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Transition region explosive events (EEs) have been observed with slit spectrographs since at least 1975, most commonly in lines of C IV (1548 A, 1550 A) and Si IV (1393 A, 1402 A). We report what we believe to be the first observation of a transition region EE in He II 304 A. With the Multi-Order Solar EUV Spectrograph (MOSES) sounding rocket, a novel slitless imaging spectrograph, we are able to see the spatial structure of the event. We observe a bright core expelling two jets that are distinctly non-collinear, in directions that are not anti-parallel. The jets have sky-plane velocities of order 75 km s-1 and line-of-sight velocities of +75 km s-1 (blue) and -30 km s-1 (red). The core is a region of high non-thermal Doppler broadening, characteristic of EEs, with maximal broadening 380 km s-1 FWHM. It is possible to resolve the core broadening into red and blue line-of-sight components of maximum Doppler velocities +160 km s-1 and -220 km s-1. The event lasts more than 150 s. Its properties correspond to the larger, long-lived, and more energetic EEs observed in other wavelengths.

We observed a transient brightening in the quiet Sun at rapid cadence (2.10 s) with the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS-06) sounding rocket instrument on 2006 April 12. The transient was visible only in He II at 303.78 A ( T [?] 5 x 104 K), and its maximum temperature T was < 4 x 105 K. Taking its linear extent along the EUNIS slit to be the diameter of a circular feature, the transient's solar surface area was 7.8 x 107 km2. EUNIS observed the brightening to begin at 18:12:52 and peak at 18:13:29 UT; coordinated observations with SOHO's EIT confirm that EUNIS observed the onset of the brightening. EUNIS spectra yield maximum and average He II intensity enhancements of 2.09 and 1.46, respectively, relative to the pre-event quiet Sun. He II line profiles from EUNIS reveal that relative upflows were persistent during the transient (with a maximum speed around 20 km s[?]1) and that the upflow speed and intensity were positively correlated. Variations in the observed He II intensity and relative Doppler velocity were neither abrupt not impulsive, but occurred slowly compared to the EUNIS cadence. The local photospheric longitudinal magnetic field strength measured with SOHO's MDI revealed no significant variability. The transient's measured properties are consistent with its identification as a blinker or an elementary blinker, and its observed behavior suggests a formation mechanism involving gentle chromospheric evaporation.

We present a well-calibrated EUV spectrum of a solar coronal bright point observed with the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket instrument on 2006 April 12. The coronal bright point brightened around 06:30 UT during a period of emerging magnetic flux and remained bright at least until the rocket flight around 18:12 UT, while the magnetic flux merged and canceled. Density-sensitive line intensity ratios yield mutually consistent coronal electron densities (Ne in cm[?]3) of log Ne [?] 9.4. The differential emission measure (DEM, in cm[?]5 K[?]1) curve derived from the spectrum yields a peak of log DEM [?] 20.70 at log T [?] 6.15 and a local minimum of log DEM [?] 20.15 at log T [?] 5.35. Photospheric (not coronal) element abundances are required to achieve equality and consistency in the DEM derived from lines of Mg V, Mg VI, Mg VII, and Ca VII (with a low first ionization potential, or FIP) and lines from Ne IV and Ne V (with a high FIP) formed at transition region temperatures. The bright point's photospheric abundance is likely produced by reconnection-driven chromospheric evaporation, a process that is not only central to existing bright point models, but also consistent with measurements of relative Doppler velocities.

A wavelength calibration of solar lines observed by the high resolution EUV Imaging Spectrometer (EIS) on the Hinode satellite is reported. Spectral features of the quiet sun and of two mildly active areas were measured and calibrated. A listing of the stronger observed lines with identification of the leading contributor ions is presented. 41 lines are reported, with 90% identified. Wavelength precisions (2$\sigma$) of $\pm$0.0031 Å for the EIS short band and $\pm$0.0029 Å for the EIS long band are obtained. These lines, typical of 1–$2\times 10^{6}$K plasmas, are recommended as standards for the establishment of EIS wavelength scales. The temperature of EIS varies by about $1\rlap{.}^{\circ}5$C around the orbit and also with spacecraft pointing. The correlation of these temperature changes with wavelength versus pixel number scale changes is reported.

