and revealed dynamical friction wakes of fast-moving embedded in galaxy cluster diffuse light.
Kuhn showed how the puzzling large stellar velocity signatures of Dwarf spheroidal galaxies|Dwarf Spheroidal galaxies (DS) could be explained by Gravitational wave|gravity wave oscillations induced by the DS Milky Way orbit. This explanation eliminated the need for vast dark matter densities in DS. He used numerical models of this interaction to predict extended stellar dwarf spheroidal tails. He later discovered the extended extra-tidal tails of several Dwarf Galaxies that were predicted from this dynamic tide model. With Fleck, Kuhn developed a nonlinear analytic model for dynamical tidal interactions of gravitating systems. Later, with Pereira, he detected and then showed how dynamical tides could account for the alignment of galaxies within galaxy clusters.
With Potter and Parise, Kuhn presented one of the earliest demonstrations of how optical polarization observations could be used to observe faint circumstellar structure. With collaborators, he showed how absorptive polarization and an “optical pumping” mechanism in the circumstellar environments of bright stars could explain the linear polarization variation that they detected across wavelength-resolved stellar spectra lines.
=== General techniques and algorithms ===
Kuhn developed algorithms for Fourier analysis of uneven data. He also created an algorithm for calibrating electronic array data without usual “flat-field” calibration limitations. He also developed algorithms for self-consistent solar telescope polarization calibration.
=== Exolife searches ===
File:HR 8799 Orbiting Exoplanets.gif|thumb|HR 8799 Orbiting Exoplanets
Kuhn showed how the planetary warming signal of near-earthlike civilizations can be used as a technomarker of advanced civilizations. With Berdyugina, Kuhn showed how exoplanetary light curves could be used to resolve exoplanetary continents and surface structure. 
Kuhn has widely argued for the need of a dedicated and specialized ground-based telescope for exoplanet studies. He argues that the signal detection advantages of a large aperture telescope suggest that we will first find and measure exolife signals from the ground at near IR wavelengths. With good optical wavefront control the large diameter advantage of ground-based telescopes can outstrip space-based searches for exolife when low-scattered light telescopes of 25m or larger are built.
=== Scientific education and research development ===
In support of the Haleakala science advantages and DKIST on Maui, Kuhn led the effort to build the IfA’s Advanced Technology Research Laboratories there and also served as its first director for 10 years. In 2013, he co-founded the Colossus Project, a public and private group of astronomers that worked to design an exolife-hunting telescope called Colossus. In 2015, Kuhn started an optics technology company, MorphOptic, Inc., focused on the practical development of methods to shape large thin mirror surfaces using high-power lasers. He also co-founded the non-profit PLANETS Foundation for the international promotion of novel telescopes and astronomy education. The Foundation is building an unusual optical telescope, Polarized Light from Atmospheres of Nearby ExtraTerrestrial Systems (PLANETS), that will be used to study Exoatmosphere|exo-atmospheres of nearby Solar System|solar system planets. He leads a team developing the telescope ExoLife Finder (ELF), devoted to studies of nearby exoplanets.
== Boards and councils ==
Kuhn has served on the board of the International Advanced Technology Solar Telescope (ATST) Council, American Universities Research Associations (AURA), AURA Solar Observatory Council, USA Decadal Survey, Science committee in Astrophysics, National Research Council, USA, University of Hawai'i at Manoa Faculty Senate Executive Committee, University of Hawaii Professional Assembly, Colossus and PLANETS Foundations, and Big Bear Solar Observatory Visiting Committee. As of 2021, he continues as a board member of the Breakthrough Starshot|Breakthrough Foundation Starshot and Watch Committees and the US National Research Council Committee on Astronomy and Astrophysics.
== Recognition ==
Kuhn has been recognized with the Hornbeck Prize by Kalamazoo College in 1977, Shenstone Prize by Princeton University in 1980, Alfred P. Sloan Fellowship by Sloan Foundation in 1986, Phillips Distinguished Lecturer by Haverford College in 1994, the Senior Humboldt Prize for scientific achievements by the Alexander von Humboldt Foundation|German Humboldt Foundation in 2010 and the Hawaii Regents’ Medal for Research Excellence. He has won 24 NASA and National Science Foundation grants for his work on the Sun, stars, and polarimetry. 
== Personal life ==
Jeff Kuhn was married in 1976. He has a son and a daughter. He enjoys long runs and duplicate bridge.
Category:American physicists
Category:1957 births