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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

An atlas of upper tropospheric radiances observed in the 6 to 7-micrometer water vapor band using TOVS data from the NOAA weather satellites during 1979-1991

This document is a pictorial atlas of the Earth's radiance emitted in the 6 to 7 micro-m water vapor band. At these wavelengths, the infrared brightness temperature corresponds to the layer-average temperature of the top few millimeters of water vapor in the atmosphere. At low altitudes, bright regions are dry slots in the upper troposphere. The satellite observations were obtained from NOAA's cloud and angle corrected measurements made by a series of polar orbiting TOVS (TIROS Operational Vertical Sounder) instruments flown from 1979 to 1991. TOVS 6.7 micro-m and 7.2 micro-m channels were converted to a single brightness temperature that simulates a high altitude channel near '6.5' micro-m. For climatological studies, the daily '6.5' micro-m overpass data were gridded to a cartesian projection with 5 by 5 degree horizontal resolution between 40 degrees N and 40 degrees S latitude. This atlas presents greyscale images of the '6.5' micro-m brightness fields for every day in every month for 13 years. The mean brightness for each of the 12 months for 13 years is presented to display interannual variability, and the annual cycle of 12 monthly means is summarized on a single page. Statistical summaries are presented from other investigations in progress.

Chesters, Dennis↗
NASA NTRS1992

An X-ray catalog and atlas of galaxies

An X-ray catalog and atlas of galaxies observed with the Einstein Observatory imaging instruments (IPC and HRI) are presented. The catalog comprises 493 galaxies, including targets of pointed observations, and RSA or RC2 galaxies serendipitously included in Einstein fields. A total of 450 of these galaxies were imaged well within the instrumental fields, resulting in 238 detections and 2123 sigma upper limits. The other galaxies were either at the edge of the visible field of view or confused with other X-ray sources. For these a rough measure of their X-ray emission is also given. The atlas shows X-ray contour maps of detected galaxies superposed on optical photographs and gives azimuthally averaged surface brightness profiles of galaxies detected with a high signal-to-noise ratio.

Fabbiano, G.↗
NASA NTRS1993

Spectral classification with the International Ultraviolet Explorer: An atlas of B-type spectra

New criteria for the spectral classification of B stars in the ultraviolet show that photospheric absorption lines in the 1200-1900A wavelength region can be used to classify the spectra of B-type dwarfs, subgiants, and giants on a 2-D system consistent with the optical MK system. This atlas illustrates a large number of such spectra at the scale used for classification. These spectra provide a dense matrix of standard stars, and also show the effects of rapid stellar rotation and stellar winds on the spectra and their classification. The observational material consists of high-dispersion spectra from the International Ultraviolet Explorer archives, resampled to a resolution of 0.25 A, uniformly normalized, and plotted at 10 A/cm. The atlas should be useful for the classification of other IUE high-dispersion spectra, especially for stars that have not been observed in the optical.

Rountree, Janet↗
NASA NTRS1992

The ATLAS-1 Shuttle mission

The Atmospheric Laboratory for Applications and Science (ATLAS-1) encompasses instruments which will be useful in determining long-term solar variability as well as in forging links to the measurements obtained by other spacecraft for the perturbed middle and upper atmosphere. The simultaneous measurements that will be conducted by ATLAS-1 of stratospheric concentrations of ozone, chlorine monoxide and water vapor, at relatively high latitudes during the northern spring, will be especially timely.

Torr, Marsha R.↗
NASA NTRS1992

Optical design for the ATLAS multispectral scanner

The Airborne Terrestrial Applications Sensor (ATLAS) system is a 15-channel imager for remote sensing applications currently under development at the NASA Stennis Space Center. This paper describes the optical design of the scan head optics, which include the linescan mirror, Dall-Kirkham telescope, collimator, and three spectrometers. The sensor package has a 7.5-inch entrance aperture with a 2.0 mrad ifov, total field of view of 73 degrees, and scan rates adjustable in the range 6-50 rev/sec. The three spectrometers have a modular design for future applications growth. Design and specifications for the telescope, special dichroics, gratings, imaging lenses, and other components for the spectrometers are described. Detector arrays for the three spectrometers, and built-in sources for radiometric calibration, will also be discussed. Finally, results of overall ATLAS systems performance analysis on optical throughput, SNR and NETD are presented.

Damommio, T.↗
NASA NTRS1993

CIV experiments on ATLAS-1

A test of the Critical Ionization Velocity (CIV) theory was made with neutral xenon releases from the Space Experiments with Particle Accelerators hollow cathode plasma contactor onboard the Shuttle Orbiter Atlantis during the ATLAS-1 mission. The gas velocity perpendicular to the Earth's magnetic field was essentially the orbital velocity (7.5 km/s), and thus it exceeded the CIV for xenon. The releases were observed with onboard instrumentation. A factor of 60 enhancement was seen in the Langmuir probe current. Calculations confirmed that release conditions generally satisfied criteria for CIV and predicted a maximum factor of 20 increase in plasma density. Thus, CIV effects were likely to have occurred during the ATLAS-I experiments.

