U.S. Naval Observatory Flagstaff Station

Abstract We present the fundamental properties of 87 stars based on angular diameter measurements from the Navy Precision Optical Interferometer, 36 of which have not been measured previously using interferometry. Our sample consists of 5 dwarfs, 3 subgiants, 69 giants, 3 bright giants, and 7 supergiants, and span a wide range of spectral classes from B to M. We combined our angular diameters with photometric and distance information from the literature to determine each star’s physical radius, effective temperature, bolometric flux, luminosity, mass, and age.

In the history of astronomy, major advances in our understanding of the Universe have come from dramatic improvements in our ability to accurately measure astronomical quantities. Aided by rapid progress in information technology, current sky surveys are changing the way we view and study the Universe. Next- generation surveys will maintain this revolutionary progress. We focus here on the most ambitious survey currently planned in the visible band, the Large Synoptic Survey Telescope (LSST). LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: constraining dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. It will be a large, wide-field ground-based system designed to obtain multiple images covering the sky that is visible from Cerro Pachon in Northern Chile. The current baseline design, with an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg2 field of view, and a 3,200 Megapixel camera, will allow about 10,000 square degrees of sky to be covered using pairs of 15-second exposures in two photometric bands every three nights on average. The system is designed to yield high image quality, as well as superb astrometric and photometric accuracy. The survey area will include 30,000 deg2 with ? < +34.5? , and will be imaged multiple times in six bands, ugrizy, covering the wavelength range 320-1050 nm. About 90% of the observing time will be devoted to a deep- wide-fast survey mode which will observe a 20,000 deg2 region about 1000 times in the six bands during the anticipated 10 years of operation. These data will result in databases including 10 billion galaxies and a similar number of stars, and will serve the majority of science programs. The remaining 10% of the observing time will be allocated to special programs such as Very Deep and Very Fast time domain surveys. We describe how the LSST science drivers led to these choices of system parameters.

URAT1 is an observational, astrometric catalog covering most of the δ −15° area and a magnitude range of about R = 3–18.5. Accurate positions (typically 10–30 mas standard error) are given for over 228 million objects at a mean epoch around 2013.5. For the over 188 million objects matched with the Two Micron All Sky Survey (2MASS) point-source catalog proper motions (typically 5–7 mas yr –1 standard errors) are provided. These data are supplemented by 2MASS and AAVSO Photometric All-Sky Survey (APASS) photometry. Observations, reductions, and catalog construction are described, together with results from external data verifications. The catalog data are served by CDS, Starsbourg (I/329).

The effect of light source spectral power distribution on the visual brightness of anthropogenic sky glow is described. Under visual adaptation levels relevant to observing the night sky, namely with dark-adapted (scotopic) vision, blue-rich (“white”) sources produce a dramatically greater sky brightness than yellow-rich sources. High correlated color temperature LEDs and metal halide sources produce a visual brightness up to 8× brighter than low-pressure sodium and 3× brighter than high-pressure sodium when matched lumen-for-lumen and observed nearby. Though the sky brightness arising from blue-rich sources decreases more strongly with distance, the visual sky glow resulting from such sources remains significantly brighter than from yellow sources out to the limits of this study at 300 km.

We develop an estimate of the complete outdoor lighting of Flagstaff Arizona, as well as lighting-use densities (lumens per acre) for a number of different land uses. We find a total outdoor light output of 173 million lumens (Mlm) including sports lighting, and 139 Mlm without sports lighting, with an uncertainty of about 7%. The average fraction escaping directly upward from light fixtures is estimated to be 8.3%. After correcting approximately for near-ground blocking described in the accompanying paper by Luginbuhl et al., total uplight is estimated at 17.9 Mlm or 12.2 Mlm with and without sports lighting, respectively. Of these 17.9 Mlm, 33% arise from sports lighting, when it is on; when sports lighting is off, commercial and industrial lighting account for 62% with the remainder dominated by residential (14%) and roadway lighting (12%). We show that the 1989 Flagstaff lighting code that limited total outdoor lighting on new construction has reduced the growth rate of lighting, resulting in a 17% growth in light escaping into the sky from 1989 to 2003, compared to a 43% increase expected if the 1989 code had not been enacted. If all legally nonconforming lighting installed before 1989 were to be brought into compliance with the code, we would expect sky glow in Flagstaff to actually decrease by 36% compared to that in 2003; if all lighting, including residential, could be converted to fully shielded fixtures, sky glow would decrease to about half the current value. The implications for the most effective ways to address sky glow through lighting codes are discussed.

Five cities in the southwest United States were selected for an analysis of the impact of outdoor lighting practices on nighttime sky glow as observed from distances of 8–67 km. Data from the Suomi National Polar-orbiting Partnership (NPP) satellite visible infrared imaging radiometer suite day/night band were used to identify light sources for input to an atmospheric sky glow model. Total lumens of outdoor lighting were estimated by matching modelled to observed anthropogenic sky luminance at ground locations. The results of two conservative treatments were then modelled for each city: all outdoor luminaires fully shielded with the current lumen amount, and fully shielded luminaires with a lumen amount scaled to 2075 lm capita −1 , matching Flagstaff, Arizona. The results indicate 42–88% reductions in average all-sky glow utilizing these ‘best practices’ for environmental conservation.