The goal of the Hinode mission is to provide an observational basis for understanding the heating and acceleration of coronal plasmas. On 2007 January 20, the Extreme ultraviolet Imaging Spectrometer performed a raster of a quiet region near Sun center. Maps of intensities, velocities, and electron densities derived from these observations are presented and discussed. Intensity maps in He II $\lambda$256, formed at 9$\times$10$^4$K, show the chromospheric network. Line intensities of Fe X-XIV, formed at temperatures from 1–2$\times$10$^6$K, show small-scale bright points and more extended structures. The intensity map of Fe VIII shows a transition between the two temperatures. The coronal lines reveal regions of high outflow velocities on the order of 100 km s$^{-1}$in a compact region and 12 km s$^{-1}$in an extended region. The presence of such high velocities in the quiet corona is an entirely new and unexpected result. Electron densities derived from density sensitive line ratios of Fe XII and X III are typically 3–20$\times$10$^8$cm$^{-3}$. The highest densities are found in bright, compact areas. For the first time, explosive events in the quiet sun have been observed in the extreme-ultraviolet in He II $\lambda$256 profiles.

The Extreme-Ultraviolet Imaging Spectrometer (EIS) is the first of a new generation of normal-incidence, two-optical-element spectroscopic instruments developed for space solar extreme-ultraviolet astronomy. The instrument is currently mounted on the Solar-B satellite for a planned launch in late 2006. The instrument observes in two spectral bands, 170-210 Å and 250-290 Å. The spectrograph geometry and grating prescription were optimized to obtain excellent imaging while still maintaining readily achievable physical and fabrication tolerances. A refined technique using low ruling density surrogate gratings and optical metrology was developed to align the instrument with visible light. Slit rasters of the solar surface are obtained by mechanically tilting the mirror. A slit exchange mechanism allows selection among four slits at the telescope focal plane. Each slit is precisely located at the focal plane. The spectrograph imaging performance was optically characterized in the laboratory. The resolution was measured using the Mg iii and Ne iii lines in the range of 171-200 Å. The He ii line at 256 Å and Ne iii lines were used in the range of 251-284 Å. The measurements demonstrate an equivalent resolution of 2 arc sec on the solar surface, in good agreement with the predicted performance. We describe the EIS optics, mechanisms, and measured performance.

Performances are presented of three classes of imaging slit spectrometers for extended sources with aberration-corrected gratings. A general analytical expression for minimizing off-axis grating aberrations is obtained, and it is demonstrated that these aberrations are minimized when the spectrometer is operated at a magnification higher than unity. Classical designs with toroidal uniform-line-spaced (TULS) or spherical varied-line-space (SVLS) gratings are compared with a new class of designs that utilize toroidal varied-line-space (TVLS) gratings. Although TULS and SVLS designs with two stigmatic points can be designed to operate at near-unity magnification with excellent on-axis spectral and spatial resolutions, they cannot be made to satisfy the general off-axis condition, and so their off-axis performances are not optimum. On the contrary TVLS designs with two stigmatic points can be operated at almost any magnification, thus satisfying the off-axis condition perfectly. Such designs are suitable for imaging spectrometer observations that require an extended field of view.

Goddard Space Flight Center's Solar EUV Research Telescope and Spectrograph was flown on 1997 November 18, carrying an intensified CCD detector and a multilayer-coated toroidal diffraction grating with enhanced sensitivity over that of a standard gold-coated grating throughout the instrument's 299-353 A spectral bandpass. Spectra and spectroheliograms of NOAA Active Region 8108 (N21deg, E18deg) were obtained with a spectral resolution (instrumental FWHM) of 115 mA. Nearly 100 emission lines were observed in the spatially averaged active region spectrum. Spectra and spectroheliograms of quiet areas south of the region were also obtained. An end-to-end radiometric calibration of the rocket instrument was carried out at the Rutherford-Appleton Laboratory in the same facility that was used to calibrate the Coronal Diagnostic Spectrometer experiment on SOHO and using the same EUV light source. The accuracy of this calibration is confirmed by the excellent agreement between the measured and theoretical values of density- and temperature-insensitive line intensity ratios. Nine emission lines of Fe XV are identified in our spectrum; however, large differences between wavelengths in the CHIANTI database and some of the measured solar wavelengths, as well as inconsistencies of various theoretical intensity ratios, suggest a need for improvement in the Fe XV atomic physics parameters and/or the presence of unidentified blending lines. Density-sensitive line intensity ratios of Fe XI ll308.55/352.67, Fe XII ll338.27/352.11, Fe XIII ll320.80/312.17, and Fe XV ll321.78/327.03 yield logarithmic electron densities (in cm-3) of 9.92 +- 0.28, 9.74 +- 0.28, 9.52 +- 0.30, and 9.62 +- 0.26, respectively. Using the strongest emission line observed for each ionization stage of Fe from X through XVI and Ni XVIII, we find that all of the measured nonthermal line widths yield velocities consistent with 35 km s-1. The differential emission measure curve derived from the observed line intensities exhibits a relative minimum at log T ~ 5.7, a broad maximum centered around log T ~ 6.3, and a rapid decline for temperatures above log T ~ 6.6.

