共查询到20条相似文献，搜索用时 46 毫秒
1.
Y. R. Huang C. Fang M. D. Ding X. F. Gao Z. G. Zhu S. Y. Ying J. Hu Y. Z. Xue 《Solar physics》1995,159(1):127-135
Since 1992 the solar tower telescope of Nanjing University (118°51 E, 32°03 N) as well as its multichannel solar spectrograph, originally established in 1982, have been reconstructed and a two-channel imaging spectrograph has been operated successfully. The apertures of the coelostat and the secondary mirror are both 60 cm. The spherical objective mirror, having an aperture of 43 cm and a focal length of 2170 cm, produces a solar image of 20 cm diameter. Two auxiliary telescopes using a small fraction of the coelostat's aperture were set up for guiding and H monochromatic monitoring. A multichannel spectrograph can be operated in six wavebands simultaneously. A CCD imaging spectrograph can be used for data acquisition at H and Caii K line wavebands automatically and simultaneously. The instrument consists of two CCD cameras, an image processor (SR-151), a personal computer, and a mechanical scanning device. The principal characteristics of the instruments are described. Some observational results are presented as examples. 相似文献
2.
Photographic observations of the time development of the profile of the L line of hydrogen during flares were obtained with the NRL spectrograph on ATM. The profiles for the 15 June, 1973 and 21 January, 1974 flares reported here cover both core and wings of the line. The time sequences begin before flare maximum, and continue well into the decay phase. Careful attention has been given to photometry and absolute calibration. In the case of the 15 June, 1973 flare, data are presented both first-order corrected and uncorrected for incomplete filling of the spectrograph slit by flaring material. Correction of the 21 January, 1974 flare was not possible. We discuss core symmetry and shift, and show that our observations imply integrated flare L/H intensity ratios within a factor of two of unity for these two flares. 相似文献
3.
Matthias Tecza Niranjan Thatte Fraser Clarke Timothy Goodsall Myrto Symeonidis 《New Astronomy Reviews》2006,49(10-12):647
SWIFT is an adaptive optics assisted integral field spectrograph covering the I and z astronomical bands (0.7–1.0 μm) at a spectral resolving power R 5000. At its heart is an all-glass image slicer with high throughput based on a novel de-magnifying design allowing a compact instrument. SWIFT profits from two recent developments: (i) the improved ability of second generation adaptive optics systems to correct for atmospheric turbulence in SWIFTS’s bandpass, and (ii) the availability of CCD array detectors with high quantum efficiency at very red wavelengths. It is a dedicated integral field spectrograph, specifically built to address a range of interesting astrophysical questions. 相似文献
4.
In order to study the electron density at the scale of the most encountered structures in coronal active regions a new multichannel coronagraph associated with a photoelectric spectrograph is now used at the Pic-du-Midi Observatory. In its quasi-routine mode this instrument, which is described in this paper, works with a 30 field aperture in a parallel manner with aK-polarimeter. On each observed region it obtains maps of intensities of the
3388, 10747, and 10798 Å emission lines due to Fexiii ion. Each measurement point is associated with a quasi-simultaneous image of the emission corona structures viewed in the light of the5303 Å line of Fexiv. Three examples of observations are given and the capabilities are discussed.Measuring electron density in coronal active regions. II A multichannel photoelectric coronagraph with a photo-electric spectrograph and a reflex monitor at5303 Å.LA du CNRS No. 040285. 相似文献
5.
We present high resolution detailed observations of the class 3N two-ribbon flare of 1973, July 29 (McMath 12461), which was associated with the disappearance of a large filament (disparition brusque). This flare occurred in a diffuse bipolar magnetic region completely devoid of sunspots, and was further associated with a type IV radio burst and a soft X-ray event. Extensive H filtergraph, spectrograph and magnetograph records during the main phase of the flare suggest that downfalling and streaming material is present on both ribbons for several hours during the H emission enhancement, but only at a small number of points located both on and off the ribbons. We find a poor spatial correspondence between bright emission knots in the H ribbons and the positions of the observed downward motion. We conclude that the model of infall-impact of Hyder (1967a, b) is not consistent with our filtergraph and spectrograph observations.Presently at the University of Michigan, Ann Arbor, Michigan. 相似文献
6.
