CYRA (CrYogenic solar spectrogRAph) is a facility instrument of the 1.6-meter Goode Solar Telescope (GST) at the Big Bear Solar Observatory (BBSO). CYRA focuses on the study of the near-infrared solar spectrum between 1 and 5 microns, an under-explored region which is not only fertile ground for photospheric magnetic diagnostics but also allows a unique window into the chromosphere lying atop the photosphere. CYRA is the first-ever fully cryogenic spectrograph in any solar observatory with its two predecessors, on the McMath-Pierce and Mees Telescopes, being based on warm optics except for the detectors and order sorting filters. CYRA is used to probe magnetic fields in various solar features and the quiet photosphere. CYRA measurements will allow new and better 3D extrapolations of the solar magnetic field and will provide more accurate boundary conditions for solar activity models. The superior spectral resolution of 150,000 and better allows enhanced observations of the chromosphere in the carbon monoxide (CO) spectral bands and will yield a better understanding of energy transport in the solar atmosphere. CYRA is divided into two optical sub-systems: The Fore-Optics Module and the Spectrograph. The Spectrograph is the heart of the instrument and contains the IR detector, grating, slits, filters, and imaging optics all in a cryogenically cooled Dewar (cryostat). The sensor is a 2048 by 2048 pixel HAWAII 2 array produced by Teledyne Scientific and Imaging, LLC. The cryostat interior and the readout electronics are maintained at 90 Kelvin by helium refrigerant-based cryo-coolers, while the IR array is cooled to 30 Kelvin. The Fore-Optics Module de-rotates and stabilizes the solar image, provides scanning capabilities and transfers the GST image to the Spectrograph. CYRA has been installed and is undergoing its commissioning phase. This paper reports on the design, implementation, and operation of CYRA in detail. The preliminary scientific results have been highlighted as well.
In this paper we present Big Bear Solar Observatory’s (BBSO) newest adaptive optics system – AO-308. AO-308 is a result of collaboration between BBSO and National Solar Observatory (NSO). AO-308 uses a 357 actuators deformable mirror (DM) from Xinetics and its wave front sensor (WFS) has 308 sub-apertures. The WFS uses a Phantom V7.3 camera which runs at 2000 Hz with the region of interest of 416×400 pixels. AO-308 utilizes digital signal processors (DSPs) for image processing. AO-308 has been successfully used during the 2013 observing season. The system can correct up to 310 modes providing diffraction limited images at all wavelengths of interest.
The 1.6m New Solar Telescope (NST) has developed a modern and comprehensive suite of instruments which allow high resolution observations of the Sun. The current instrument package comprises diffraction limited imaging, spectroscopic and polarimetric instruments covering the wavelength range from 0.4 to 5.0 microns. The instruments include broadband imaging, visible and near-infrared scanning Fabry-Perot interferometers, an imaging spectropolarimeter, a fast visible-light imaging spectrograph, and a unique new scanning cryogenic infrared spectrometer/spectropolarimeter that is nearing completion. Most instruments are operated with a 308 subaperture adaptive optics system, while the thermal-IR spectrometer has a correlation tracker. This paper reports on the current observational programs and operational performance of the telescope and instrumentation. The current control, data processing, and archiving systems are also briefly discussed.
A multi-conjugate adaptive optics (MCAO) system is being built for the world's largest aperture 1.6m solar telescope, New Solar Telescope, at the Big Bear Solar Observatory (BBSO). The BBSO MCAO system employs three deformable mirrors to enlarge the corrected field of view. In order to characterize the MCAO performance with different optical configurations and DM conjugated altitudes, the BBSO MCAO setup also needs to be flexible. In this paper, we present the optical design of the BBSO MCAO system.
The 1.6-m New Solar Telescope (NST) has been used to observe the Sun for more than three years with ever
increasing capabilities as its commissioning phase winds down. The NST is the first facility-class solar telescope
built in the U.S. in a generation, and it has an off-axis design as is planned for the 4 m Advanced Technology
Solar Telescope. Lessons learned will be discussed. Current NST post-focus instrumentation includes adaptive
optics (AO) feeding photometric and near-IR polarimetric sytems, as well as an imaging spectrograph. On-going
instrumentation projects will be sketched, including Multi-Conjugate AO (MCAO), next generation (dual Fabry-
Perot) visible light and near-IR polarimeters and a fully cryogenic spectrograph. Finally, recent observational
results illustrating the high resolution capabilities of the NST will be shown.