We present observational evidence of the effect of small-scale ("microturbulent") velocities in enhancing the intensity of the He II l304 line with respect to other transition region emission lines, a process we call "velocity redistribution,". We first show results from the 1991 and 1993 flights of SERTS (Solar EUV Rocket Telescope and Spectrograph). The spectral resolution of the SERTS instrument was sufficient to infer that, at the spatial resolution of 5'', the line profile is nearly Gaussian both in the quiet Sun and in active regions. We were then able to determine, for the quiet Sun, a lower limit for the amplitude of nonthermal motions in the region of formation of the 304 A line of the order of 10 km s-1. We estimated that, in the presence of the steep temperature gradients of the solar transition region (TR), velocities of this magnitude can significantly enhance the intensity of that line, thus at least helping to bridge the gap between calculated and observed values. We also estimated the functional dependence of such an enhancement on the relevant parameters (nonthermal velocities, temperature gradient, and pressure). We then present results from a coordinated campaign, using SOHO/CDS and Ha spectroheliograms from Coimbra Observatory, aimed at determining the relationship between regions of enhanced helium emission and chromospheric velocity fields and transition region emission in the quiescent atmosphere. Using these data, we examined the behavior of the He II l304 line in the quiet-Sun supergranular network and compared it with other TR lines, in particular with O III l600. We also examined the association of 304 A emission with the so-called coarse dark mottle, chromospheric structures seen in Ha red-wing images and associated with spicules. We found that all these observations are consistent with the velocity redistribution picture.

We used slit spectra from the 1995 flight of Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrograph (SERTS-95) to measure wavelength shifts of coronal emission lines in the core of NOAA active region 7870 relative to its immediate surroundings (its "edge"). This method circumvents the unavailability of reliable laboratory rest wavelengths for the observed lines by using wavelengths from the edge spectrum as references. We derived the SERTS-95 wavelength calibration from measurements of a post-flight laboratory spectrum containing 28 He II and Ne II EUV standard wavelengths known to high accuracy. Wavelength measurements for lines of He I, Ne III, and additional lines of Ne II in the laboratory calibration spectrum provide more accurate values than were previously available, enabling these lines also to serve as future calibration standards. Six solar lines were chosen for this study, namely, He II at 303.78 A, Fe XII at 193.51 A, Fe XIII at 202.05 A, Fe XIV at 211.33 A, Fe XV at 284.15 A, and Fe XVI at 335.41 A. Because these lines are free from known blends in the SERTS-95 spectra and are either intrinsically strong or near the SERTS-95 peak sensitivity, they are our most reliable lines for measuring relative wavelength shifts in the spatially resolved active-region core spectra. The iron ions are the hottest ions ever used for this type of analysis. All six lines reveal statistically significant spatial variations in their measured relative wavelength shifts in the active-region core, including mixtures of blueshifts and redshifts (each with maximum values corresponding to relative Doppler velocities ~15 km s-1), indicating a dynamic, turbulent corona. For each of these lines we calculated weighted-average relative Doppler velocities from the wavelength shifts in the spatially resolved core spectra by weighting the shifts in the individual spatial pixels with their respective measurement uncertainties. This yields velocities of 3.3 +- 1.1 km s-1 for He II, 5.2 +- 1.6 km s-1 for Fe XII, 0.7 +- 1.5 km s-1 for Fe XIII, -2.1 +- 1.4 km s-1 for Fe XIV, 1.0 +- 1.1 km s-1 for Fe XV, and -1.1 +- 0.8 km s-1 for Fe XVI. We also calculated intensity-weighted relative Doppler velocities from the wavelength shifts in the spatially averaged core spectrum, obtaining corresponding values of 5.8 +- 0.6 km s-1, 5.7 +- 0.9 km s-1, 0.4 +- 0.7 km s-1, -2.1 +- 1.0 km s-1, 0.8 +- 0.8 km s-1, and -1.1 +- 0.5 km s-1. Combining the above six lines with several additional ones that are strong enough in both the edge and average core spectra to provide reliable centroid measurements, we find statistically significant net relative redshifts for lines of He II, Fe X, Fe XI, and Fe XII; lines of Fe XIII and Fe XV show no significant shift while lines of Si XI, Fe XIV, and Fe XVI show a small net relative blueshift. Where multiple lines are available for a given ion, the directions (red or blue) and magnitudes (except for Fe XI) of the relative shifts are mutually consistent. The net relative blueshift observed in the hottest active-region coronal lines in our sample, combined with the net relative redshift observed in the cooler active-region coronal lines, suggests a net upflow of heated material cospatially and cotemporally with a net downflow of cooler material.

