Observational capabilities of the new medium- and low-resolution spectrograph at the 1.6-m telescope of the Sayan Observatory

The capabilities of the new medium- and low-resolution spectrograph installed recently on the 1.6-m AZT-33IK telescope at the Sayan Observatory of the Institute of Solar–Terrestrial Physics to solve the problems of ground-based optical support for the future all-skyX-ray survey of the SRGobservatory are discussed. Results of the test observations of galaxy clusters, active galactic nuclei (AGNs) and quasars, and cataclysmic variables performed immediately after the installation of the spectrograph on the telescope are presented. The results of these observations show that the AZT-33IK telescope equipped with the new medium- and low-resolution spectrograph can provide a substantial fraction of the necessary optical observations in the program of ground-based optical support for the all-sky survey of the SRG observatory.     

Affordable échelle spectroscopy with a 60 cm telescope

A new fiber‐fed spectrograph was installed at the 60 cm telescope of the Stará Lesná Observatory. The article presents tests of its performance (spectral resolution, signal‐to‐noise ratio, radial‐velocity stability) and reports observations of selected variable stars and exoplanet host stars. First test observations show that the spectrograph is an ideal tool to observe bright eclipsing and spectroscopic binaries but also symbiotic and nova‐like stars. The radial‐velocity stability (60–80 m s^–1) is sufficient to study spectroscopic binaries and to detect easily the orbital motion of hot‐Jupiter extrasolar planets around bright stars. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Initial Results of the Ichon Solar Radio Spectrograph

A new solar radio spectrograph to observe solar radio bursts has been installed at the Ichon branch of the Radio Research Laboratory, Ministry of Information and Communication, Korea. The spectrograph consists of three different antennas to sweep a wide band of frequencies in the range of 30 MHz ∼ 2500 MHz. Its daily operation is fully automated and typical examples of solar radio bursts have been successfully observed. In this paper we describe briefly its hardware and data processing methods. Then we present coronal shock speeds estimated for 34 type II bursts from May 1998 to November 2000 and compare them with those from other observatories. We also present the close relationship between onset time of type II bursts and X-ray flares as well as their associations with coronal mass ejections.     

Spectrophotometric observations of the nuclei of the seyfert galaxies NGC 4051, NGC 7469, and NGC 1275

A digital television complex, equipped with an original slitless spectrograph with transpaarent diffraction gratings, and operating on the 0.5-meter telescope of the Crimean Astrophysical Observatory, was used for spectrophotometric observations of the nuclei of Seyfert galaxies. The absolute energy distributions in the spectra of the nuclei of the Seyfert galaxies NGC 4501, NGC 7469, and NGC 1275 in the wavelength range 4000–7000 Å were obtained. Synthetic stellar magnitudes in the V band were calculated. The apparatus can be used to investigate the spectral variability of emission from the nuclei of Seyfert galaxies on a time scale of tens of minutes or more.Translated from Astrofizika, Vol. 39, No. 1, pp. 101–110, January–March, 1996.     

FLECHAS – A new échelle spectrograph at the University Observatory Jena

The new échelle spectrograph FLECHAS (Fibre Linked ECHelle Astronomical Spectrograph) is in operation at the Nasmyth‐focus of the 0.9 m telescope of the University Observatory Jena. FLECHAS is equipped with a sensitive back‐illuminated and midband coated CCD‐detector, as well as with a calibration unit for flatfield and wavelength‐calibration. The spectrograph covers the spectral range between about 3900 and 8100 Å and exhibits a resolving power of R ∼ 9300. In this article all technical characteristics of FLECHAS are described and examples of the first astronomical observations obtained with the new instrument in July 2013 at the University Observatory Jena are presented, among them the first light spectra taken with FLECHAS, simultaneous imaging and spectroscopic observations, the determination of the detection limit of the instrument, the spectroscopy of stars of different spectral types and of faint extended objects, as well as the Li‐line detection in the spectra of young solar‐like stars. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Two types of extremely short lasting decimetric bursts and their possible relation to processes in solar magnetic traps

High resolution spectral observations between 500 MHz and 550 MHz on 1972 October 25, revealed an emission event of special interest. The main feature was bursts with a single frequency duration of about 0.09 s and with a bandwidth of the same order of magnitude as the band covered by the spectrograph. The bursts occurred in showers' which lasted for one or two minutes and which were separated by quiet intervals of roughly the same length. Frequently the activity assumed a periodic nature. Periods between 0.1 s and 0.3 s were found. The most remarkable feature of the records was a very large number of bursts with the same duration as the wide band bursts, but showing a bandwidth of a mere 1–2 MHz.The wide band bursts may be plasma waves excited by proton streams trapped in coronal magnetic fields and the narrow band bursts may possibly be explained as perpendicular electrostatic electron cyclotron waves.     

