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1.
The Spectro-Polarimeter for Infrared and Optical Regions (SPINOR) is a new spectro-polarimeter that will serve as a facility instrument for the Dunn Solar Telescope at the National Solar Observatory. This instrument is capable of achromatic polarimetry over a very broad range of wavelengths, from 430 to 1600 nm, allowing for the simultaneous observation of several visible and infrared spectral regions with full Stokes polarimetry. Another key feature of the design is its flexibility to observe virtually any combination of spectral lines, limited only by practical considerations (e.g., the number of detectors available, space on the optical bench, etc.). Visiting Astronomers, National Solar Observatory, operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science Foundation.  相似文献   

2.
The writer reports some recent observations carried out with the McMath Solar Telescope, which can be interpreted as due to rotational motions in prominences. Kitt Peak National Observatory Contribution No. 454. Visiting Astronomer to the Solar Division, Kitt Peak National Observatory, operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation.  相似文献   

3.
Ellerman bombs are bright emission features observed in the wings of Hα, usually in the vicinity of magnetic concentrations. Here we show that they can also be detected in the Ca II infrared triplet lines, which are easier to interpret and therefore allow for more detailed diagnostics. We present full Stokes observations of the 849.8 and 854.2 nm lines acquired with the new spectro-polarimeter SPINOR. The data show no significant linear polarization at the level of 3 × 10−4. The circular polarization profiles exhibit measureable signals with a very intricate pattern of peaks. A non-LTE analysis of the spectral profiles emerging from these features reveals the presence of strong downflows (∼10 {km s−1}) in a hot layer between the upper photosphere and the lower chromosphere. Visiting Astronomers, National Solar Observatory, operated by the Association of Universities for Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science Foundation. The National Center for Atmospheric Research (NCAR) is sponsored by the National Science Foundation, USA.  相似文献   

4.
V. Bumba 《Solar physics》1967,1(3-4):371-376
Preliminary results of magnetic field measurements in small sunspots from spectrograms obtained with the aid of the McMath Solar Telescope at the Kitt Peak National Observatory are presented. The measured intensities are greater than or equal to about 1200 Gauss. Furthermore, a broadening of the Fei line 6302.508 Å was found in some places of intergranular space. The importance of intergranular space as a possible potential earliest stage of sunspot development is mentioned.Kitt Peak National Observatory, Contribution No. 222.Visiting Astronomer, 1964, Kitt Peak National Observatory.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the Nat. Science Foundation.  相似文献   

5.
Inference of magnetic fields from very high spatial, spectral, and temporal resolution polarized images is critical in understanding the physical processes that form and evolve fine scale structures in the solar atmosphere. Studying high spectral resolution data also helps in understanding the limits of lower resolution spectral data. We compare three different methods for calibrating the line-of-sight component of the magnetic field. Each method is tested for varying degrees of spectral resolution on both synthetic line profiles computed for known magnetic fields and real data. The methods evaluated are: (a) the differences in the center of gravity of the right and left circular components for different spectral resolution, (b) conversion of circular polarization, at particular wavelengths, to magnetic fields using model-dependent numerical solutions to the equations of polarized radiative transfer, and (c) the derivative method using the weak field approximation. Each method is applied to very high spatial and spectral resolution circular polarization images of an active region, acquired in the Fei 5250 Zeeman-sensitive spectral line. The images were obtained using the 20 m pass-band tunable filter at NSO/Sacramento Peak Observatory Vacuum Tower Telescope. We find that the center-of-gravity separation offers the best way of inferring the longitudinal magnetic field.Work partially done while the author held an NRC-USAF Resarch Associateship.Supported under a USAF/AFOSR research initiative.The National Optical Astronomy Observatories are operated by the Association of Universities Research in Astronomy, Inc. (AURA), under cooperative agreement with the National Science Foundation (NSF). Partial support for National Solar Observatory is provided by the United States Air Force under a Memorandum of Understanding with NSF.  相似文献   

6.
A magnetograph is an instrument which makes measurement of solar magnetic field by measuring Zeeman induced polarization in solar spectral lines. In a typical filter based magnetograph there are three main modules namely, polarimeter, narrow-band spectrometer (filter), and imager(CCD camera). For a successful operation of magnetograph it is essential that these modules work in synchronization with each other. Here, we describe the design of instrument control system implemented for the Solar Vector Magnetograph under development at Udaipur Solar Observatory. The control software is written in Visual Basic and exploits the Component Object Model (COM) components for a fast and flexible application development. The user can interact with the instrument modules through a Graphical User Interface (GUI) and can program the sequence of magnetograph operations. The integration of Interactive Data Language (IDL) ActiveX components in the interface provides a powerful tool for online visualization, analysis and processing of images.  相似文献   

