A5050671913- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Impact of Light on Environment and Health
- SAS software applications and methods
- History and Developments in Astronomy
- Astrophysical Phenomena and Observations
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Infrared Target Detection Methodologies
- Calibration and Measurement Techniques
- Atmospheric Ozone and Climate
- Pulsars and Gravitational Waves Research
- CCD and CMOS Imaging Sensors
- Remote Sensing in Agriculture
- Atmospheric and Environmental Gas Dynamics
- Urban Transport and Accessibility
- Advanced Semiconductor Detectors and Materials
- Urban Heat Island Mitigation
- Astrophysics and Cosmic Phenomena
- Circadian rhythm and melatonin
- Galaxies: Formation, Evolution, Phenomena
- Retinal Imaging and Analysis
Flagstaff Medical Center
2022
United States Naval Observatory
2004-2018
United States Department of the Navy
1996-2013
United States Navy
1996-2013
Universities Space Research Association
2004
Rice University
1996
USNO-B is an all-sky catalog that presents positions, proper motions, magnitudes in various optical passbands, and star/galaxy estimators for 1,042,618,261 objects derived from 3,643,201,733 separate observations. The data were obtained scans of 7435 Schmidt plates taken the sky surveys during last 50 years. USNO-B1.0 believed to provide coverage, completeness down V = 21, 02 astrometric accuracy at J2000, 0.3 mag photometric up five colors, 85% distinguishing stars nonstellar objects. A...
Trigonometric parallax determinations are presented for 28 late type dwarfs and brown dwarfs, including eight M with spectral types between M7 M9.5, 17 L L0 L8, three T dwarfs. Broadband photometry at CCD wavelengths (VRIz) and/or near-IR (JHK) these objects 24 additional late-type Supplemented astrometry from the literature, ten two parallaxes established by association bright, usually HIPPARCOS primaries, this material forms basis studying various color-color color-absolute magnitude...
We present new JHK photometry on the MKO-NIR system and spectroscopy for a large sample of L T dwarfs. Photometry has been obtained 71 dwarfs, 56. The comprises newly identified very red objects from Sloan Digital Sky Survey (SDSS) known dwarfs SDSS Two Micron All (2MASS). Spectral classification carried out using four previously defined indices Geballe et al. that measure strengths near infrared water methane bands. identify nine L8–9.5 14 SDSS, including latest yet found by T7 dwarf...
We present preliminary trigonometric parallaxes and proper motions for 22 L dwarfs 18 T measured using the ASTROCAM infrared imager on US Naval Observatory (USNO) 1.55 m Strand Astrometric Reflector. The results presented here are based observations obtained between 2000 September 2002 November; about half of objects have an observational time baseline Δt = 1.3 yr 2.0 yr. Despite these short baselines, astrometric quality is sufficient to produce significant new results, especially nearer...
We have compiled L' and M' photometry of 63 single binary M, L,and T dwarfs obtained at UKIRT using the MKO filter set. This compilation includes new data for 8 L 13 7 dwarfs, 5 Gl 229A. compute L_bol, BC_K, T_eff 42 whose flux-calibrated JHK spectra, photometry, trigonometric parallaxes are available, we estimate these quantities 9 other spectra been obtained. BC_K is a well-behaved function near-IR spectral type with dispersion ~0.1 mag types M6-T5; it significantly more scattered T5-T9....
The U.S. Naval Observatory CCD trigonometric parallax program is described in detail, including the instrumentation employed, observing procedures followed, and reduction applied. Astrometric results are presented for 72 stars ranging apparent brightness from V = 15.16 to 19.58. Photometry all 426 individual reference employed astrometric solutions. Seventeen of 23 with V(tau) greater than 200 km/s form a well-delineated sequence extreme subdwarfs covering M(V) between 11.5 14.5 vs - I...
Abstract Human activity is rapidly increasing the negative impact of artificial skyglow at even most remote professional observatory sites. Assessment actual requires an understanding propagation as a function source spectral energy distribution. The higher blue content light-emitting diodes being widely used replacement for sodium discharge lamps has greater closer to source, and less more distant mountain-top All-sky cameras with moderate angular resolution provide data metrics sufficient...
The effect of light source spectral power distribution on the visual brightness anthropogenic sky glow is described. Under adaptation levels relevant to observing night sky, namely with dark-adapted (scotopic) vision, blue-rich ("white") sources produce a dramatically greater than yellow-rich sources. High correlated color temperature LEDs and metal halide up 8× brighter low-pressure sodium 3× high-pressure when matched lumen-for-lumen observed nearby. Though arising from decreases more...
We develop an estimate of the complete outdoor lighting Flagstaff Arizona, as well lighting-use densities (lumens per acre) for a number different land uses. find total light output 173 million lumens (Mlm) including sports lighting, and 139 Mlm without with uncertainty about 7%. The average fraction escaping directly upward from fixtures is estimated to be 8.3%. After correcting approximately near-ground blocking described in accompanying paper by Luginbuhl et al., uplight at 17.9 or 12.2...
We present panoramic sky brightness measures in the Johnson V band made at US Naval Observatory Flagstaff Station. find that these show much less glow from than expected using total light output and unshielded fraction determined recently by Luginbuhl et al. Garstang's 1991 modeling approach. suggest difference arises principally diminution of upward-directed after emission fixtures reflection ground due to interaction with structures vegetation. This not only reduces effective albedo, it...