The coronal hole observed on May 31, 1973 is studied using extreme ultraviolet and radio observations. The EUV line is the Fe xv at ? = 284 Å and the radio frequencies are 169 and 408 MHz. An unsuccessful attempt to deduce an homogeneous model of the hole from these observations, shows that EUV and radio observations are inconsistent if interpreted in such a frame and if the EUV line intensity measurements in the hole are reliable.

A method is described for aligning cylindrical glancing incidence mirrors and establishing fiducials prior to axial profile measurements. The residual uncertainty in the absolute axial position is 2.54 μm and the uncertainty in the absolute radius is 0.812 μm.

Experimental results for image quality and scatter in far-UV light are used to choose between the conventionally polished Solar Extreme-Ultraviolet Rocket Telescope and Spectrograph (SERTS-A) and computer-controlled polished SERTS-C Wolter type II solar rocket telescopes for an extreme-UV flight instrument. In 124-nm light the SERTS-C telescope image had a 0.67-arcsec full width at half-maximum (FWHM), compared with a 1.25-arcsec FWHM for the SERTS-A telescope. In addition SERTS-C had twice the peak irradiance of SERTS-A and an order of magnitude lower near-angle scatter. The inflight performance of the telescopes is consistent with laboratory findings.

The performance of a multilayer coated diffraction grating has been evaluated at EUV wavelengths both in terms of absolute efficiency and spectral resolution. The application of a ten-layer Ir/Si multilayer coating to a 3600-lines/mm blazed toroidal replica grating produced a factor of 9 enhancement in peak efficiency near the design wavelength ~30 nm in first order, without degrading its excellent quasistigmatic spectral resolution. The measured EUV efficiency peaked at 3.3% and was improved over the full spectral range between 25 and 35 nm compared with the premultilayer replica which had a standard gold coating. In addition, the grating’s spectral resolution of >5000 was maintained.

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.

The RES-C grazing incidence XUV spectroheliograph has been developed in the P. N. Lebedev Physical Institute (FIAN) as a part of the CORONAS-I project. Its objective is to obtain images of the full Sun in monochromatic lines over the spectral range of 180–210Å, which includes prominent emission from ions of Fe VIII–Fe~XIII, O VI, and Fe XXIV. Here, we describe the optical scheme of the spectroheliograph, and show results of XUV testing of its individual component elements as well as of the complete assembled instrument. XUV measurements were made of the absolute diffraction efficiency and stray-light level for both holographic and mechanically ruled gratings, the spectral reflectivity of the multilayer-coated mirrors, the transmittance of the thin aluminum blocking filters, and the combined spectral efficiency of the whole instrument. The spectral and spatial resolutions of the spectroheliograph were measured by recording spectrally dispersed images of a laser plasma source in monochromatic lines of fluorine ions between 185–200Å. For comparison, we also present spectral images of the Sun obtained with the spectroheliograph as flown on the CORONAS-I satellite mission.

