
Jennifer L. BartlettCenter for Astrophysics | Harvard & Smithsonian
Jennifer L. Bartlett
PhD Astronomy
Editor-in-chief, 𝘉𝘪𝘰𝘨𝘳𝘢𝘱𝘩𝘪𝘤𝘢𝘭 𝘌𝘯𝘤𝘺𝘤𝘭𝘰𝘱𝘦𝘥𝘪𝘢 𝘰𝘧 𝘈𝘴𝘵𝘳𝘰𝘯𝘰𝘮𝘦𝘳𝘴
About
65
Publications
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Introduction
Because I am fortunate to study astronomy, I share what I am learning by developing practical applications, teaching, and public outreach. As a graduate student, I taught introductory astronomy at the University of Virginia and Hampden-Sydney College. I now develop software for almanac production, celestial navigation, and illuminance predictions. While my dissertation focused on the Solar Neighborhood census, my current research involves understanding how light passes through our atmosphere.
Additional affiliations
October 2010 - August 2021

Position
- Chief Software Products Division
Description
- Developing astronomical software for almanac and related computation: Naval Observatory Vector Astrometry Software (NOVAS), Multi-year Interactive Computer Almanac (MICA), System To Estimate Latitude and Longitude Astronomically (STELLA), Solar-Lunar Almanac Core (SLAC), and associated websites with online calculators. Supporting traditional celestial navigation. Researching illuminance and refraction.
August 2006 - June 2007
Education
August 1997 - January 2007
Publications
Publications (65)
Astronomy's extensive collections of photographic glass plates contain historical images and spectra of celestial objects, documenting more than a century of the observable cosmos. Many reveal changes, both sudden (explosive), periodic, or gradual (evolutionary), which is material of immense interest for time-domain studies because of the long time...
For most locations on the Earth, the Sun appears to rise and set daily, a reassuring, regular pattern often taken for granted. Assuming a reliable, high-accuracy astrometric algorithm, the differences between observed and computed sunrise times should be attributable to refraction, dip, or terrain. Between 2017 June to 2021 September, Urban careful...
The International Glass Plates Group is a recently formed gathering that includes astronomers, librarians, historians, curators and others with representation from a host of countries. What has brought us together is our assumed curatorship of collections of astronomical photographic plates and associated records that were once open resources in ou...
Even in the land of the midnight Sun, the Sun rises and sets. In September and October 2019, the U.S. Naval Observatory (USNO) deployed a prototype refractometer and spectroradiometer on the USCGC HEALY while she was engaged in Arctic operations. The first instrument records the Sun when it is visible at low elevations while the second monitors ava...
We argue that it is essential that the Astro2020 survey of the present state of American astronomy and the recommendations for the next decade address the issue of ensuring preservation of, and making more discoverable and accessible, the field's rich legacy materials. These include both archived observations of scientific value and items of histor...
Gaia is currently revolutionizing modern astronomy. However, much of the Galactic plane, center and the spiral arm regions are obscured by interstellar extinction, rendering them inaccessible because Gaia is an optical instrument. An all-sky near infrared (NIR) space observatory operating in the optical NIR, separated in time from the original Gaia...
Over the past decades and even centuries, the astronomical community has accumulated a signif-icant heritage of recorded observations of a great many astronomical objects. Those records con-tain irreplaceable information about long-term evolutionary and non-evolutionary changes in our Universe, and their preservation and digitization is vital. Unfo...
Preliminary analyses of eight brown dwarfs observed by the U.S. Naval Observatory infrared parallax program show no clear indication of astrometric perturbations due to low mass companions. The data were collected using ASTROCAM on the 1.55-m (61-in) Kaj Strand Astrometric Reflector from 2000 September through 2006 June over periods from 5.0 to 5.3...
The USNO is responsible for providing information through its website on various types of natural phenomena, including times of sunrise and sunset for any given day and location. Alternative websites were explored to see what options are available in case the USNO can no longer support this on-line tool in the future. Websites with sunrise/sunset c...
As a step toward completing and characterizing the census of the solar neighborhood, we present astrometric, photometric, and spectroscopic observations of 32 systems observed with the Cerro Tololo Inter-American Observatory 0.9 m and 1.5 m telescopes. Astrometry from the 0.9 m indicates that among the 17 systems that had no previous published trig...
We present trigonometric, photometric, and photographic distances to 1748
southern ($\delta \leq$0$^\circ$) M dwarf systems with $\mu \ge$ 0\farcs18
yr$^{-1}$, of which 1404 are believed to lie within 25 parsecs of the Sun. The
stars have 6.67 $\leq$ $V_J$ $\leq$ 21.38 and 3.50 $\leq$ ($V_J-K_s$) $\leq$
9.27, covering the entire M dwarf spectral se...
