scholarly journals Chromospheric telescope of Baikal Astrophysical Observatory. New light

2016 ◽  
Vol 2 (2) ◽  
pp. 82-103
Author(s):  
Валерий Скоморовский ◽  
Valery Skomorovsky ◽  
Галина Кушталь ◽  
Galina Kushtal ◽  
Любовь Лоптева ◽  
...  
Keyword(s):  
Ccd Camera ◽  
Spectral Parameters ◽  
Optical Elements ◽  
Wavefront Distortion ◽  
Solar Research ◽  
Telescope Optics ◽  
Synoptic Observations ◽  
First Time ◽  
Optical Immersion ◽  
Full Disk

A chromospheric telescope is an important instrument for synoptic observations and solar research. After several decades of observations with the chromospheric telescope at the Baikal Astrophysical Observatory, a need arose to improve the characteristics of this telescope and filter. A new reimaging lens to produce full-disk solar images 18 mm in diameter at the CCD camera Hamamatsu C-124 with a 36×24 mm detector (4000×2672 pixels) was designed and manufactured to replace the out-of-operation 50×50 mm Princeton Instruments camera. A contrast interference blocking filter and new calcite and quartz crystal plates were made and installed instead of damaged ones in the Hα birefringent filter (BF), manufactured by Bernhard Hallе Nachfl. The optical immersion in the filter was changed. All telescope optics was cleaned and adjusted. We describe for the first time the design features and their related BF passband tuning. The wavefront interferograms of optical elements and telescope as a whole show that the wavefront distortion of the optical path is within 0.25 λ. The BF and prefilter spectral parameters provide high-contrast monochromatic images. Besides, we give examples of solar chromospheric images in the Hα line core and wing.

Chromospheric telescope of Baikal Astrophysical Observatory. New light

2016 ◽  
Vol 2 (2) ◽  
pp. 69-85 ◽  
Author(s):  
Валерий Скоморовский ◽  
Valery Skomorovsky ◽  
Галина Кушталь ◽  
Galina Kushtal ◽  
Любовь Лоптева ◽  
...  
Keyword(s):  
Ccd Camera ◽  
Spectral Parameters ◽  
Optical Elements ◽  
Wavefront Distortion ◽  
Solar Research ◽  
Telescope Optics ◽  
Synoptic Observations ◽  
First Time ◽  
Iceland Spar ◽  
Optical Immersion

A chromospheric telescope is an important instrument for synoptic observations and solar research. After several decades of observations with the chromospheric telescope at Baikal Astrophysical Observatory, a need arose to improve the characteristics of this telescope and filter. A new reimaging lens to produce full-disk solar images 18 mm in diameter at the CCD camera Hamamatsu C-124 with a detector 36×24 mm (4000×2672 pixels) was designed and manufactured to replace the out-of-operation 50×50 mm Princeton Instruments camera. A contrast interference blocking filter and a new Iceland spar and quartz crystal plates instead of damaged ones were made and installed in the Hα birefringent filter (BF), manufactured by Bernhard Hallе Nachfl. The optical immersion in the filter was changed. All telescope optics was cleaned and adjusted. We describe for the first time the design features and their related BF passband tuning. The wavefront interferograms of optical elements and telescope as a whole show that the wavefront distortion of the optical path is within 0.25 λ. The BF and pre-filter spectral parameters provide high-contrast monochromatic images. Besides, we give examples of solar chromospheric images in the Ha line core and wing.

scholarly journals Polarization calibration techniques and scheduling for the Daniel K. Inouye Solar Telescope

2014 ◽  
Vol 10 (S305) ◽  
pp. 102-107
Author(s):  
David F. Elmore
Keyword(s):  
Advanced Technology ◽  
Optical Coatings ◽  
Calibration Error ◽  
Solar Telescope ◽  
Critical Importance ◽  
Common Path ◽  
Solar Research ◽  
Telescope Optics ◽  
The Individual ◽  
Calibration Techniques