New Jersey Institute of Technology, in collaboration with the University of Hawaii and the Korea Astronomy
& Space Science Institute, has successfully developed and installed a 1.6 m clear aperture, off-axis New Solar
Telescope (NST) at the Big Bear Solar Observatory. The NST will be the largest aperture solar telescope in the
world until the 4 m Advanced Technology Solar Telescope (ATST) and 4 m European Solar Telescope (EST)
begin operation in the next decade. Meanwhile, the NST will be the largest off-axis telescope before the 8.4 m
segmented Giant Magellan Telescope (GMT) comes on-line. The NST is configured as an off-axis Gregorian
system consisting of a parabolic primary, prime focus field stop and heat reflector, elliptical secondary and
diagonal flats. The primary mirror is made of Zerodur from Schott and figured to a final residual error of 16
nm rms by Steward Observatory Mirror Lab. The final focal ratio is f/52. The 180 circular opening in the
field stop defines the maximal square field-of-view. The working wavelength range will cover 0.4 to 1.7 μm in
the Coud´e Lab two floors beneath the telescope, and all wavelengths including far infrared at the Nasmyth focus
on an optical bench attached to the side of the telescope structure. First-light scientific observations have been
attained at the Nasmyth focus and in the Coud´e Lab. This paper presents a detailed description of installation
and alignment of the NST. First-light observational results are also shown to demonstrate the validity of the
NST optical alignment.
The largest solar telescope, the 1.6-m New Solar Telescope (NST) has been installed and is being commissioned
at Big Bear Solar Observatory (BBSO). It has an off-axis Gregorian configuration with a focal ratio of F/52.
Early in 2009, first light scientific observations were successfully made at the Nasmyth focus, which is located
on the east side of the telescope structure. As the first available scientific instruments for routine observation,
Nasmyth focus instrumentation (NFI) consists of several filtergraphs offering high spatial resolution photometry
in G-band 430 nm, Ha 656 nm, TiO 706 nm, and covering the near infrared 1083 nm, 1.6 μm, and 2.2 μm. With
the assistance of a local correlation tracker system, diffraction limited images were obtained frequently over a
field-of-view of 70 by 70 after processed using a post-facto speckle reconstruction algorithm. These data sets not
only serve for scientific analysis with an unprecedented spatial resolution, but also provide engineering feedback
to the NST operation, maintenance and optimization. This paper reports on the design and the implementation
of NFI in detail. First light scientific observations are presented and discussed.
The 1.6-meter New Solar Telescope (NST) is currently the world's largest aperture solar telescope. The NST
is newly built at Big Bear Solar Observatory (BBSO). Among other instruments, the NST is equipped with
several focal plane instruments operating in the near infrared (NIR). In order to satisfy the diverse observational
requirements of these scientific instruments, a 1024 × 1024 HgCdTe TCM8600 CMOS camera manufactured by
Rockwell Scientific Company has been repackaged and upgraded at Infrared Laboratories Inc. A new ND-5 dewar
was designed to house the TCM8600 array with a low background filter wheel, inverted operation and at least 12
hours of hold time between fills. The repackaged camera will be used for high-resolution NIR photometry at the
NST Nasmyth focus on the telescope and high-precision NIR spectro-polarimetry in the NST Coud´e Lab below.
In March 2010, this repackaged camera was characterized in the Coud´e Lab at BBSO. This paper presents the
design of new dewar, the detailed process of repackaging and characterizing the camera, and a series of test
The New Solar Telescope (NST) project at Big Bear Solar Observatory (BBSO) now has all major contracts
for design and fabrication in place and construction of components is well underway. NST is a collaboration
between BBSO, the Korean Astronomical Observatory (KAO) and Institute for Astronomy (IfA) at the University
of Hawaii. The project will install a 1.6-meter, off-axis telescope at BBSO, replacing a number of older solar
telescopes. The NST will be located in a recently refurbished dome on the BBSO causeway, which projects
300 meters into the Big Bear Lake. Recent site surveys have confirmed that BBSO is one of the premier solar
observing sites in the world. NST will be uniquely equipped to take advantage of the long periods of excellent
seeing common at the lake site. An up-to-date progress report will be presented including an overview of the
project and details on the current state of the design. The report provides a detailed description of the optical
design, the thermal control of the new dome, the optical support structure, the telescope control systems, active
and adaptive optics systems, and the post-focus instrumentation for high-resolution spectro-polarimetry.