7.
Yngve Öhman 《Solar physics》1969,10(1):178-183
During a stay at the Kitt Peak National Observatory the writer has tried to find an influence of flare radiation on the high photospheric and low chromospheric lines of the area occupied by the flare. Observations have been made in the H region and in the region of the H and K lines. When flare emission is present in sunspots some of the faint (molecular) lines seem to be weakened. When a flare appears near the solar limb some of the Evershed-type (chromospheric) lines are strongly influenced.Kitt Peak National Observatory Contribution No. 481.Visiting Astronomer to the Solar Division, Kitt Peak National Observatory, operated by the Association of Universities for Research in Astronomy, Inc. under contract with the National Science Foundation.  相似文献   

8.
We describe an instrument we have built and installed at Mees Solar Observatory on Haleakala, Maui, to measure polarization in narrow-band solar images. Observations in Zeemansensitive photospheric lines have been made for nearly all solar active regions since the instrument began operations in 1992. The magnetograph includes a 28-cm aperture telescope, a polarization modulator, a tunable Fabry-Pérot filter, CCD cameras and control electronics. Stokes spectra of a photospheric line are obtained with 7 pm spectral resolution, 1 arc sec spatial resolution over a field 4.7 arc min square, and polarimetric precision of 0.1%. A complete vector magnetogram observation can be made every eight minutes. The flexibility of the instrument encourages diverse observations: besides active region magnetograms we have made, for example, composite vector magnetograms of the full solar disk, and H polarization movies of flaring regions.  相似文献   

9.
Phillips  K.J.H.  Read  P.D.  Gallagher  P.T.  Keenan  F.P.  Rudawy  P.  Rompolt  B.  Berlicki  A.  Buczylko  A.  Diego  F.  Barnsley  R.  Smartt  R.N.  Pasachoff  J.M.  Babcock  B.A. 《Solar physics》2000,193(1-2):259-271
The Solar Eclipse Coronal Imaging System (SECIS) is an instrument designed to search for short-period modulations in the solar corona seen either during a total eclipse or with a coronagraph. The CCD cameras used in SECIS have the capability of imaging the corona at a rate of up to 70 frames a second, with the intensities in each pixel digitised in 12-bit levels. The data are captured and stored on a modified PC. With suitable optics it is thus possible to search for fast changes or short-period wave motions in the corona that will have important implications for the coronal heating mechanism. The equipment has been successfully tested using the Evans Solar Facility coronagraph at National Solar Observatory/Sacramento Peak and during the 11 August 1999 eclipse at a site in north-eastern Bulgaria. The instrument is described and preliminary results are outlined.  相似文献   

10.
It is assumed that pulsar radiation originates in a polar cap region and that the emission mechanism is curvature radiation. It is further assumed the radiation reaching an observer at any one time may represent contributions from several particle bunches moving relativistically along different magnetic field lines and radiating mutually incoherently. These assumptions are used to explanation of the minimum of linear polarization appearing near the profile centre of some pulsars.The National Radio Astronomy Observatory is operated by the Associated Universities Inc., under contract with the National Science Foundation.  相似文献   

11.
Full Stokes polarimetry is obtained using the National Solar Observatory Vacuum Tower Telescope at Sacramento Peak while observing the magnetically sensitive infrared Fei line at wavelength of 1.56. A technique is described which makes use of the high magnetic resolution in this spectral range to remove instrumental polarization from observed StokesQ, U, andV line profiles.Supported under a USAF/AFOSR research initiative.Operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation.  相似文献   

12.
O. Engvold 《Solar physics》1970,11(2):183-197
Absorption band spectra of BH and BO have been searched for and not found in spectra of sunspots.Electronic oscillator strengths are available only for the A 1 -X 1 + system of the BH molecule. The absence of the (0,0) band of BH at 4332 Å reflects a solar abundance of boron logA B<2.5.The band spectra of BN are several orders of magnitude weaker in sunspots than those of BH and BO.Kitt Peak National Observatory Contribution No. 488.Visiting Astronomer, Solar Division, Kitt Peak National Observatory - Operated by The Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.  相似文献   

13.
This article describes the use of the telescope output Stokes vector measured during a polarization calibration to infer the properties of mirrors in the telescope itself. Polarization calibrations performed at the National Solar Observatory Dunn Solar Telescope are used to demonstrate this technique (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

14.
Donald F. Neidig 《Solar physics》1989,121(1-2):261-269
The basic results of white-light flare (WLF) photometric and spectrographic observations are reviewed. WLFs represent the most extreme density conditions in solar optical flares and are similar to stellar flares in many respects. It is shown that WLFs originate in the low chromosphere and upper photosphere, and that their huge radiative losses remain difficult to explain within the context of known mechanisms of energy transport.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation. Partial support for the National Solar Observatory is provided by the USAF under a Memorandum of Understanding with the NSF.  相似文献   