AbstractThe Daniel K. Inouye Solar Telescope (DKIST), formerly Advanced Technology Solar Telescope when it begins operation in 2019 will be by a significant margin Earth's largest solar research telescope. Science priorities dictate an initial suite of instruments that includes four spectro-polarimeters. Accurate polarization calibration of the individual instruments and of the telescope optics shared by those instruments is of critical importance. The telescope and instruments have been examined end-to-end for sources of polarization calibration error, allowable contributions from each of the sources quantified, and techniques identified for calibrating each of the contributors. Efficient use of telescope observing time leads to a requirement of sharing polarization calibrations of common path telescope components among the spectro-polarimeters and for those calibrations to be repeated only as often as dictated by degradation of optical coatings and instrument reconfigurations. As a consequence the polarization calibration of the DKIST is a facility function that requires facility wide techniques.

scholarly journals Visible AO Observations at Halpha for Accreting Young Planets

2013 ◽  
Vol 8 (S299) ◽  
pp. 32-33
Author(s):  
L.M. Close ◽  
K. Follette ◽  
J.R. Males ◽  
K. Morzinski ◽  
T.J. Rodigas ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Binary Stars ◽  
Optical Resolution ◽  
Ccd Camera ◽  
Short Exposure ◽  
Low Mass ◽  
Orion Trapezium ◽  
First Time ◽  
Adaptive Optics System ◽  
Very High

AbstractWe utilized the new high-order (250-378 mode) Magellan Adaptive Optics system (MagAO) to obtain very high-resolution science in the visible with MagAO's VisAO CCD camera. In the good-median seeing conditions of Magellan (0.5–0.7″) we find MagAO delivers individual short exposure images as good as 19 mas optical resolution. Due to telescope vibrations, long exposure (60s) r' (0.63μm) images are slightly coarser at FWHM = 23-29 mas (Strehl ~ 28%) with bright (R < 9 mag) guide stars. These are the highest resolution filled-aperture images published to date. Images of the young (~ 1 Myr) Orion Trapezium θ1 Ori A, B, and C cluster members were obtained with VisAO. In particular, the 32 mas binary θ1 Ori C1C2 was easily resolved in non-interferometric images for the first time. Relative positions of the bright trapezium binary stars were measured with ~ 0.6–5 mas accuracy. In the second commissioning run we were able to correct 378 modes and achieved good contrasts (Strehl>20% on young transition disks at Hα). We discuss the contrasts achieved at Hα and the possibility of detecting low mass (~ 1–5 Mjup) planets (past 5AU) with our new SAPPHIRES survey with MagAO at Hα.

scholarly journals Phase-Shift Optimization in AA/PVA Photopolymers by High-Frequency Pulsed Laser

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1887
Author(s):  
Daniel Puerto ◽  
Sergi Gallego ◽  
Jorge Francés ◽  
Andrés Márquez ◽  
Inmaculada Pascual ◽  
...  
Keyword(s):  
Phase Shift ◽  
High Frequency ◽  
Large Scale ◽  
Pulsed Laser ◽  
Laser Exposure ◽  
Continuous Laser ◽  
Frequency Limit ◽  
Optical Elements ◽  
First Time ◽  
532 Nm

Photopolymers can be used to fabricate different holographic optical elements, although maximization of the phase-shift in photopolymers has been a challenge for the last few decades. Different material compositions and irradiation conditions have been studied in order to achieve it. One of the main conclusions has been that with continuous laser exposure better results are achieved. However, our results show for the first time that higher phase-shift can be achieved using a pulsed laser. The study has been conducted with crosslinked acrylamide-based photopolymers exposed with a pulsed laser (532 nm). The increment of the phase-shift between the pulsed laser and continuous laser exposure is 17%, achieving a maximum phase-shift of 3π radians and a refractive index shift of 0.0084 at the zero spatial frequency limit, where monomer diffusion does not take place. This allows this photopolymer to be used in large-scale manufacturing.

scholarly journals First high-resolution look at the quiet Sun with ALMA at 3mm

2018 ◽  
Vol 619 ◽  
pp. L6 ◽  
Author(s):  
A. Nindos ◽  
C. E. Alissandrakis ◽  
T. S. Bastian ◽  
S. Patsourakos ◽  
B. De Pontieu ◽  
...  
Keyword(s):  
High Resolution ◽  
Brightness Temperature ◽  
Disk Center ◽  
Image Resolution ◽  
Quiet Sun ◽  
Chromospheric Network ◽  
Local Background ◽  
First Time ◽  
Full Disk