The InfraRed Imaging Magnetograph (IRIM)1,2 is a two-dimensional narrow-band solar spectro-polarimeter currently being developed at Big Bear Solar Observatory (BBSO). It works in the near infrared (NIR) from 1.0 μm to 1.7 μm and possesses high temporal resolution, high spatial resolution, high spectral resolving power, high magnetic sensitivity. As the detector of IRIM, the 1024 × 1024 HgCdTe TCM8600 CMOS camera manufactured by the Rockwell Scientific Company plays a very important role in acquiring the high precision solar spectropolarimetry data. In order to make the best use of it for solar observation, the characteristic evaluation was carried out at BBSO and National Solar Observatory (NSO), Sacramento Peak in October 2003. The paper presents a series of measured performance parameters including linearity, readout noise, gain, full well capacity, hot pixels, dark, flat field, frame rate, vacuum, low temperature control, etc., and shows some solar infrared narrow band imaging observation results.
The spectral line of HeI 1083nm is important and potential to measure the magnetic field of the solar upper chromosphere. In this paper, we present a newly developed Stokes polarimeter for measuring the polarized signals at this wavelength. In this device, two Liquid Crystal Variable Retarders (LCVRs) were employed as electro-optical modulators and a Wollaston prism as analyzer and polarized beam splitter. Compared to the commonly used linear-polarized analyzer, the Wollaston prism analyzer has main advantage to minimize the seeing-induced contamination of earth's atmosphere, as it produces simultaneous images by the two perpendicular polarization states. A novel optical design which focuses the two beams on different detector areas is described. And the accurate calibration methods are introduced too.
The tunable near InfraRed Lyot filter (TNIRLF) is one of the focal plane instruments for Advanced Technology Solar Telescope (ATST) project of the National Solar Observatory (NSO). Achromatic half waveplate and quarter waveplates working from 1000 nm to 1700 nm will be used in this filter. In this paper, we give a description of the design and development for the synthesized achromatic waveplates using quartz plates. The retardance variation is within 1% over the full spectral range and we discuss the variance of optical axis.
The waveplate made of Polyvinyl Alcohol (PVA) plastic film has several advantages compared with that of birefringent crystal in visible region, such as its lower cost and insensitivity to temperature and incidence angle. What are the performances when they are used in the near infrared spectral region? In this paper, we provide some experimental results of infrared PVA waveplates. To do this, we make some samples and measure their polarization characteristics at several aspects. Firstly, we measure the performance of these PVA waveplates by precise instruments in laboratory. Secondly, we put the waveplates into a Stokes polarimeter to observe the solar magnetic field at near infrared line FeI1.56μm. By use of this polarimeter mounted on the vertical spectrograph of 2m McMath telescope at Kitt Peak, the two-dimensional Stokes parameters, I, Q, U, and V, of a sunspot were observed. From the results of laboratory and observation, we get the conclusion that PVA waveplate has the fair polarization performance to be used to observe the solar magnetic fields in the near infrared spectral region. By these experiments, we provide a design of an achromatic waveplate in infrared region, which consists of five-element, to illustrate the PVA waveplate is the best choice to it.
The InfraRed Imaging Magnetograph (IRIM) is a high temporal resolution, high spatial resolution, high spectral resolving power, and high magnetic sensitivity solar two-dimensional narrow-band spectro-polarimeter working in the near infrared from 1.0 μm to 1.7 μm at Big Bear Solar Observatory (BBSO). It consists of an interference filter, a polarization analyzer, a birefringent filter, and a Fabry-Perot etalon. As the narrowest filter of IRIM, the infrared Fabry-Perot plays a very important role in achieving the narrow band transmission of ~ 10 pm and high throughput between 85% and 95% for the full wavelength range, maintaining wavelength tuning ability from 1.0 to 1.7 μm, and assuring stability and reliability. As the third of a series of publications describing IRIM, this paper outlines a set of methods to evaluate the near infrared Fabry-Perot etalon. Two-dimensional characteristic maps of the near infrared Fabry-Perot etalon, including the bandpass ▵λ, effective finesse Feff, peak transmission τmax, along with a free spectral range, flatness, roughness, and stability and repeatability were obtained with laboratory equipment. These measured results will benefit the optimization of IRIM design and observational mode of the future.
