Instrument | |
Instrument Name: | The Extreme Polarimeter (ExPo) |
Telescope: | William Herschel Telescope (WHT) La Palma |
Telescope Aperture: | 4.2 m |
Telescope Port: | Nasmyth (visiting port) |
Status: | Operational |
Commissioning Date: | 01.10.2008 |
Polarimetry: | |
Polarimetry Type: | Beam-exchange |
Stokes Parameters: | I Q U |
Wavelength Range: | |
Modulator Type: | (FLC) Ferro-electric Liquid Crystal |
Modulator Type Other: | |
Modulation Frequency: | 35 Hz |
Analyzer Type: | Polarizing beamsplitter cube |
Analyzer Type Other: | |
Sensitivity: | 0.0001 |
Accuracy Zero Point: | |
Accuracy Scaling: | |
Imaging: | Yes |
Wavelength Range: | 500-900 nm |
Field of View: | 12'' x 12'' |
Resolution: | Seeing-limited |
Pixel Scale: | 80 mas |
Pixel Dimensions: | 200 x 200 |
Sensor Type: | EMCCD (Andor iXon) |
Limiting Magnitude: | 14 |
Coronograph: | Yes |
Coronograph Type: | Lyot |
Coronograph IWA: | ~1'' |
Adaptive Optics: | No |
DM, Number of Actuators: | |
DM Type: | |
WFS Type: | |
WFS Update frequency: | |
Strehl: | |
Limiting Magnitude: | |
Spectroscopy: | No |
Sampling: | |
Wavelength Range: | |
Spectral Resolution: | |
Limiting Magnitude: | |
Instrument Image: | 513a0aa456722-fig1.pdf |
Instrument Image Caption: | The ExPo instrument as installed at the Nasmyth visiting instrument focus of the William Herschel Telescope. |
Instrument Reference Paper: | Rodenhuis et al. 2012 (Proc. SPIE) http://adsabs.harvard.edu/abs/2012SPIE.8446E..9IR |
Known Issues: | |
Instrument Contact: | Michiel Rodenhuis (rodenhuis@strw.leidenuinv.nl) |
Instrument Website: | |
Planned Upgrades: | Adaptive optics system, Spectro-polarimetric IFU |
Science | |
Science Description: | Scattering polarization from dust in circumstellar environments: Protoplanetry disks, debris disks, dust envelopes around evolved stars. |
Target Types: | Herbig Ae/Be, Post-AGB, Solar System |
Sample Image/Result: | 513f2fd11daf1--fig2.eps |
Sample image Caption: | ExPo linear polarization image of T Tauri. Image measures 12 x 12 arcseconds across. The degree of linear polarization is shown on a logarithmic (red-yellow-white) intensity scale between 10^-2 and 10^-4. Blue vectors trace the polarization direction. |
Sample Science Papers: | http://adsabs.harvard.edu/abs/2012A%26A...543A..70C http://adsabs.harvard.edu/abs/2012A%26A...539A..56J http://adsabs.harvard.edu/abs/2011ASPC..448...15J |
Remarks: |