We present an overview of high-resolution quiet Sun observations, from disk center to the limb, obtained with the Atacama Large millimeter and sub-millimeter Array (ALMA) at 3 mm. Seven quiet-Sun regions were observed at a resolution of up to 2.5″ by 4.5″. We produced both average and snapshot images by self-calibrating the ALMA visibilities and combining the interferometric images with full-disk solar images. The images show well the chromospheric network, which, based on the unique segregation method we used, is brighter than the average over the fields of view of the observed regions by ∼305 K while the intranetwork is less bright by ∼280 K, with a slight decrease of the network/intranetwork contrast toward the limb. At 3 mm the network is very similar to the 1600 Å images, with somewhat larger size. We detect, for the first time, spicular structures, rising up to 15″ above the limb with a width down to the image resolution and brightness temperature of ∼1800 K above the local background. No trace of spicules, either in emission or absorption, is found on the disk. Our results highlight the potential of ALMA for the study of the quiet chromosphere.

scholarly journals Boxy Isophotes and Dust Lanes in Bright Virgo Ellipticals

1987 ◽  
Vol 127 ◽  
pp. 409-410
Author(s):  
C. Möllenhoff ◽  
R. Bender
Keyword(s):  
Color Index ◽  
Ccd Camera ◽  
Major Axis ◽  
Elliptical Galaxies ◽  
Virgo Cluster ◽  
Least Square ◽  
Semi Major Axis ◽  
Morphological Studies ◽  
Main Indicator ◽  
First Time

The CCD camera of the Landessternwarte Heidelberg was used at the 1.2 m Calar Alto Telescope for a V, R, I - survey of ~70 dusty and non-dusty elliptical galaxies. We report here about morphological studies of ten bright elliptical galacxies in the Virgo cluster. After the usual CCD data reduction the following procedures were carried through:1. The CCD-frames were filtered and centered to an accuracy of ~ 0. 2 pixels. By division we obtained V-R, V-I, R-I color index images which allow to separate dust absorption and gaseous emission from the stellar distribution. Five of the 1 0 bright Virgo ellipticals evidently show dust/gas, two other objects have weak features. The dust lanes in NGC k26 (cf. Fig. l), NGC 4365 and NGC 4552 were detected for the first time. A dust lane must be visible in all three color index frames in order to avoid fake identifications.2. The isophotes in all three colors were fitted by least square ellipses. From these fits we obtained in dependence from the radius: color profiles, color index profiles, ellipticity profiles, isophote twists (cf. Fig. 2). The deviations of the isophotes from ideal ellipses were studied by a Fourier series analysis. The fourth coefficient is the main indicator for such deviations. Six of ten galaxies show box-shaped isophotes of an amount between 0. 3 % and 1. 5 % of the semi major axis (cf. Fig. 3) 5 two galaxies show disc components (0. 8 1.5 %), only one galaxy is a perfect elliptical up to an error of ±0.2 %. The deviations are equal in all three colors and therefore are not produced by dust.

scholarly journals Solar observations at the Coimbra Astronomical Observatory

2019 ◽  
Vol 28 (1) ◽  
pp. 165-179 ◽  
Author(s):  
Ana Lourenço ◽  
Sara Carvalho ◽  
Teresa Barata ◽  
Adriana Garcia ◽  
Víctor Carrasco ◽  
...  
Keyword(s):  
Ccd Camera ◽  
Astronomical Observatory ◽  
Photographic Emulsion ◽  
Digital Recording ◽  
Solar Observations ◽  
Synoptic Observations ◽  
Data Collections ◽  
The University ◽  
Near Future

Abstract In 2020, the Geophysical and Astronomical Observatory of the University of Coimbra will celebrate the 95th anniversary of its first spectroheliographic observation. Keeping a daily service of solar observations since then, making almost a century, led to one of the largest continuous solar data collections in the world. This long–term solar database is essential for studies where solar activity is involved. This work reviews the development of synoptic observations made at the Observatory of Coimbra since 1925 and presents a summary of some of the principal stages of the Observatory’s history since its founding in 1772. We refer the main technical improvements and present some perspectives for the near future. One of the most significant upgrades was the installation of a CCD camera in 2007. The transition from photographic emulsion to digital recording methods allowed the development of image analysis algorithms to process solar images and improved data sharing with other institutions. This upgrade enabled also to carry–out modern climate and space weather studies. This valuable advancement makes it possible to create a new catalogue of solar observations to be published in the future.

