A Discussion on solar studies with special reference to space observations - Observations of the extreme ultraviolet solar spectrum

1971 ◽  
Vol 270 (1202) ◽  
pp. 59-70 ◽  
Keyword(s):  
Special Reference ◽  
Present State ◽  
Extreme Ultraviolet ◽  
Solar Spectrum ◽  
Ultraviolet Spectrum ◽  
Future Work ◽  
Space Observations

The present state of knowledge of the Sun’s extreme ultraviolet spectrum is reviewed, and areas for future work are indicated. Recent extreme ultraviolet spectroheliograms, including one that shows an importance 2N flare, are discussed.

A Discussion on solar studies with special reference to space observations - Interpretation of extreme ultraviolet emissions from the Sun

1971 ◽  
Vol 270 (1202) ◽  
pp. 71-75 ◽  
Keyword(s):  
Special Reference ◽  
Observational Data ◽  
Extreme Ultraviolet ◽  
Active Regions ◽  
The Sun ◽  
Quiet Sun ◽  
Flux Measurements ◽  
Ultraviolet Emissions ◽  
Descriptive Models ◽  
Space Observations

The purpose of this review is to consider the analysis of extreme u.v. space observations for the interpretation of the Quiet Sun (Q.), active regions (a.r.) and flares (fl.). The three components must be segregated from one another using the observational data that exists. We cannot count on having every type of observation for every occasion. It becomes necessary to make some simple assumptions concerning the components Q, a.r. and fl. in order that they can be measured consistently. I give below some descriptive models which are complete enough to represent the complex varying Sun at all times but simple enough to be expressed quantitatively in a few numbers. The aim will be to interpret all extreme u.v. observations on the basis of these models and to regard them as the norm. Exceptional phenomena would be regarded as variations from the models. Ideally all intensity and flux measurements would be made within individual spectrum lines or in continua at specified wavelengths. However, many valuable observations are based on broad spectral regions and it is necessary to devise methods for interpreting them.

scholarly journals Ultraviolet Albedo of Comet West (1976 VI)

1980 ◽  
Vol 90 ◽  
pp. 263-266
Author(s):  
P. D. Feldman
Keyword(s):  
Solar Radiation ◽  
Solar Spectrum ◽  
Ultraviolet Spectrum ◽  
The Moon ◽  
Lunar Dust ◽  
Cometary Dust ◽  
A Value ◽  
Dust Coma ◽  
Spectrometer Slit ◽  
The Continuum

The ultraviolet spectrum of Comet West (1976 VI) in the range 1200-3200 Å was recorded by rocket-borne instruments on March 5.5, 1976. At the time of launch, r = 0.385, Δ = 0.84 and the phase angle was 78°. Longward of 2100 Å the continuum of solar radiation scattered by cometary dust is detected and is found to closely follow the solar spectrum. Since the dust coma is completely included in the spectrometer slit, the ultraviolet albedo can be determined relative to the visible and this ratio is found to be ≈0.3 at 2700 Å. There is evidence for a further decrease in albedo near 2200 Å. Using a visible albedo of 0.2 gives a value of 0.06 for the cometary albedo at 2700 Å, a value similar to that found for the moon and lunar dust in this spectral region.

Extreme-Ultraviolet Spectrum of N iv*

1971 ◽  
Vol 61 (5) ◽  
pp. 625 ◽  
Author(s):  
D. J. Michels ◽  
S. G. Tileord ◽  
J. W. Quinn
Keyword(s):  
Extreme Ultraviolet ◽  
Ultraviolet Spectrum

scholarly journals A new solar spectrum in the extreme ultraviolet.

1959 ◽  
Vol 64 ◽  
pp. 133
Author(s):  
R. R. Tousey ◽  
J. D. Purcell ◽  
D. M. Packer ◽  
W. R. Hunter
Keyword(s):  
Extreme Ultraviolet ◽  
Solar Spectrum

GOES High cadence Operational Total Irradiance: planned data products

2021 ◽  
Author(s):  
Martin Snow ◽  
Stephane Beland ◽  
Odele Coddington ◽  
Steven Penton ◽  
Don Woodraska
Keyword(s):  
Extreme Ultraviolet ◽  
Solar Spectrum ◽  
Total Solar Irradiance ◽  
The Other ◽  
Spectral Irradiance ◽  
First Year ◽  
X Ray ◽  
Solar Spectral Irradiance ◽  
Total Irradiance ◽  
High Cadence

<p>The GOES-R series of satellites includes a redesigned instrument for solar spectral irradiance: the Extreme ultraviolet and X-ray Irradiance Sensor (EXIS).  Our team will be using a high-cadence broadband visible light diode to construct a proxy for Total Solar Irradiance (TSI).  This will have two advantages over the existing TSI measurements:  measurements are taken at 4 Hz, so the cadence of our TSI proxy is likely faster than any existing applications, and the observations are taken from geostationary orbit, so the time series of measurements is virtually uninterrupted.  Calibration of the diode measurements will still rely on the standard TSI composites.  </p><p>The other measurement from EXIS that will be used is the Magnesium II core-to-wing ratio.  The MgII index is a proxy for chromospheric activity, and is measured by EXIS every 3 seconds.  The combination of the two proxies can be used to generate a model of the full solar spectrum similar to the NRLSSI2 empirical model.</p><p>We are in the first year of a three-year grant to develop the TSI proxy and the SSI model, so only very preliminary findings will be discussed in this presentation.</p>

scholarly journals ALEXIS Lunar Observations

1996 ◽  
Vol 152 ◽  
pp. 465-470
Author(s):  
B.C. Edwards ◽  
J.J. Bloch ◽  
D. Roussel-Dupré ◽  
T.E. Pfafman ◽  
Sean Ryan
Keyword(s):  
Solar Radiation ◽  
Extreme Ultraviolet ◽  
Solar Spectrum ◽  
Lunar Orbit ◽  
The Moon ◽  
Small Satellite ◽  
Large Area ◽  
Lunar Observations ◽  
Night Sky

The ALEXIS small satellite was designed as a large area monitor operating at extreme ultraviolet wavelengths (130 − 190 Å). At these energies, the moon is the brightest object in the night sky and was the first source identified in the ALEXIS data. Due to the design of ALEXIS and the lunar orbit, the moon is observed for two weeks of every month. Since lunar emissions in the extreme ultraviolet are primarily reflected solar radiation these observations may be useful as a solar monitor in the extreme ultraviolet. The data show distinct temporal and spectral variations indicating similar changes in the solar spectrum. We will present a preliminary dataset of lunar observations and discussions covering the variations observed and how they relate to the solar spectrum.

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