ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Other Sources  (8)
Collection
Source
Keywords
Years
  • 1
    facet.materialart.
    Unknown
    A Program of Photometric Measurements of Solar Irradiance Fluctuations from Ground-based Observations (1990)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Photometric observations of the sun have been carried out at the San Fernando Observatory since early 1985. Since 1986, observations have been obtained at two wavelengths in order to separately measure the contributions of sunspots and bright facular to solar irradiance variations. Researchers believe that the contributions of sunspots can be measured to an accuracy of about plus or minus 30 ppm. The effect of faculae is much less certain, with uncertainties in the range of plus or minus 300 ppm. The larger uncertainty for faculae reflects both the greater difficulty in measuring the facular area, due to their lower contrast compared to sunspots, and the greater uncertainty in their contrast variation with viewing angle on the solar disk. Recent results from two separate photometric telescopes will be compared with bolometric observations from the active cavity radiometer irradiance monitor (ACRIM) that was on board the Solar Max satellite.
    Keywords: SOLAR PHYSICS
    Type: NASA, Goddard Space Flight Center, Climate Impact of Solar Variability; p 16-20
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unknown
    R associations. VI - The reddening law in dust clouds and the nature of early-type emission stars in nebulosity from a study of five associations (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Positions, identification charts, UBVRIKLMN photometry and spectral types are given for stars, illuminating reflection nebulae that are visible on the POSS prints, which have been identified in five associations. With a ratio of total to selective extinction of 4.2, the reddening law applicable to the dust clouds in which the stars are embedded is steeper than normal. The five associations exhibit 18 early-type stars with circumstellar shells, of which those with spectral types earlier than B5 characteristically have weak IR excesses, in contrast to the strong excesses indicative of circumstellar dust, of later-type stars. Color-magnitude charts show a distribution lying above the ZAMS by up to about 2 mag for both the circumstellar shell stars and those classified as rapid rotators. It is suggested that (1) rapid rotation accounts for the scatter in the color-magnitude diagram, and (2) many of the nebulous early-type emission-line stars are rapid rotators rather than pre-main sequence objects.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; Jan. 198
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unknown
    Two-dimensional Photometry of Active Regions (1984)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A set of two dimensional photometric images of solar active regions (AR's) are described. Preliminary analysis of the data is described, and estimates are presented of the contribution of an AR to total solar irradiance variations during its 1982 August 3 to 16 disk passage. Results indicate an excess contribution near the limb and a deficit away from the limb. Also apparent is an evolutionary change in the AR which is represented as a decrease in sunspot area.
    Keywords: SOLAR PHYSICS
    Type: NASA, Washington Solar Irradiance Variations on Active Region Time Scales; p 91-96
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Interpretation of surface features of Europa obtained from occultations by Io (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: Light curves of occultations of Europa by Io have been used to generate a crude map of albedo features on Europa. The best values currently available for the impact parameters and magnitude ratios for each event have been imposed on our model. Residuals between the observed and computed light curves are interpreted as albedo features on Europa. In order to improve the fit between the observations and the model, it became necessary to impose a general polar brightening. The effects of additional albedo features and alternate models are discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 26; Sept
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unknown
    Surface properties and effective resolution from ground-based observations of Mercury (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: A detailed study to evaluate ground-based photographs of Mercury has been carried out. Models of the surface scattering properties have been assumed and smeared with a Gaussian function for direct comparison with center-to-limb scans along Mercury's intensity equator. Data from a range of phase angles from 31 to 92 deg have been compared with smeared models assuming a Lambert surface, a surface which obeys the Lommel-Seeliger law and one which is Minnaertian, having a variable coefficient. Within the limits of the observations a lunar Minnaert surface yields the most consistent interpretation. An objective evaluation of the resolution of the photographs is obtained in terms of Gaussian half-widths.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 25; Aug. 197
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unknown
    Interpretation of surface features of Europa obtained from occultations by Io (1975)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Light curves of occultations of Europa by Io were used to generate a crude map of albedo features on Europa. Impact parameters and magnitude ratios for each event were imposed on a model. Residuals between the observed and computed light curves were interpreted as albedo features on Europa. In order to improve the fit between the observations and the model a general polar brightening was employed. The effects of additional albedo features and alternate models are discussed.
    Keywords: ASTRONOMY
    Type: NASA-CR-143273 , TN-74-46-REV
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unknown
    Photometric measurements of solar irradiance variations due to sunspots (1989)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: A photometric telescope constructed to obtain photometric sunspot areas and deficits on a daily basis is described. Data from this Cartesian full disk telescope (CFDT) are analyzed with attention given to the period between June 4 and June 17, 1985 because of the availability of overlapping sunspot area and irradiance deficit data from high-resolution digital spectroheliograms made with the San Fernando Observatory 28 cm vacuum solar telescope and spectroheliograph. The CFDT sunspot deficits suggest a substantial irradiance contribution from faculae and active region plage.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 343; 547-553
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unknown
    Precise ground-based solar photometry and variations of total irradiance (1992)
    In:  Other Sources
    Details
    Publication Date: 2019-08-14
    Description: Several empirical models of sunspot and facular irradiance effects were tested by assessing the degree of correlation between variations in the total solar irradiance, as measured by the active cavity radiometer irradiance monitor on the SMM and the measures of magnetic activity on the solar disk. This was done by analyzing images made during 21 days between June 20 and July 14, 1988. The paper also describes the instruments and the methods used to gather the ground-based photometric images, as well as the analysis procedure.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 97; A6 J
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...