Gordon Walker Nadine Dinshaw Leslie Saddlemyer Frank Younger 《Experimental Astronomy》1992,2(6):391-398
For less than $2000 in materials we have exploited the DAO 1.8 m Cassegrain spectrograph between 430 and 800 nm for differential linear spectropolarimetry at resolutions up to 30,000 by using a beamsplitting cube as single-channel analyser. The position angle of the cube is under microprocessor control and, to counteract the highly erratic response of the spectrograph image-slicer combination to linear polarisation, we convert to circular polarisation by inserting a quarter-wave plate. The analyser has 40% throughput (c.f. 50% ideal) and we can sense polarisation levels as small as 0.01% with a CCD. Incomplete action of the quater-wave plate is probably the ultimate limit to precision. Details of the reduction procedure are given together with illustrative results for the Be star Per. 相似文献
7.
The impulsive phase of a large solar limb flare of June 20, 1989 总被引：1，自引：0，他引：1
On 1989 June 20, we observed in H the impulsive phase of a 3B/X1.6 limb flare with high temporal resolution. Line profiles have been acquired every 2.3 s with an imaging spectrograph. During the eruption of a filament we observed in H a moving plasma blob from what we believe to be a second loop which correlated spatially and temporally with a microwave source at 1.4 GHz observed by VLA. A magnetodynamic model is used to understand the development of the moving plasma blob. 相似文献
8.
Using the atomic-beam technique in absorption, a new kind of very narrow-passband filter is obtained, which may also be used as a high-resolution spectrograph and as a Babcock window for detecting solar magnetic fields without a spectrograph. 相似文献
9.
Multi-Channel Subtractive spectrograph and filament observations 总被引：1，自引：0，他引：1
A Multi-Channel Subtractive Double Pass spectrograph (MSDP) has been achieved at the Meudon solar tower. Line profiles are obtained simultaneously in a two dimensional field. Space and time resolutions are very suitable for observation of fast chromospheric phenomena.Maps have been computed for Doppler shifts and H-intensities (core and wings) in a plage including a temporary activated filament. The radial velocity is zero in the core of the filament, but it increases toward the edges with opposite signs on the both sides. Velocity loops inclined at small angles on the axis of the filament are suggested. 相似文献
10.
The present paper describes a two-dimensional multi-band spectrograph which is located at Yunnan Observatory (25° N 103° E), Kunming. The instrument consists of a coelostat system with an aperture of 40 cm, and spatial resolution better than 1 under excellent seeing, and a spectrograph equipped with a plane reflecting grating. It can simultaneously obtain spectral data in ten bands, including the Balmer lines, metallic lines [Fei
6173 ,D
1, 2, 3, Mg, and Caii (H + K)] and Heii
4686 . We are able to control the observational processes by means of a computer and obtain the following data synchronously or quasi-synchronously: multi-band spectra, H filtergrams, magnetic field, and white light. With the aid of H slit-jaw filtergrams, we can determine where and when the spectral data are obtained and, on the basis of analysing the spectral line profiles, we can understand the physical characteristics of an active region and derive the fields of physical parameters. For the line-of-sight velocities, the values measured are as high as hundreds of kilometers per second and as low as a few kilometers per second. 相似文献
11.
The recent observations of solar flares, made with a Lyot filter and a spectrograph in H, HeD3, higher Balmer lines, metallic lines, and continuum, are discussed. It is important to study the energy supply of non thermal particle/ conduction/ irradiation into the lower atmosphere from the optical observations with high temporal and spatial resolutions. Simultaneous observations from ground-based observatories and instruments on board satellites are necessary for understanding flare plasma of low and high energy. 相似文献
12.
R. Tousey J. D. F. Bartoe J. D. Bohlin G. E. Brueckner J. D. Purcell V. E. Scherrer N. R. Sheeley Jr. R. J. Schumacher M. E. Vanhoosier 《Solar physics》1973,33(2):265-280
Some of the first observations obtained with the Naval Research Laboratory's Extreme Ultraviolet Spectrograph (S082A) during the first Skylab mission are presented and compared with magnetograms and other ground-based data. The instrument is a slitless objective-type grating spectrograph covering 170–630 Å and described in Solar Phys.
27, 251 (1972). Chromospheric network, loop prominences, active regions, a flare, limb brightening, XUV bright points, and coronal holes are among the phenomena shown and discussed. 相似文献
13.
Calculations of electron temperature (T
e) and density (N
e) sensitive line ratios in Sixi involving transitions in the 358–604 wavelength range are presented. These are shown in the form of ratio-ratio diagrams, which should in principle allow bothN
e andT
e to be deduced for the Sixi line-emitting region of a plasma. However a comparison of these with observational data for two solar flares, obtained with the Naval Research Laboratory's S082A spectrograph on boardSkylab, reveals that the experimental ratios are much larger than expected from theory, which is probably due to the Sixi lines in the S082A spectra being blended with transitions from species including Nev, Fexi, and Fexii. Possible future applications of the Sixi results to spectral data from the Coronal Diagnostic Spectrometer on the Solar and Heliospheric Observatory are briefly discussed. 相似文献
14.