We present a simplified method using geographic analysis tools to predict the average artificial luminance over hemisphere of night sky, expressed as ratio natural condition. The VIIRS Day/Night Band upward radiance data from Suomi NPP orbiting satellite was used for input model. is based upon relation between sky glow brightness and distance observer source radiance. This relationship developed Garstang radiative transfer model with input, then refined calibrated ground-based all-sky V-band...
Deep I-band imaging to I approximately 26.5 of the soft gamma-ray repeater SGR 1900+14 region has revealed a compact cluster massive stars located only few arcseconds from fading radio source thought be location (SGR). This was previously hidden in glare pair M5 supergiant (whose light removed by point-spread function subtraction) proposed Vrba et al. as likely associated with 1900+14. The at least 13 members within radius 0.6 pc based on an estimated distance 12-15 kpc. It is remarkably...
Trigonometric parallaxes of 16 nearby planetary nebulae are presented, including reduced errors for seven objects with previous initial results and six new objects. The median error in the parallax is 0.42 mas, twelve have less than 20 percent. PHL932 found here to be smaller was measured by Hipparcos, this peculiar object discussed. Comparisons made other distance estimates. distances determined from these tend intermediate between some short estimates long estimates; they somewhat...
We describe a system for rapidly measuring the brightness of night sky using mosaic CCD images obtained with low‐cost automated system. The portable produces millions independent photometric measurements covering entire sky, enabling detailed characterization natural conditions and light domes produced by cities. are calibrated standard stars contained within raw data, producing results closely tracking Johnson V astronomical standard. National Park Service has collected hundreds data sets...
We present observations of 2MASSI J1835379+325954, a previously unrecognized late-type M dwarf within 6 pc the Sun. Identified based analysis Two Micron All Sky Survey optical spectroscopy and photometry indicate spectral type M8.5. The star has proper motion 0759 yr-1 is clearly visible on both POSS I II photographic plate material, but it may have escaped detection in previous surveys through its proximity to Galactic plane. discuss potential implications for completeness local stellar census.
We present photometric and spectroscopic observations of SN 2000ch, an unusual extremely luminous variable star located in the galaxy NGC 3432. The object was discovered on 2000 May 3.2 during course Lick Observatory Supernova Search, at unfiltered magnitude about 17.4. Prediscovery images obtained 1997, 1998, April show with R = 19.2–19.5 mag. Optical spectra beginning 6 a smooth, flat continuum strong, broad hydrogen Balmer emission lines wavelengths consistent cataloged redshift 3432,...
We present the first parallax and luminosity measurements for an L subdwarf, sdL7 2MASS J05325346+8246465. Observations conducted over three years by USNO infrared astrometry program yield astrometric distance of 26.7+/-1.2 pc a proper motion 2.6241+/-0.0018"/yr. Combined with broadband spectral photometric measurements, we determine log(Lbol/Lsun) = -4.24+/-0.06 Teff 1730+/-90 K (the latter assuming age 5-10 Gyr), comparable to mid-type field dwarfs. Comparison J05325346+8246465 theoretical...
The rapid growth of light pollution threatens the future astronomical observation. Detailed modeling how from ground propagates through atmosphere suggests ways to limit damage.
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This paper presents new trigonometric parallaxes and proper motions for 214 stars. The measurements were made at the US Naval Observatory Flagstaff Station between 1989 2017, average uncertainty in parallax values is 0.6 mas. We find good agreement with Gaia Data Release 2 stars common, although there may be a small systematic offset similar to what has been found by other investigators. sample matched catalogs literature create photometric data set that spans ultraviolet mid-infrared. New...
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We report the results of a deep near-infrared survey with Very Large Telescope/Infrared Spectrometer and Array Camera environment supernova remnant N49 in Magellanic Cloud, which contains soft gamma repeater SGR 0526-66. Two four confirmed SGRs are potentially associated compact stellar clusters. thus searched for similar association 0526-66 imaged young cluster at projected distance ~30 pc from SGR. This constitutes third cluster-SGR link lends support to scenarios progenitors originate...
Optical polarization measurements are reported for a sample of stars viewed through the periphery two dense molecular clouds, Barnard 335 and Lynds 723. These observations suggest that direction magnetic field threading these clouds lies along position angle 111 + or - 4 deg B335 90 8 L723. In each case, deduced is approximately parallel to defined by collimated bipolar outflow driven highly obscured FIR source. R, I, H-alpha CCD images regions reveal knots optical emission apparently...
Abstract New, updated, and/or revised CCD parallaxes determined with the Strand Astrometric Reflector at Naval Observatory Flagstaff Station are presented. Included results for 309 late-type dwarf and subdwarf stars observed over 30+ years that program operated. For 124 of stars, parallax determinations from other investigators have already appeared in literature we compare different results. Also included here new or updated VI photometry on Johnson–Kron-Cousins system all but a few...
The Flagstaff Astrometric Scanning Transit Telescope (FASTT) is a fully automated telescope that takes about 41,000 CCD frames of data year for various research projects. All aspects the telescope's operation have been (e.g., target selection, observing, reduction data, and collation results), manpower needs are now under one person per year, mostly involved with routine maintenance dissemination data. This paper describes FASTT instrumental system, methods used its operation, Among...