scholarly journals Nachweis der Atropisomerie peri-substituierter Naphthalin-Derivate durch dynamische 1H-NMR-Spektroskopie / Dynamic 1H-NMR-Spectroscopic Evidence for the Atropisomerism of Perisubstituted Naphthalene Derivatives

1977 ◽  
Vol 32 (8) ◽  
pp. 912-933 ◽  
Author(s):  
Reiner Luckenbach ◽  
Axel Jensen
Keyword(s):  
1H Nmr ◽  
Chiral Molecules ◽  
Kcal Mole ◽  
Naphthalene Derivatives ◽  
Spectral Parameters ◽  
Hindered Rotation ◽  
H Nmr ◽  
Environment Temperature ◽  
Dynamic 1H Nmr ◽  
First Time

The preparation of the perisubstituted naphthalene derivatives 1-8 is described for the first time, and possible axial or axial and planar chirality of these compounds is investigated by means of dynamic 1H NMR spectroscopy. Molecular chirality, caused by hindered rotation, can be proven for compounds 1 and 3 at room temperature and for 2 at 193 K by the observation of magnetic inequivalence of isochronous protons in a diastereotopic environment. Temperature-dependent 1H NMR spectra indicate that for 2 the coalescence temperature lies between 193 K and 213 K, and above 320 K for 3. By assuming Tcoal- = 200 K for 2 and Tcoal. > 320 K for 3 the following ⊿G≠-values were estimated with the aid of known approximations from the 1H NMR spectral parameters Δν = νA-νB and JAB for the methylene and methyl groups of the oxazoline system present in these species: ⊿G≠ (2) = 10.1 kcal/mole (at 200 K), ⊿G≠ (3) = 17.3 (16.2) kcal/mole (at 320 K). These ⊿G≠-values represent the energy barriers of a dynamic intramolecular process, presumably according to a more or less hindered rotation in the purely axially chiral molecules 2 and 3. With the aid of these ⊿G≠-values and model considerations a description of the energy profile diagram of the hindered rotation in compounds 2 and 8 is attempted.

Full-Disk solar Dopplergrams observed with a 1024 × 1024-Pixel CCD Camera

1988 ◽  
Vol 123 ◽  
pp. 471-474
Author(s):  
Edward J. Rhodes ◽  
Alessandro Cacciani ◽  
Steven Tomczyk
Keyword(s):  
Spatial Resolution ◽  
Optical Filter ◽  
Ccd Camera ◽  
Solar Oscillations ◽  
Heliospheric Observatory ◽  
Full Disk

We present here the first full-disk solar Dopplergram obtained with the new 1024 × 1024-pixel CCD camera which has recently been installed at the 60-Foot Tower Telescope of the Mt. Wilson Observatory. This Dopplergram has a spatial resolution of 2.2 arcseconds and was obtained in less than one minute of time. The Dopplergram was obtained with a magneto-optical filter which was designed to obtain images in the two Na D lines. The filter and the camera were operated together as part of the development of a Solar Oscillations Imager (SOI) esperiment which is currently being designed at JPL for the joint NASA/ESA Solar and Heliospheric Observatory (SOHO) mission.

New Initiatives for Synoptic Observations

2000 ◽  
Vol 179 ◽  
pp. 127-134
Author(s):  
C. U. Keller
Keyword(s):  
Solar Observatory ◽  
The Sun ◽  
National Solar Observatory ◽  
Synoptic Observations ◽  
Long Term Studies ◽  
Full Disk

AbstractSeveral new synoptic facilities for long-term studies of the Sun will become operational within the next few years. This paper summarizes information on some of these projects, in particular GONG+, ISOON, GOES/SXI, and SOUS. SOUS, the Synoptic Optical Long-Term Investigations of the Sun, is currently being built by the National Solar Observatory and will become operational in 2001. It consists of a 50-cm vector spectromagnetograph, a 14-cm full-disk patrol, and an 8-mm sun-as-a-star spectrometer.

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