J.- P. Wülser 《Solar physics》1988,114(1):115-126
H line profile observations of solar flares with high temporal resolution are an important tool for the analysis of the energy transport mechanism from the site of the flare energy release to the chromosphere. A specially designed instrument (imaging spectrograph) allows two-dimensional imaging of an active region simultaneously in 15 spectral channels along the H line profile with a temporal resolution of 5.4 s. Two flares have been observed in November 1982. The first one shows H signatures which one would typically expect in the case of explosive chromospheric evaporation produced by massive injection of non-thermal electrons. The observations of the other flare indicate that the heating of the upper chromosphere is dominated by thermal conduction, although during the impulsive hard X-ray burst there are also signatures of heating by non-thermal electrons. 相似文献
15.
Howard C. McAllister 《Solar physics》1971,21(1):27-37
Six spectrograms of the solar spectrum were obtained in the region from 1970 to 1800 at a resolution of approximately 2 × 105 with a rocket-borne spectrograph using an echelle as the principal dispersing element. Reduction of data obtained has been completed in the region from 1946.5 to 1963.5 , in which 79 absorption features are measured and 33 identified. Most of the identified stronger lines are due to Fei. A significant feature of the solar spectrum in this region coincides with the raie ultime of Sei. 相似文献
16.
The synthetic Voigt profile of the following transitions (v=0,v=0), (v=0,v=1), (v=1,v=1), (v=1,v=0) have been computed for different concentrations and temperatures of CO and compaed to the measured intensities of the UV sunspot spectrum by a high resolution spectrograph. From this comparison the solar minimum temperature has been determined. 相似文献
17.
F. P. Keenan E. S. Conlon D. A. Bowden B. N. Dwivedi K. G. Widing 《Solar physics》1994,149(1):137-142
Theoretical electron-density-sensitive emission line ratios in B-like AIix are presented forR =I(385.01 )/I(392.42 ). A comparison of these with high spectral resolution solar flare data, obtained with the S082A slitless spectrograph on boardSkylab, reveals agreement between theory and observation for those spectra that were observed during the later stages of the flares. These results provide experimental support for the accuracy of the line-ratio calculations, and also resolves discrepancies found previously when the theoretical results were compared with solar observations from the S-055 instrument on boardSkylab. However, the agreement between theory and observation for a spectrum obtained during the early stages of a flare is very poor, which probably indicates that the 392.42 line is blended with a transition arising from a species formed at a very high electron temperature. 相似文献
18.
Linda J. Smith 《Astrophysics and Space Science》1994,216(1-2):291-295
High spatial and spectral resolution observations of the ring nebula surrounding the LBV candidate He 3-519 are presented. The data were obtained at the AAT with the UCL echelle spectrograph and cover the H and [N II] emission lines for two slit positions. The nebular motions are clearly resolved and have a total velocity spread of -40 to +100 km s–1. The shell shows some deviations from spherical symmetry but overall is expanding at 61 km s–1 and has an ionized mass of 2 M. The nebular parameters are found to be similar to those of the AG Car nebula, suggesting that it resulted from a bulk ejection of material 2 × 104 yr ago. 相似文献
19.
The analysis of the dynamic evolution of the chromospheric electron density during solar flares is fundamental for the testing of solar flare models. For this purpose we developed a digital imaging spectrograph for the observation of higher Balmer lines below 400 nm with a time resolution of 1 s and an algorithm for the determination of the electron density from the observed line profiles. On January 5, 1992 a M1/1N flare was observed in H, H and Caii H and the temporal evolution of the electron density was determined. The chromospheric electron density rises several times from less than 3 × 1019 to 1 × 1020 m–3 during the hard X-ray peaks. 相似文献
20.
Observations of a type III radio event and of concurrent H absorbing features are related. They were obtained with the Nançay Radioheliograph and the Multichannel Subtractive Double Pass spectrograph operating in H at Meudon. We are looking for the signature at chromosphere levels of the acceleration of the elctron beams triggering the type III bursts. Some promising results are pointed out: the relationship between velocities in H and the occurrence of the type III bursts, the shape of H line which reveals turbulent motions, the presence of parasitic magnetic polarity and the probable existence of a shock wave. A schematic scenario of the phenomenon is proposed, taking into account the observational constraints. 相似文献