Preliminary analyses of ten brown dwarfs observed by the U.S. Naval Observatory infrared parallax program show no clear indication of astrometric perturbations due to low mass companions. The data were collected using ASTROCAM on the 1.55-m (61-in) Kaj Strand Astrometric Reflector from 2000 September through 2006 June over periods from 2.0 to 5.3 y...
Barnard’s Star remains popular with planet hunters because it is
not only an extremely near, high proper motion star, but also the object
of early planet-detection claims. In 1963, van de Kamp explained
perturbations in its proper motion by the presence of a planet. In 1969,
he produced another single-planet solution and a two-planet solution to
th...
Current models that predict the times of sunrise and sunset are only
accurate, typically, to a few minutes. Variations in atmospheric
refraction contribute to the differences between computed and observed
times. At high latitudes, slight changes in refraction can cause the Sun
to remain continuously above the horizon instead of appearing to set. A...
LP 876-10 is a nearby active M4 dwarf in Aquarius at a distance of 7.6 pc.
The star is a new addition to the 10-pc census, with a parallax measured via
the Research Consortium on Nearby Stars (RECONS) astrometric survey on the
Small & Moderate Aperture Research Telescope System's (SMARTS) 0.9-m telescope.
We demonstrate that the astrometry, radial...
Preliminary analyses of ten brown dwarfs observed by the U.S. Naval Observatory infrared parallax program show no clear indication of astrometric perturbations due to low mass companions. The data were collected using ASTROCAM on the 1.55-m Strand Astrometric Reflector from 2000 October through 2006 June over periods from 1.3 to 5.4 years. After ou...
On 21 August 2017, “…as the last ray of sunlight vanishes, a
scene of unexampled beauty, grandeur, and impressiveness…”
(Newcomb 1890) will break upon fortunate observers along a narrow band,
approximately 73 mi (118 km) wide, that crosses twelve states from
Oregon to South Carolina. In response to growing interest in the first
total solar eclipse...
The AAS and AIP co-hosted a Workshop in April 2012 with NSF support
(AST-1110231) that recommends establishing a Working Group on Time
Domain Astronomy (WGTDA) to encourage and advise on preserving
historical observations in a form meaningful for future scientific
analysis. Participants specifically considered archival observations
that could descr...
Of the seven transits of Venus for which unambiguous observations exist,
four have occurred since the U.S. Naval Observatory (USNO) was
established in 1844. With the Transit of Venus Commission, the USNO was
heavily involved in observing the December 8, 1874, and December 6,
1882, events to establish an accurate value for the astronomical unit.
In...
The fourth United States Naval Observatory (USNO) CCD Astrograph Catalog,
UCAC4 was released in August 2012 (double-sided DVD and CDS data center Vizier
catalog I/322). It is the final release in this series and contains over 113
million objects; over 105 million of them with proper motions. UCAC4 is an
updated version of UCAC3 with about the same...
The Naval Observatory Vector Astrometry Software (NOVAS) is a source-code library that provides common astrometric quantities and transformations to high precision. The library can supply, in one or two subroutine or function calls, the instantaneous celestial position of any star or planet in a variety of coordinate systems. NOVAS also provides ac...
UCAC4 is a compiled, all-sky star catalog covering mainly the 8 to 16
magnitude range in a single bandpass between V and R. Positional errors
are about 15 to 20 mas for stars in the 10 to 14 mag range. Proper
motions have been derived for most of the about 113 million stars
utilizing about 140 other star catalogs with significant epoch
difference t...
Preliminary analyses of ten brown dwarfs observed by the U.S. Naval Observatory infrared parallax program show no indication of astrometric perturbations due to low mass companions. The data were collected using ASTROCAM on the 1.55-m Strand Astrometric Reflector from 2000 September through 2006 June over periods from 2.0 to 5.8 years. After our st...
Preliminary analyses of ten brown dwarfs observed by the U.S. Naval Observatory infrared parallax program show no indication of astrometric perturbations due to low mass companions. The data were collected using ASTROCAM on the 1.55-m Strand Astrometric Reflector from 2000 September through 2006 April over periods from 3.0 to 5.4 years. After our s...
On August 21, 2017, most of the United States will experience a partial
solar eclipse with a total solar eclipse visible from a narrow band,
approximately 73 mi (118 km) wide, crossing twelve states. The Shawnee
National Forest, Illinois falls within this favored region but Austin,
Texas does not. While both locations lie along the April 8, 2024, p...
The Naval Observatory Vector Astrometry Software (NOVAS) is a source-code library that provides common astrometric quantities and transformations. NOVAS calculations are accurate at the sub-milliarcsecond level. The library can supply, in one or two subroutine or function calls, the instantaneous celestial position of any star or planet in a variet...
Before addressing queries about how and what to preserve among astronomical devices, the question of what constitutes a historic instrument must be considered. Certainly, the lenses are the defining feature of a Clark refractor. Since 1867, when Newcomb inquired about the possibility of obtaining a great glass from Alvan Clark & Sons, the U.S. Nava...