Some spectroscopic observations of visual binaries

The use of a coudé spectrograph for securing the high-resolution spectrograms necessary to follow the slow variations of radial velocity exhibited by visual binaries is discussed. Recent observations, using the spectrograph at the coudé focus of the Dominion Astrophysical Observatory's 48-in. reflector, are then presented for the systems ofα UMa,ɛ Hya,β LMi andγ Leo.     

FIASCO: A new spectrograph at the University Observatory Jena

A new spectrograph (FIASCO) is in operation at the 0.9 m telescope of the University Observatory Jena. This article describes the characterization of the instrument and reports its first astronomical observations, among those lithium (6708 Å) detection in the atmosphere of young stars, and the simultaneous photometric and spectroscopic monitoring of variable stars (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Large-scale variability in the profiles of Hα and Hβ in the spectrum of the Herbig B8e star MWC 419 and a model interpretation of it

Spectroscopic data taken with a moderate resolution spectrograph in the region of the Hα and Hβ lines are presented for the Herbig B8e star MWC 419. The spectroscopic observations were accompanied by broad band BVR photometric measurements. The observations reveal a variability in the line profiles that is typical of Herbig Ae/Be stars with signs of a strong stellar wind. The greatest changes are observed in the region of the absorption components of the line profiles, which convert the profile from a type P CygII to P CygIII, as well as in the intensities of the central emission components. A model technique is used for quantitative interpretation of this variability and it shows that the P Cyg profile conversion of the absorption component can be explained in terms of a stellar wind model in which its distribution over latitude varies on a time scale of a few days. __________ Translated from Astrofizika, Vol. 50, No. 2, pp. 259–280 (May 2007).     

An EUV imaging spectrograph for high-resolution observations of the solar corona

An extreme ultraviolet (EUV) imaging spectrograph for the wavelength range from 235 to 450 Å has been developed and used for high resolution observations of the Sun. The instrument incorporates a glancing incidence Wolter Type II Telescope and a near-normal incidence toroidal grating spectrograph to achieve near-stigmatic performance over this spectral range. The design of the spectrograph entrance aperture enables both stigmatic spectra with spectral resolution adequate to observe emission line profiles and spectroheliograms of restricted portions of the Sun to be obtained concurrently. In this paper we describe the design and performance of the instrument and provide an overview of results obtained during a sounding rocket flight on May 5, 1989.     

A new high-speed solar spectrograph for meter and decameter wavelengths

A new high-speed digital solar radio spectrograph has been designed and is being operated at the Clark Lake Radio Observatory in California. The spectrograph design attempts to optimize sensitivity, dynamic range, and frequency-time resolution while utilizing modern high-speed computer data-handling techniques. The system is described and initial data observations are presented.     

Slitless spectrograph for small telescopes: First results

A slitless UBVR spectrograph has been built for use on small telescopes. Test observations on the Zeiss-600 telescope at the Terskol peak demonstrated that the spectrograph is an efficient instrument for studying high-speed processes in variable stars with a high temporal resolution. The spectrograph resolving power R ≈ 100 in the vicinity of λ = 480 nm and the error in the determination of the wavelength is approximately 3 nm. The spectrograph provides a moderate signal-to-noise ratio for stars up to 16 ^m . It permits one to measure equivalent widths of unblended lines down to 0.1 nm. The developed special software based on the theory of quantum statistics makes it possible to detect relative variations in the spectrum of approximately 10^?5–10^?6 of the bolometric flux of the star. Observations with the spectrograph made it possible to detect variations of emissions in Balmer lines and Ca II H, K lines in the EV Lac flare star in the subsecond range. The spectroscopic monitoring permits one to study stellar flares with small amplitude, to carry out a comprehensive colorimetric analysis of flare plasma, and to determine temperatures and sizes of flares in the light intensity maximum. Observations of the transit of the HAT-P-1 B exoplanet demonstrate that the chromospheric activity power of the parent star does not vary during the transit. The slitless spectrograph with a low resolving capacity opens new prospects in studying active processes occurring on stars’ surfaces.     

Physical properties of the quiescent prominence of 5 June 1996, from Hα observations

The Multichannel Subtractive Double Pass spectrograph (MSDP) is designed to observe line profiles in a 2D field of view with a good spatial and temporal resolution. In order to deal with this unique opportunity, we introduce a new method for fitting the hydrogen H line formed in prominences and deriving various plasma parameters from line profile observations. A quiescent prominence was observed on 5 June 1996, at the Pic du Midi during an international campaign between 09:30 UT and 11:00 UT with the MSDP spectrograph operating in H at the Turret Dome. Using the new fitting method, we show that the temperature, column density of hydrogen atoms and microturbulent velocity of the prominence are respectively about 8500 K, 1.4×1012 cm–2, and 10 to 20 km s–1. The electron density of the prominence is about 1.8×1010 cm–3.     