This paper reports Very Large Array observations at 325 and 1425 MHz (λ90 cm and λ20 cm) during and near the periastron passage of HD 80606b on HJD 2454424.86 (2007 November 20). We obtain flux density limits (3σ) of 1.7 mJy and 48 μJy at 325 and 1425 MHz, respectively, equivalent to planetary luminosity limits of 2.3 × 10 24 erg s −1 and 2.7 × 10 23 erg s −1 . Unfortunately, these are several orders of magnitude above the nominal Jovian value (at 40 MHz) of 2 × 10 18 erg s −1 . The motivation for these observations was that the planetary magnetospheric emission is driven by a stellar wind–planetary magnetosphere interaction so that the planetary luminosity would be elevated near periastron. We estimate that, near periastron, HD 80606b might be as much as 3000 times more luminous than Jupiter. Recent transit observations of HD 80606b provide reasonably stringent constraints on the planetary mass and radius, and, because of the planet's highly eccentric orbit, its rotation period is likely to be "pseudo-synchronized" to its orbital period, allowing a robust estimate of the former. Consequently, we are able to make relatively robust estimates of the emission frequency of the planetary magnetospheric emission and find it to be around 60–90 MHz. While this is too low for our reported observations, we compare HD 80606b to other high-eccentricity systems and assess the detection possibilities for both near-term and more distant future systems. Of the known high-eccentricity planets, only HD 80606b is likely to be detectable, as the others (HD 20782B and HD 4113) are both lower mass and longer rotational periods, which imply weaker magnetic field strengths. We find that both the forthcoming "EVLA low band" system, which will operate as low as 65 MHz, and the Low Frequency Array may be able to improve upon our planetary luminosity limits for HD 80606b, and do so at a more optimum frequency. If the low-frequency component of the Square Kilometre Array (SKA-lo) and a future lunar radio array are able to approach their thermal noise limits, they should be able to detect an HD 80606b-like planet, unless the amount by which the planet's luminosity increases is substantially less than the factor of 3000 that we estimate; for the SKA-lo, which is to be located in the southern hemisphere, future planetary surveys will have to find southern hemisphere equivalents of HD 80606b.

We present accurate photometric sequences around 20 symbiotic stars. The sequences extend over wide brightness and color ranges, and are suited to cover quiescence as well as outburst phases. The sequences are intended to assist both present time photometry as well as measurement of photographic plates from historical archives.

Determining the distance to the open cluster M29 (NGC 6913) has proven difficult, with distances determined by various authors differing by a factor of two or more. To solve this problem, we have initiated a new photometric investigation of the cluster in the Vilnius seven-color photometric system, supplementing it with available data in the BV and JHK s photometric systems and spectra of the nine brightest stars of spectral classes O and B. Photometric spectral classes and luminosities of 260 stars in a 15' × 15' area down to V = 19 mag are used to investigate the interstellar extinction run with distance and to estimate the distance of the Great Cygnus Rift, ∼ 800 pc. The interstellar reddening law in the optical and near-infrared regions is found to be close to normal, with the ratio of extinction to color excess R BV = 2.87. The extinction A V of cluster members is between 2.5 and 3.8 mag, with a mean value of 2.97 mag, or E B − V = 1.03. The average distance of eight stars of spectral types O9–B2 is 1.54 ± 0.15 kpc. Two stars from the seven brightest stars are field stars: HDE 229238 is a background B0.5 supergiant and HD 194378 is a foreground F star. In the intrinsic color–magnitude diagram, seven fainter stars of spectral classes B3–B8 are identified as possible members of the cluster. The 15 selected members of the cluster of spectral classes O9–B8 plotted on the log L / L ☉ versus log T eff diagram, together with the isochrones from the Padova database, give the age of the cluster as 5 ± 1 Myr.

Parallaxes are presented for nine Planetary Nebulae central stars.

This paper examines the evidence to support the view that the inability of seamen to determine accurate longitude at sea in sailing ships was a major factor in the loss of ships and crews that was effectively solved by the introduction of the marine chronometer. It concludes that this was not the case and that a more compelling factor for the safety of ships was the introduction of mechanical propulsion systems.

The Large Synoptic Survey Telescope (LSST) will be a large, wide-field ground-based system designed to obtain, starting in 2015, multiple images of the sky that is visible from Cerro Pachon in Northern Chile. About 90% of the observing time will be devoted to a deep-wide-fast survey mode which will observe a 20,000 deg$^2$ region about 1000 times during the anticipated 10 years of operations (distributed over six bands, $ugrizy$). Each 30-second long visit will deliver 5$\sigma$ depth for point sources of $r\sim24.5$ on average. The co-added map will be about 3 magnitudes deeper, and will include 10 billion galaxies and a similar number of stars. We discuss various measurements that will be automatically performed for these 20 billion sources, and how they can be used for classification and determination of source physical and other properties. We provide a few classification examples based on SDSS data, such as color classification of stars, color-spatial proximity search for wide-angle binary stars, orbital-color classification of asteroid families, and the recognition of main Galaxy components based on the distribution of stars in the position-metallicity-kinematics space. Guided by these examples, we anticipate that two grand classification challenges for LSST will be 1) rapid and robust classification of sources detected in difference images, and 2) {\it simultaneous} treatment of diverse astrometric and photometric time series measurements for an unprecedentedly large number of objects.

