Diffraction-limited spectropolarimeter: Phase I

Sankarasubramanian, K.; Elmore, D.; Lites, B. W.; Sigwarth, M.; Rimmelé, Thomas; Hegwer, S.; Gregory, Scott; Streander, K. V.; Wilkins, Lawrence M.; Richards, Kit; Berst, Chris

doi:10.1117/12.459281

Cited by 17 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the second fit only data from 2002 through 2005 were used and the resulting slope was 47 G yr Ϫ1 . Recent high-resolution magnetic field observations of sunspot umbral bright points show a reduction of the magnetic field strength in the bright points (Sankarasubramanian et al 2004). It is possible that during the observing period the average number of umbral bright points increased and produced the mag-netic field drop that we observe, although Maltby et al (1986) shows that for thermal reasons the umbral intensity increase could not be explained by an increased number of umbral dots.…”

Section: Discussionmentioning

confidence: 53%

Temporal Changes in Sunspot Umbral Magnetic Fields and Temperatures

Penn

Livingston

2006

ApJ

101

View full text Add to dashboard Cite

We have observed high-resolution intensity spectra near the Fe i 1564.8 nm line at a single umbral point corresponding to the darkest position in over 900 sunspots from 1998 through 2005. From these data we determine that the maximum sunspot magnetic fields have been decreasing at about 52 G yr Ϫ1. The same data set shows a concurrent increase in the normalized umbral intensity from 0.60 to 0.75 (corresponding to a blackbody temperature rise from 5137 to 5719 K) and a decrease of more than 50% in the molecular OH line strength. The magnetic field and intensity changes observed over time in the sunspot umbrae from different spots behave in the same way as the magnetic field and intensity changes observed spatially across single sunspots.

show abstract

Section: Discussionmentioning

confidence: 53%

Temporal Changes in Sunspot Umbral Magnetic Fields and Temperatures

Penn

Livingston

2006

ApJ

101

View full text Add to dashboard Cite

show abstract

“…magnitude and orientation of the field, with high precision, using a vector-polarimeter. A number of these instruments are presently operated at several solar observatories, e.g., the Advanced Stokes Polarimeter (Skumanich et al 1997) and the Diffraction-Limited Stokes Polarimeter (Sankarasubramanian et al 2003) at the Dunn Solar Telescope of the National Solar Observatory, the ZIMPOL-instruments (Gandorfer & Povel 1997;Gandorfer et al 2004) that have been used at different telescopes, the Tenerife Infrared Polarimeter (TIP) (Martínez Pillet et al 1999) at the German Vacuum Tower Telescope (VTT), the spectro-polarimetric mode of the THEMIS solar Appendices are only available in electronic form at http://www.edpsciences.org…”

Section: Introductionmentioning

confidence: 99%

Polarimetric Littrow Spectrograph – instrument calibration and first measurements

Beck¹,

Schmidt²,

Kentischer³

et al. 2005

A&A

110

128

View full text Add to dashboard Cite

Abstract. We present first measurements and the calibration procedure for the Polarimetric Littrow Spectrograph (POLIS) operated at the Vacuum Tower Telescope on Tenerife, together with a brief summary of the technical characteristics of the instrument. In its present configuration, we achieve a polarimetric accuracy of about 3 × 10 −3 in the visible channel (630 nm) of the instrument. The accuracy is limited by cross talk among the different polarization states. The detection limit for polarized light is about 2 × 10 −3 for a 7 s exposure. Polarimetric measurements in the blue channel (Ca  H line, 396.7 nm) are strongly limited by the low photon flux. At this wavelength we present Stokes-V maps with a spatial resolution of about 0.5 arcs. The polarimetric quality of any spectropolarimeter is limited by the precision of the instrument calibration. We present a new method for self-calibration that reduces cross talk among the polarization components to 0.1%. This improvement results from a measurement of the retardance of the calibration waveplate with an accuracy of 0.1• . We demonstrate the capability of the simultaneous use of POLIS and the Tenerife Infrared Polarimeter which is integrated in the main spectrograph of the Vacuum Tower Telescope.

show abstract

“…The main post focus instrument fed by the high order AO is the newly developed Diffraction Limited SpectroPolarimeter, which had it's first and very successful engineering run in March, 2002 at the DST. 10 Light from the telescope enters the optical bench from below through a hole in the bench. Mounted to the bottom of the bench is the DLSP calibration package, which holds a set of motorized polarizers and retarders used to calibrate the polarimeter.…”

Section: Optical Setupmentioning

confidence: 99%

Solar adaptive optics: a progress report

et al. 2003

Self Cite

View full text Add to dashboard Cite

We present a progress report of the solar adaptive optics (AO) development program at the National Solar Observatory (NSO) and the Big Bear Solar Observatory (BBSO). Examples of diffraction-limited observations obtained with the NSO low-order solar adaptive optics system at the Dunn Solar Telescope (DST) are presented. The design of the high order adaptive optics systems that will be deployed at the DST and the BBSO is discussed. The high order systems will provide diffraction-limited observations of the Sun in median seeing conditions at both sites.

show abstract

Diffraction-limited spectropolarimeter: Phase I

Cited by 17 publications

References 0 publications

Temporal Changes in Sunspot Umbral Magnetic Fields and Temperatures

Temporal Changes in Sunspot Umbral Magnetic Fields and Temperatures

Polarimetric Littrow Spectrograph – instrument calibration and first measurements

Solar adaptive optics: a progress report

Contact Info

Product

Resources

About