Observations of Mercury's exosphere: Spatial distributions and variations of its Na component during August 8, 9 and 10, 2003

Following the observations of August 2002 [Barbieri, C., Verani, S., Cremonese, G., Sprague, A., Mendillo, M., Cosentino, R., Hunten, D., 2004. Planet. Space Sci. 52, 1169-1175], the high resolution spectrograph of the 3.5-m Galileo National Telescope (TNG) has been used to obtain several spatially resolved spectra of Mercury's Na-D on the evenings of 8, 9 and 10 August 2003. The resolution of the spectrograph was 115,000, the slit dimensions were ^0.4″×^27″. With respect to Paper I, the planet was in a fairly similar orbital configuration, being at a geocentric distance of approximately 1 AU, and having a True Anomaly Angle (TAA) from 163°-168° instead of 171°-174°. We present here a significantly larger set of observations and discuss several important features regarding the formation of Mercury's sodium exosphere, in particular the role of photon stimulated and thermal desorptions, as well as of the solar wind sputtering and micro-meteoroid vaporization. Thanks to the very good seeing of these observations, we also report and discuss the origins and variations of equatorial structures in Mercury's early morning sodium exosphere.     

X‐shooter,a unique VLT project

X‐shooter, an intermediate resolution spectrograph, is the first VLT instrument of the second generation. It was built in a record time of 6 years by a Consortium of Institutes in Denmark, France, Italy, The Netherlands and at ESO and started operation in 2009. For the first time in astronomical instrumentation, X‐shooter offers parallel coverage from the atmospheric cut‐off at 300 nm to the K band, a feature that allows for the timely capture of the spectra of targets of unknown redshift like the GRBs (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Review of optical observations of solar flares

The recent observations of solar flares, made with a Lyot filter and a spectrograph in Hα, 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.

     

The Subaru Telescope High Dispersion Spectrograph (HDS)

The High Dispersion Spectrograph (HDS) is the échelle spectrograph for an open‐use instrument of the Subaru Telescope. The current status of the instrument is reviewed. The new image slicers that significantly improve the efficiency of observations with very high resolving power have been installed in the past three years. Brief overview of recent science results is given on studies of early generations of stars and extra‐solar planets. An upgrade plan and future prospects of this instrument are discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Infrared Imaging Solar Spectrograph At Purple Mountain Observatory

Since 1986, we have made some improvements to the multichannel solar spectrograph at Purple Mountain Observatory (PMO) step by step, and now we have developed and added to it a multichannel infrared imaging solar spectrograph. The original spectrograph can be used to observe simultaneously solar activity at 9 wave bands including Caii H and K line, Mgi b line, Hei D3 line and H through H. The newly developed infrared imaging spectrograph can work in three wavelengths, i.e., Hei 10830 Å, Caii 8542 Å, and H. We replaced plates in the original system with CCDs and placed an image reducer before each CCD in order to match the CCD pixel size. The dispersions for Hei 10830 Å, Caii 8542 Å, and H of the new imaging solar spectrograph are 0.0693 Å, 0.0767 Å, and 0.0754 Å per CCD pixel respectively, and each vertical CCD pixel represents 0.34 arc sec of solar disk. We can obtain the line-center and off-band intensities of the three lines and the intensities of continua adjacent to these lines through the new instrument. We can also acquire velocity maps and line profiles. Therefore, it is specially suitable for two-dimensional (2D) spectroscopic observations of solar flares and active regions. We carry out scanning observation by rotating the second mirror of the coelostat system. In this paper, we introduce the improvements we made and the new imaging solar spectrograph. Some observation results are also presented in this article.     

The Lyot-coronagraph with 53 cm objective

The new Lyot-coronagraph with 53 cm objective is described. The coronagraph has a grating spectrograph. The solar disk image on the slit of the spectrograph is 12.6 cm. The dispersion is 1 Å/mm in the second order. The coronagraph is situated at the Kislovodsk Station of Pulkovo Observatory, 2050 m above sea level.     

First disk-resolved spectroscopy of (4) Vesta

Vesta, the second largest Main-Belt Asteroid, will be the first to be explored in 2011 by NASA’s Dawn mission. It is a dry, likely differentiated body with spectrum suggesting that is has been resurfaced by basaltic lava flows, not too different from the lunar maria.Here we present the first disk-resolved spectroscopic observations of an asteroid from the ground. We observed (4) Vesta with the ESO-VLT adaptive optics equipped integral-field near-infrared spectrograph SINFONI, as part of its science verification campaign. The highest spatial resolution of ∼90 km on Vesta’s surface was obtained during excellent seeing conditions (0.5^″) in October 2004.We observe spectral variations across Vesta’ surface that can be interpreted as variations of either the pyroxene composition, or the effect of surface aging. We compare Vesta’s 2 μm absorption band to that of howardite-eucrite-diogenite (HED) meteorites that are thought to originate from Vesta, and establish particular links between specific regions and HED subclasses. The overall composition is found to be mostly compatible with howardite meteorites, although a small area around 180°E longitude could be attributed to a diogenite-rich spot. We finally focus our spectral analysis on the characteristics of Vesta’s bright and dark regions as seen from Hubble Space Telescope’s visible and Keck-II’s near-infrared images.