HIAC
Prototype Instruments
Another central component of CSAC is the development of the next generation of spectro-polarimetric instruments for solar observation and not just in the photosphere, but also the chromosphere and corona. This page provides some information and progress updates the SP instruments being developed at HAO.
The Prominence Magnetometer (ProMag)
 | The Prominence Magnetometer (ProMag) is a spectro-polarimeter soon to be deployed at the Evans Solar Facility of the NSO/Sacramento Peak. It is mainly conceived to do spectro-polarimetry of the chromosphere (in particular prominences and filaments) simultaneously in the HeI lines at 587.6 nm (D3) and 1083.0 nm, but it can also be used to observe the corona in the forbidden emission lines of FeXIII at 1micron. ProMag is designed to achieve a spatial resolution of 2 arcsec and a spectral resolution of 50 mA, at 587.6 nm. |
The instrument consists of a polarimeter placed at F1 of the 40-cm Evans coronagraph, and of a grating spectrograph placed on the East bench of the Evans facility. The polarimeter consists of an FeLC-based achromatic modulator (implementing two Pancharatnam plates) that allows for efficient modulation at the above wavelengths (as well as at intermediate spectral ranges, like H-alpha and the CaII IR triplet). A Wollaston-based beam-splitter is adopted as analyzer. The spectrograph consists of an image rotator, a slit assembly, and a dispersion grating. The function of the image rotator is to keep the separation arrow of the two beams from the polarimeter always aligned with the slit. The polarimeter can also be rotated to align the slit to any given direction on the solar disk. The mapping of a solar structure is performed by translating the slit on the image plane.
| The spectrograph has one visible and one IR channel. The order selection of the grating was optimized for the simultaneous observation of the two HeI lines. However H-alpha and HeI 1083.0 can also be observed simultaneously, with only minor vignetting. The detectors are a Pluto camera for the visible range, and an IR Rockwell camera borrowed from the Coronal Multi-channel Polarimeter, during periods of downtime of the latter instrument. At this time, we are in the process of acquiring a dedicated IR camera for ProMag. |  |
A paper on ProMag (PDF) can be found here.
FOR MORE INFORMATION VISIT:
ProMag Site at HAO
Current Status: Being deployed at NSO/DST.
Spectro-Polarimeter for Infrared and Optical Regions (SPINOR)
 | 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.). |
A paper describing the details of SPINOR (PDF) can be found here.
FOR MORE INFORMATION VISIT:
SPINOR Site at HAO
SPINOR User's Calibration Manual (PDF)
SPINOR Configurator Manual (PDF)
Current Status: Operational, Deployed at NSO/DST.
Coronal Multi-channel Polarimeter (CoMP)
 | While CoMP was not built with CSAC funds, its revolutionary observations of Stokes polarization in the corona and the ability to make inversions of the coronal magnetic field do fall into the realm of CSAC. The CoMP instrument is a combination polarimeter and narrowband tunable filter that can measure the complete polarization state in the vicinity of the 1074.7 and 1079.8nm FeXIII coronal emission lines and the 1083.0 nm HeI chromospheric line. It was deployed behind the 20-cm aperture Coronal One Shot (COS) coronagraph on the equatorial spar of the Hilltop facility at the Sacramento Peak Observatory of the National Solar Observatory in New Mexico. CoMP is comprised of: 1) an occulting disk, located at the focus of the COS, that blocks the light from the solar disk; 2) a lens that collimates the solar image; 3) a filter wheel holding three order-blocking filters corresponding to each of the three observable emission line regions; 4) the polarimeter/tunable filter package; 5) a re-imaging lens that forms the final solar image; and 6) a 1024x1024 pixel HgCdTe infrared detector array. |
The CoMP polarimeter is formed by a pair of Liquid Crystal Variable Retarders (LCVRs) followed by a linear polarizer that allows the selection of a polarization state parameterized by a Stokes vector [I, Q, U, V], where I is the intensity, Q and U describe net linear polarization states and V describes the net circular polarization. The CoMP polarimeter selects a Stokes state I+/-S where S is Q, U, or V. The CoMP filter is a four-stage, wide-field calcite birefringent filter with a bandwidth of 0.13 nm. It is tuned in wavelength by four additional LCVRs. The final element of the filter is a Wollaston prism, which splits the beam into emission line and continuum bandpasses. The line and continuum image pair is focused simultaneously onto the detector along the diagonal with a full field of view of 2.8 solar radii (Rsun) at a spatial sampling of 4.5 arcseconds/pixel.
A paper describing the details of CoMP (PDF) can be found here.
FOR MORE INFORMATION VISIT:
CoMP Site at HAO
CoMP Finds Alfven Waves in the Solar Atmosphere
Current Status: Being moved to HSO (UH, Maui).