We observed NOAA region 7563 simultaneously with Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrogaph (SERTS) and with the Very Large Array (VLA) on 1993 August 17. SERTS obtained spectra in the 280-420 A wavelength range, and images in the lines of Mg IX l368.1, Fe XV l284.1, and Fe XVI l335.4. The VLA obtained microwave images at 20 and 6 cm wavelengths. The microwave emission depends upon the coronal temperature, density, column emission measure, and magnetic field; therefore, the coronal magnetic field can be derived when all of these other quantities are measured. Here we demonstrate this approach by using the SERTS data to derive all the relevant plasma parameters and then fitting the radio observations to a magnetic field model in order to determine the magnetic field structure. We used the method of Monsignori-Fossi & Landini and the coronal elemental abundances of Feldman et al. to derive the differential emission measure (DEM) curve for region 7563 from numerous EUV emission lines in spatially averaged SERTS spectra. A similar curve was estimated for each point (i.e., each pixel or each spatial location) in the two-dimensional region by scaling the average DEM curve with corresponding pixel intensities in the Mg IX, Fe XV, and Fe XVI images. We integrated each such DEM over narrow temperature ranges to obtain the column emission measure (CEM) as a function of temperature, CEM(T). We also obtained electron density measurements from EUV line intensity ratios in the spatially averaged spectrum for several ionization stages of iron. These were used to derive a functional relation between density and temperature, ne(T). We derived the temperature dependence of the coronal magnetic field [B(T)] at each point in the two-dimensional region by incorporating CEM(T) and ne(T) into expressions for the thermal bremsstrahlung and the gyroresonance opacities, and varying B(T) so as to minimize the difference between the calculated and the observed microwave intensities. The resulting calculated 20 and 6 cm microwave intensity images reproduce the observed images very well. We found that thermal bremsstrahlung alone is not sufficient to produce the observed microwave intensities: gyroemission is required. Further, contrary to several earlier studies, we found no evidence for cool, absorbing plasma in the solar corona above the active region. The coronal magnetic fields derived with our method typically exceed the coronal fields extrapolated with a simple potential model, suggesting the presence of coronal electric currents. However, in the diminutive sunspot which dominates the 6 cm emission this difference is relatively small, suggesting that the sunspot magnetic field itself is nearly potential. Although we cannot firmly establish the uniqueness of our solution in this particular case, the method is quite powerful and should be repeated with other similar data sets. Variations in the coronal elemental abundances could affect the determination of the microwave emission mechanism(s), introduce evidence for the presence of cool coronal plasma, and alter the strengths of the derived coronal magnetic fields.

We observed two solar active regions (NOAA regions 7563 and 7565), quiet-Sun areas, and a coronal hole region simultaneously with Goddard Space Flight Center's Solar EUV Rocket Telescope and Spectrograph (SERTS) and with the YohkohSoft X-ray Telescope (SXT) on 1993 August 17. SERTS provided spatially resolved active region and quiet-Sun slit spectra in the 280 to 420 Å wavelength range, and images in the lines of He II?303.8, Mg IX?368.1, Fe XV?284.1, and Fe XVI??335.4 and 360.8 SXT provided images through multiple broadband filters in both the full-frame imaging mode and the partial-frame imaging mode.

The elements of a Wolter type II telescope have been fabricated using a small area tool in a computer controlled facility. The absolute radius of the mirrors can be established to 0.812 μm, and relative heights on the surfaces can be determined to 0.016 μm. The primary has a 0.041-μm rms surface error, and the secondary has a 0.054-μm surface error.

EUV spectral lines of Mg VIII have been observed from the solar corona by Skylab, SERTS, and more recently by SOHO. Atomic data for this astrophysically important ion are presented in this paper. The atomic data include energy levels, oscillator strengths, transition rates, and electron-impact excitation collision strengths. Twenty levels are included by using the configurations 2s22p, 2s2p2, 2p3, 2s23s, 2s23p, and 2s23d. Collision strengths are calculated at five incident energies (15.0, 22.5, 30.0, 37.5, and 45.0 Ry) in the distorted wave approximation. The temperature of maximum abundance for this ion is log Te = 5.9 K. The rate coefficients are calculated at this temperature by averaging the collision strengths over a Maxwellian distribution. Proton rates and solar background radiation have been included in calculating level populations, and intensity ratios are calculated by including proton rates only. The relative intensity ratios are compared with observed ratios obtained from SERTS and SOHO/CDS to infer electron density in different solar features such as an active region, quiet-Sun, and off-limb. With a few exceptions, the predicted intensity ratios match observed values very well over a variety of instrumentation and solar conditions. Since Mg VIII has a number of strong EUV lines, we expect that the spectra of this ion should prove useful for abundance studies and other plasma diagnostics.