Various laboratory experiments have demonstrated the efficacy of cooling emulsions for exposures at low light levels.1'2'3 Such experiments have been used for the general investigation of reciprocity failure at low intensity levels.4'5 Cooling is an effective means of increasing the sensitivity of emulsions for astronomical exposures. In this paper, results are presented in support of a preliminary report given at the June 1960 meetings of the Astronomical Society of the Pacific.6

Abstract Using a wavelength-generalized version of the Garstang (1991) model, we evaluate overhead sky glow as a function of distance up to 300 km, from a variety of lamp types, including common gas discharge lamps and several types of LED lamps. We conclude for both professional, and especially cultural (visual), astronomy, that low-pressure sodium and narrow-spectrum amber LED lamps cause much less sky glow than all broad-spectrum sources.

Abstract We present the results of eight-color CCD photometry of 674 stars in the direction of the open cluster Tombaugh 5 in Camelopardalis. The stars are observed in the Vilnius system supplemented by the broad-band I filter; the field is of 22’ diameter, the limiting magnitude is V =17.7 mag. The catalog contains the coordinates, V magnitudes, seven color indices, two-dimensional spectral types determined from photometric parameters, interstellar extinctions and distances. The color-magnitude diagram plotted for 480 individually dereddened stars is used to identify cluster members and to determine the distance (1.74 kpc) and age (200-250 Myr) of the cluster. The faintest cluster stars classified are of spectral class G0. The cluster contains two blue stragglers of spectral classes B2-B4, both of them seem to be visual binaries. The extinction A

The preservation of mirror surface quality and figure are of paramount importance at the Navy Prototype Optical Interferometer. There are on the order of 108 eight-inch optical flats mounted in the interferometer's optical train, 102 of which are permanently mounted inside the 9000 cubic foot vacuum feed system. The flats are specified for manufacture at λ/20 peak-to-valley surface variation (λ = 633 nm) over a 7.2 inch clear aperture. Silver coating with a dielectric overcoat is subsequently applied to the reflecting surface. The objective when mounting the mirror is to preserve the surface quality and figure of the coated flats as much as possible. Surface deflections occur due to pressure points inherent in the mount. The mount consists of a modified commercially available tangent-arm gimbaled-type structure. In order to minimize the mounting effects and allow for a wider thermal operational range, modifications were made to the primary mirror cell in the following areas: edge support region, front face tabs, rear face loaders, and diameter. In this paper we describe the detailed cell modifications, a finite element analysis (FEA) of the mounted flat, the free-standing and as-mounted surface figure of a typical eight-inch diameter flat as measured with a phase-shifting interferometer, the resulting mount-induced deflections, a comparison between the measured and FEA model, and conclusions.

Abstract Magnitudes and color indices in the Vilnius seven-color system were determined for 1752 stars down to V = 19.5 mag in the direction of the open cluster M29 (NGC 6913). The region is centered at RA = 20:24, DEC = +38:30 (J2000) and covers an area of 1.5 sq. deg. The photometric data are used to classify about 70% of stars in spectral and luminosity classes and peculiarity types.

Deep optical (UBVI) searches (to V∼24) of the smallest GRB localizations available from the Third Interplanetary Network and two possibly associated optical transients (OT) have been carried out at the USNOFS 1.0-m and CTIO 1.5-m telescopes. For the high-latitude (b=−26°) OT localization, we find a blue source with broad-band colors consistent with a QSO/AGN, which is consistent with our earlier work that found a QSO likely associated with OT050510. For the low-latitude OT (b=−1°), we find a red star of about spectral class M. We are unable to provide evidence about whether these historical OT events are related to the nearby but much later GRB events.

Abstract The accuracy of new CCD photometry in the Vilnius system of the M67 cluster is analyzed. The observational material is obtained during six observing runs in 1994-2001 with the 1 meter telescope of the USNO Flagstaff Station. The main task was to establish CCD standards of high accuracy and to eliminate large-scale errors from our CCD photometry. We compare our results with the published CCD photometric data in other photometric systems. The comparison reveals considerable systematic errors in some datasets.

Abstract The accuracy with which infrared photometry can be carried out is currently limited by poor definition of the instrumental system and by the accuracy of the available standard stars. We present new colour transformations between the CIT J, H, K photometric system and systems currently in use at Cerro Tololo, Mauna Kea and Kitt Peak. The precision of the J, H, K data for some of the stars observed by Elias et al. is improved and the system extended to fainter stars suitable for use with larger telescopes and/or infrared arrays. Evidence of infrared variability has been detected for one M dwarf star in our programme.