Marshall, J. A.↗
NASA NTRS1992

Develop research plan for use of atlas data

This contract study is devoted to performing atmospheric photochemical modeling research in conjunction with the ATLAS missions. The purpose of the work was to provide scientific understanding of the stratospheric chemical measurements performed by the suite of ATLAS instruments. Photochemical model studies of the stratosphere were performed. SAGE and Dobson Umkehr ozone measurements were studied.

Newchurch, Michael↗
NASA NTRS1994

IRAS sky survey atlas: Explanatory supplement

This Explanatory Supplement accompanies the IRAS Sky Survey Atlas (ISSA) and the ISSA Reject Set. The first ISSA release in 1991 covers completely the high ecliptic latitude sky, absolute value of beta is greater than 50 deg, with some coverage down to the absolute value of beta approx. equal to 40 deg. The second ISSA release in 1992 covers ecliptic latitudes of 50 deg greater than the absolute value of beta greater than 20 deg, with some coverage down to the absolute value of beta approx. equal to 13 deg. The remaining fields covering latitudes within 20 deg of the ecliptic plane are of reduced quality compared to the rest of the ISSA fields and therefore are released as a separate IPAC product, the ISSA Reject Set. The reduced quality is due to contamination by zodiacal emission residuals. Special care should be taken when using the ISSA Reject images. In addition to information on the ISSA images, some information is provided in this Explanatory Supplement on the IRAS Zodiacal History File (ZOHF), Version 3.0, which was described in the December 1988 release memo. The data described in this Supplement are available at the National Space Science Data Center (NSSDC) at the Goddard Space Flight Center. The interested reader is referred to the NSSDC for access to the IRAS Sky Survey Atlas (ISSA).

Wheelock, S. L.↗
NASA NTRS1994

An atlas of southern MK standards from 5800 to 10200 A

An atlas of stellar spectra covering the wavelength range from 5800 to 10,200 A is presented of 126 southern MK standard stars, covering the luminosity classes I, III, and V. Some peculiar stars are included for comparison purposes. The spectra were obtained at a resolution of 4.3 A per pixel using a Cassegrain-mounted Boller and Chivens spectrograph equipped with a Reticon detector. The quality and utility of the data are discussed and examples of the spectra are presented. The atlas is available in digital format through the NSSDC.

Danks, Anthony C.↗
NASA NTRS1994

The ATLAS-1 mission

Atmospheric Laboratory for Applications and Science (ATLAS)-1 was launched on March 24, 1992, carrying an international payload of 14 investigations, and conducted a successful series of experiments and observations over the subsequent 9 days. The objectives included: measuring the solar irradiance at high precision; remote sensing of the composition of the stratosphere, mesosphere, and thermosphere using techniques for wavelengths from 300 A to 5 mm; and inducing auroras by means of 1.2 amp electron beams. A subset of these instruments will subsequently be flown in a series of shuttle missions at roughly 1-year intervals over an 11-year solar cycle. The frequent recalibration opportunities afforded by such a program allows the transfer of calibrations to longer duration orbiting observatories. The ATLAS-1 mission occurred at the same time as the Upper Atmosphere Research Satellite (UARS), TIROS-N, and ERB satellites were in operation, and correlative measurements were conducted with these. In all, the mission was most successful in achieving its objectives and a unique and important database was acquired, with many scientific firsts accomplished. This paper provides the mission overview for the series of papers that follow.

Torr, Marsha R.↗
NASA NTRS1994

An atlas of Doppler emission-line tomography of cataclysmic variable stars

Doppler emission-line tomography is a technique similar to medical tomography. In this atlas the emission-line profiles of cataclysmic variable stars, seen at different orbital phases, are transformed into velocity space images. This transformation makes many of the complex line profile changes easier to interpret. The emission contributions of the disk and the s-wave are clearly separated in these images, and any emission from the stream and the secondary star can often be identified. In this atlas, Doppler tomograms of Hbeta, He I lambda 4471, and He II lambda 4686 emission lines of 18 cataclysmic variable stars are presented. The Doppler images provide insights into the individual systems and a better technique for measuring and radial velocity amplitude of the white dwarf.