Soft solar X-rays (8 ? gl ? 12 Å) were observed from OSO-III. An analysis of the X-ray enhancements associated with 165 solar flares revealed that there is a tendency for a weak soft X-ray enhancement to precede the cm-? burst and Ha flare. The peak soft X-ray flux follows the cm-? peak by about 4 min, on the average. Additionally, it was found that flare-rich active centers tend to produce flares which are stronger X-ray and cm-? emitters than are flares which take place in flare-poor active centers.

Peak fluxes of flare-associated 8–12 Å X-ray bursts occur at or near the time of the maximum energy content of the soft X-ray source volume. The amplitudes of flare-associated bursts may thus be used as a measure of the energy deposited in the source volume by non-thermal electrons and other processes. In the mean, the soft X-ray burst amplitude is apparently independent of the occurrence of a type III event. This is interpreted to indicate that electrons accelerated by the type III process do not directly participate in establishing the soft X-ray source volume.

Flare-associated soft X-ray bursts (8–12 Å) are examined for 283 events observed by OSO-III. These bursts are shown to be predominantly thermal in nature. Their time-profiles are roughly similar to those of the associated Ha flares, although the X-ray burst begins about two minutes earlier, on the average. The strength of the soft X-ray burst is directly related to the area and brilliance of the flare, the age and ‘flare-richness’ of the associated plage, and the general level of solar activity at the time of the burst. The peak enhancements in the soft X-ray and Ha emission rates during flares are of the same order of magnitude, as are the total flare energies radiated at these wavelengths. We estimate that soft X-radiation accounts for up to 10% of a flare's total electromagnetic emission.

The article focuses on the history of the Lines of Torres Vedras, a line of forts built to defend Lisbon, Portugal during the Peninsular War. It states that the origins of the Lines come from a survey and proposals made by Portuguese army engineer Major Jose Maria das Neves Costa, but it was Arthur Wellesley, Viscount Wellington, who ordered its construction. The reason behind the construction of military roads to the rear of the Lines is cited. The article also talks about the role of the English Heritage in restoring the Lines.

Performance of multilayer coated diffraction gratings has been evaluated in the extreme UV. The application of multilayer coatings to two blazed gratings has produced a significant enhancement in grating efficiency in the 300-Å spectral region in first order.

A personal narrative is presented which explores the author's experience of a visit to the mustard gas factory at Rhydymwyn, near Mold in Wales.

We present a summary of the solar observing Rapid Acquisition Imaging Spectrograph Experiment (RAISE) sounding rocket program including an overview of the design and calibration of the instrument, flight performance, and preliminary chromospheric results from the successful November 2014 launch of the RAISE instrument. The RAISE sounding rocket payload is the fastest scanning-slit solar ultraviolet imaging spectrograph flown to date. RAISE is designed to observe the dynamics and heating of the solar chromosphere and corona on time scales as short as 100–200ms, with arcsecond spatial resolution and a velocity sensitivity of 1–2km/s. Two full spectral passbands over the same one-dimensional spatial field are recorded simultaneously with no scanning of the detectors or grating. The two different spectral bands (first-order 1205–1251Å and 1524–1569Å) are imaged onto two intensified Active Pixel Sensor (APS) detectors whose focal planes are individually adjusted for optimized performance. RAISE reads out the full field of both detectors at 5–10Hz, recording up to 1800 complete spectra (per detector) in a single 6-min rocket flight. This opens up a new domain of high time resolution spectral imaging and spectroscopy. RAISE is designed to observe small-scale multithermal dynamics in Active Region (AR) and quiet Sun loops, identify the strength, spectrum and location of high frequency waves in the solar atmosphere, and determine the nature of energy release in the chromospheric network.

The article offers news briefs related to fortification and artillery in Great Britain including the concern of author Margaret Pinsent on the restoration on World War 1 antiaircraft gun, the restoration of World War 1 acoustic mirror, and the presentation of plaque to the Grey Point Fort.