FeI 1.56 micrometers Zeeman-sensitive lines are very important and potential to measure the magnetic field of the deepest layer of the solar photosphere. The new generation polarimeter is designed and manufactured in this wavelength range. By use of the polarimeter mounted on the vertical spectrograph of the 2m solar telescope at Kitt Peak, we can observe the Stokes I, Q, U, Vv parameters simultaneously. The paper presents the introduction of the near infrared polarimeter and the polarmetry of a sunspot group.
The Solar Space Telescope (SST) is the largest scientific space project of China up to now. It engages to observe the transient and steady state solar hydrodynamic and magneto-hydrodynamic process over 2-D real time polarizing spectrum, UV, X-ray and H(alpha) image, and continuous time evolution with high spatial and temporal resolution in order to achieve a break through advance in solar physics. The EUV part of SST, the EUV telescope (EUT), consists of four telescopes with their detectors, which are parallel situated in a single telescope tube. Each telescope of the EUT adopts the normal-incidence principle with help of the multilayer technology and the primary mirror diameter is 12cm. The detectors of the EUT are constructed with EUV sensitive phosphors, fiber tapers, image intensifiers, CCDs, camera electronics and cooling blocks. Three telescopes of EUT are designed to achieve a spatial resolution of 0.5 arcsecond with a field of view (FOV) of 8.5'x8.5' in order to get the ever high-resolution image of the fine structure of the high temperature activities in solar corona and the fourth one is 85'x85' to have the full solar disk always in its field of view. In our presentation, the scientific objectives and the configuration of EUT are introduced.
Although the interest in PtSi infrared focal plane array (IRFPA) has waned due to its low quantum efficiency compared with InSb and HgCdTe arrays, it is very potential in observing brighter celestial objects. We explored the possibility of applying it to the observation of infrared solar spectrum. In the paper, the methods of the simulation and calibration in our observation are introduced and discussed in detail. Using this kind of camera, a new observational band (FeI 1.56 micrometers ) is added to the Two- Dimensional Multi-Band Solar Spectrograph at Yunnan Observatory. The dispersion for FeI 1.56 micrometers of the new infrared solar spectrograph is 0.0722 angstrom per pixel, and each vertical pixel represents 0.51 inch of solar disk. It is specially suitable for 2D spectroscopic observation of the deepest solar photosphere. Some primary observation results are also presented.
Although the interest in PtSi IR focal pane array has waned due to its low quantum efficiency compared with InSb and HgCdTe arrays, it is very potential in observing brighter celestial objects. We explored the possibility of applying it to the observation of IR solar spectrum. In the paper, the methods of the simulation and calibration in our observation are introduced and discussed in detail. Using this kind of camera, a new observational band is added to the 2D Multi-band Solar Spectrograph at Yunnan Observatory. The dispersion for FeI 1.56 micrometers of the new IR solar spectrograph is 0.0722 angstrom per pixel, and each vertical pixel represents 0.51 inch of solar disk. It is specially suitable for 2D spectroscopic observation of the deepest solar photosphere. Some primary observation results are also presented.
On Mar. 6-7, 1997, a simultaneous remote observation from 6 sites was successfully carried out with the cooperation of astronomers and hobbyists in China, United States, Canada, and Great Britain. In the paper, the process and technical methods in this observation are introduced in detail. The present difficulties and brilliant prospects in the observational method under the current circumstances of Internet in China are shown as well.
The methods of evaluating the astronomy-using CCDs in Yunnan Observatory CCD-testing Lab are introduced, concerning the evaluation of linearity, noise, gain, quantum efficiency and transfer efficiency, etc.
Two remote presence observations on Dec. 25, 1995 and Mar. 7, 1997 were achieved at the 1-m telescope of Yunnan Observatory. In this paper, the observations are introduced in detail. The technical methods in the remote presence observation are also discussed under the current circumstances of hardware and software in China. The brilliant prospects of the observational method are shown as well.