Kaitchuck, Ronald H.↗
NASA NTRS1995

Thermospheric nitric oxide from the ATLAS 1 and Spacelab 1 missions

Spectral and spatial images obtained with the Imaging Spectrometric Observatory on the ATLAS 1 and Spacelab 1 missions are used to study the ultraviolet emissions of nitric oxide in the thermosphere. By synthetically fitting the measured NO gamma bands, intensities are derived as a function of altitude and latitude. We find that the NO concentrations inferred from the ATLAS 1 measurements are higher than predicted by our thermospheric airglow model and tend to lie to the high side of a number of earlier measurements. By comparison with synthetic spectral fits, the shape of the NO gamma bands is used to derive temperature as a function of altitude. Using the simultaneous spectral and spatial imaging capability of the instrument, we present the first simultaneously acquired altitude images of NO gamma band temperature and intensity in the thermosphere. The lower thermospheric temperature images show structure as a function of altitude. The spatial imaging technique appears to be a viable means of obtaining temperatures in the middle and lower thermosphere, provided that good information is also obtained at the higher altitudes, as the contribution of the overlying, hotter NO is nonnegligible. By fitting both self-absorbed and nonabsorbed bands of the NO gamma system, we show that the self absorption effects are observable up to 200 km, although small above 150 km. The spectral resolution of the instrument (1.6 A) allows separation of the N(+)(S-5) doublet, and we show the contribution of this feature to the combination of the NO gamma (1, 0) band and the N(+)(S-5) doublet as a function of altitude (less than 10% below 200 km). Spectral images including the NO delta bands support previous findings that the fluorescence efficiency is much higher than that determined from laboratory measurements. The Spacelab 1 data indicate the presence of a significant population of hot NO in the vehicle environment of that early shuttle mission.

Torr, Marsha R.↗
NASA NTRS1996

The ATLAS Series of Shuttle Missions

The ATLAS space shuttle missions were conducted in March 1992, April 1993, and November 1994. The ATLAS payload and companion instruments made measurements of solar irradiance and middle atmospheric temperatures and trace gas concentrations. The solar irradiance measurements included total and spectrally resolved solar irradiance. The atmospheric measurements included microwave, infrared, and ultraviolet limb sounding, nadir ultraviolet backscatter, and solar occultation techniques. This paper introduces a special section in this issue of Geophysical Research Letters.

Kaye, Jack A.↗
NASA NTRS1996

The ATLAS Series of Shuttle Missions

The ATLAS space shuttle missions were conducted in March 1992, April 1993, and November 1994. The ATLAS payload and companion instruments made measurements of solar irradiance and middle atmospheric temperatures and trace gas concentrations. The solar irradiance measurements included total and spectrally resolved solar irradiance. The atmospheric measurements included microwave, infrared, and ultraviolet limb sounding, nadir ultraviolet backscatter, and solar occultation techniques.

Kaye, Jack A.↗
NASA NTRS1996

Observations of the Solar Irradiance in the 200-350 nm Interval During the ATLAS-1 Mission: A Comparison Among Three Sets of Measurements-SSBUV, SOLSPEC and SUSIM

The SOLSPEC, SSBUV, and SUSIM spectrometers simultaneously observed the solar spectral irradiance during the ATLAS-1 mission flown on board the Space Shuttle Atlantis in March 1992. The three instruments use different methods and means of absolute calibration and were each calibrated preflight and postflight. The three data sets are reported from 200 to 350 nm at 1.1 nm resolution. The method of comparing the three independent data sets is discussed. The importance of a common, precise wavelength scale is shown when comparing the data in wavelength regions of strong Fraunhofer lines. The agreement among the solar irradiance measurements is better than plus or minus 5%. The fact that the calibrations of the three instruments were based on three independent standards provides confidence that the absolute solar spectral irradiance in the range 200-350 nm is now known with an accuracy better than plus or minus 5%. The mean ATLAS-I solar spectrum is compared with simultaneous solar observations from the UARS SOLSTICE and UARS SUSIM instruments. The two mean solar spectra agree to within plus or minus 3%.

Cebula, R. P.↗
NASA NTRS1999

A Complete UV Atlas of Standard Stars

This program is an Astrophysics Data Program (ADP) contract, together with a follow-on contract (S- 57791 -Z), intended to produce a comprehensive ultraviolet spectral atlas of stars based on the data in the IUE Final Archive. The data in the Final Archive were uniformly processed by the NEWSIPS pipeline system. The NEWSIPS gives an improved signal-to-noise ratio for the data that will be especially beneficial to low signal portions of the spectra; and it also gives more accurate fluxes for stars by adopting the latest absolute calibration and measured instrument parameters. Therefore, this atlas provides more uniform and accurate data than the version previously published.

Wu, Chi-Chao↗
NASA NTRS2000

A Complete UV Atlas of Standard Stars

The general objective of this project is to provide a comprehensive ultraviolet spectral atlas of stars based on the data in the IUE Final Archive. The data have been uniformly processed by the IUE NEWSIPS pipeline system. The NEWSIPS gives an improved signal to noise ratio for the data that will be especially beneficial to low signal portions of the spectra; and it also gives more accurate fluxes for stars by adopting the latest absolute calibration and measured instrument parameters. Our new atlas, therefore, provides more uniform and accurate data than the version previously published. In addition, considerable efforts were devoted to obtain reliable spectral types, V,B-V, and E(B-V). Our goal is to provide the information which can be used with reasonable confidence by scientists.

Wu, Chi-Chao↗