In rapid succession, two chances to experience a total solar eclipse will soon occur over the middle of the United States. Usually, a total solar eclipse is, at most, a once in a lifetime event. However, the celebrated shadows will race over the Shawnee National Forest, near Makanda, Illinois, twice in less than 7 years. The centerlines of the 2017...
Despite the continuing importance of ground-based parallax measurements, few active programs remain. Because new members of the solar neighborhood tend towards later spectral types, infrared parallax programs are particularly desirable. Therefore, the astrometric quality of the new infrared camera, FanCam, developed by the Virginia Astronomical Ins...
We present a collection of short lecture-tutorial (or homework) activities, designed to be both quantitative and accessible to the introductory astronomy student. Each of these involves interpreting some real data, solving a problem using ratios and proportionalities, and making a conclusion based on the calculation. Selected titles include: "The M...
Trigonometric parallax is the only direct means of measuring stellar distances but is only effective within a limited distance. For stars too distant for the determination of accurate parallaxes, indirect methods, such as standard candles, are used. RR Lyrae and Cepheid variable stars are used as standard candles, because their luminosities can be...
It was a dark and rainy morning, not far out of Shanghai, when we saw the 2009 July 22 total solar eclipse. Many of the Americans puttering around their equipment that morning, in hopes that the sky would clear enough to catch some of event they had traveled around the world to view, were already planning ahead for 2017 August 21, when a narrow str...
Although ground-based parallax measurements remain an essential means of
determining stellar distances, hardly any programs currently operate. Of
the 3,125 northern-hemisphere stellar systems expected within 25 pc,
only 1,131 systems are known (K. Slatten 2009, pc). Measurements at
infrared wavelengths would be especially helpful in identifying sol...
The Naval Observatory Vector Astrometry Software (NOVAS) is a source-code library in Fortran and C that provides common astrometric quantities and transformations. NOVAS calculations are accurate at the sub-milliarcsecond level. It can supply, in one or two subroutine or function calls, the instantaneous celestial position of any star or planet in...
J-MAPS is a small, funded, space-based, all-sky visible wavelength
astrometric and photometric survey mission for 0th through 14th V-band
magnitude stars with a 2012 launch. The primary objective of the J-MAPS
mission is the generation of an astrometric star catalog with better
than 1 milliarcsecond positional accuracy and photometry to the 1
perce...
Thirteen nearby stars from the former University of Virginia Southern Parallax Program were tested for possible astrometric perturbations that might indicate very low mass companions. For 12 of these stars—LHS 34, and 3418—no clear indication of any unseen companion was detected. One star, LHS 288, however, may have a perturbation meriting further...
Barnard's Star should have significant secular acceleration because it lies close to the Sun and has the highest known proper motion along with a large radial velocity. It will pass within about 1.4 pc in another 9,750 years. Secular changes in proper motion and radial velocity are essentially the Coriolis and centrifugal accelerations, respectivel...
We present the first set of definitive trigonometric parallaxes and proper motions from the Cerro Tololo Inter-American Observatory Parallax Investigation. Full astrometric reductions for the program are discussed, including methods of reference star selection, differential color refraction corrections, and conversion of relative to absolute parall...
Thesis (Ph. D.)--University of Virginia, 2007. Includes bibliographical references.
A sample of 13 stars from the University of Virginia southern hemisphere parallax program has been tested for possible astrometric perturbations due to low-mass companions. The selected objects are primarily early to mid-M dwarfs with large parallaxes, all are within 25 parsecs, that are not known to be binaries. The data were collected from CCD pa...
Trigonometric parallaxes, proper motions, and V J (RI) KC photometry are presented for 31 stars targeted by the Cerro Tololo Inter-American Observatory Parallax Investigation (CTIOPI), a program of wide scope aimed at discovering and characterizing nearby stars. The data given are the first that have been obtained with the CTIO 1.5 m telescope, tar...
A sample of stars from the University of Virginia southern hemisphere
parallax program has been tested for possible astrometric perturbations
due to low-mass companions. The data were taken from CCD parallax
observations with the one-meter reflector at the Siding Spring
Observatory, Coonabarabran, Australia. Following our standard central
overlap s...
Barnard's Star is of particular interest due to its high proper motion, nearness to the Solar System, and previous claims of planetary companions. Based upon observations made at the Sproul Observatory between 1916 and 1962, Peter van de Kamp claimed the star had a 24-year period and a planetary companion of about 1.6 Jupiter masses (Van de Kamp, A...
At Hampden-Sydney College, we teach a one-semester introductory astronomy class targeting non-science majors. This course fulfills the laboratory science requirement, and as such the class is obligated to teach transferable skills such as basic numeracy, quantitative reasoning and data analysis. To this end, we explicitly teach the use of the most...
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