15.
A Stokes polarimeter has been built at the High Altitude Observatory to obtain line profiles in both linear and circular polarization in solar spectral lines. These measurements are interpreted using the theory of radiative transfer in the presence of a magnetic field to obtain vector magnetic fields on the solar disk and using the theory of resonance scattering and the Hanle effect to obtain vector magnetic fields in prominences. The polarimeter operates on the Sacramento Peak Observatory 40 cm coronagraph. It is an extensively modified and improved version of an earlier instrument.Polarization modulation is achieved by two KD*P Pockels cells at the coronagraph prime focus and demodulation is by a microprocessor. The instrument control and data handling is done by a minicomputer. Silicon photodiode 128 element line array detectors have replaced the two photomultipliers used on the earlier instrument. This gives a speed increase of a factor of 50.A polarization scrambler provides a chop to a reference beam of unpolarized light by time scrambling the polarization of the solar beam. This device improves sensitivity to polarizations less than 0.01%. The polarization measurements are photon noise limited in most cases. This noise is 0.1% for a typical three second observation which is about one gauss on the longitudinal field and 10 gauss on the transverse field.The National Center for Atmospheric Research is sponsored by The National Science Foundation.  相似文献   

16.
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17.
A program to measure long-period brightness oscillations at the solar limb has been pursued at Sacramento Peak Observatory for several years. Past improvements in observing technique and data analysis are reviewed. The encouraging results aid in the verification of the reality and the origin of oscillatory signals. However, the main stumbling block to this and other observational programs is the length of observing sequences imposed by the day/night cycle. The South Pole has received considerable attention as a site where extended observations might be possible. Currently, the Sacramento Peak program is developing a South Pole telescope designed for the observing technique and data analysis proven in Sunspot. A review of pertinent South Pole site parameters is given here for other workers who may be considering South Pole observations. Observing sequences longer than 150 hr are possible, though rare. Data sets of this duration are very attractive for solar oscillation studies.Proceedings of the 66th IAU Colloquium: Problems in Solar and Stellar Oscillations, held at the Crimean Astrophysical Observatory, U.S.S.R., 1–5 September, 1981.Operated by the Association of Universities for Research in Astronomy, Inc., under contract AST 78-17292 with the National Science Foundation.Summer Research Assistant at Sacramento Peak Observatory.  相似文献   

18.
MUSICOS (for MUlti-SIte COntinuous Spectroscopy) is an international project to facilitate and organize world-wide multi-site campaigns in high resolution spectroscopy, in view of obtaining a complete time coverage of various types of variable stellar phenomena.In the framework of this project a vast spectroscopic campaign was organized in December 1992, involving 8 sites well distributed in longitude around the Earth. The observations concerned three scientific programs, among which was the study of azimuthal structures in the wind and chromosphere of the pre-Main-Sequence Herbig Ae star AB Aur.The Hei 5876 line of AB Aur, which is formed in the expanding chromosphere of this star, in the innermost parts of its wind, was monitored at a resolution of 30000, nearly continuously for about 4 days. A spectacular variability of this line was discovered, the profile changing from pure emission to a composite profile including a deep absorption component in the course of a few hours. This variability can be the signature of azimuthal structures in the wind of AB Aur.We present the data collected during the campaign, and discuss possible interpretations of the spectacular variations of the Hei 5876 line.ESA/VILSPAUniversity of British Columbia CanadaBased on observations obtained during the MUSICOS 92 MUlti-SIte COntinuous Spectroscopic campaign from the National Solar Observatory McMath/Pierce 1.5 m, University of Hawaii 2.2 m, Beijing Observatory Xinglong 2.16 m, La Palma 4.2 m William Herschel Telescope, and Observatoire de Haute-Provence 1.52 m telescopes.Presented at the Cosmic Winds and the Heliosphere Conference in Tucson, Arizona, U.S.A., October 18–22, 1993.Visiting Astronomer, Kitt Peak National Observatory, National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.Visiting Astronomer National Solar Observatory, National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.  相似文献   

19.
We have observed 11 hydrogen and 3 helium lines in a quiescent prominence; none have been previously observed except for the He 10830 line. In contrast to Zirker's results based on longer-wavelength infrared lines, we find no net velocity shift, Doppler widths narrower than his by more than 30%, and a hydrogen excitation temperature 3 times higher. From the line intensity method, we find a helium temperature of 5300(±200) K and a hydrogen temperature of 10 900(±1900) K, in reasonable agreement with the findings of visible line studies. We conclude that helium lines are formed in the central region while hydrogen lines are formed around the edges of the prominence.Visiting Astronomer at the National Solar Observatory, a division of the National Optical Astronomy Observatories, which are operated by the Association of Universities for Research in Astronomy, under contract with the National Science Foundation.  相似文献   

20.
We present some interesting results from the mean pulse polarization observations of four southern pulsars made at the Australian National Radio Astronomy Observatory, Parkes, using the 64-m telescope in June and July, 1988. The 2 × 16 × 5 MHz filter system from Jodrell Bank has proved excellent in de-dispersing the pulse signals and measuring their polarization properties. We give the data for the four pulsars in some detail and discuss their spectral behaviour.  相似文献   

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