DAO Observations and Instrumentation Jason Grunhut

Introduction to the Dominion astrophysical Observatory Situated on the peak of Observatory Hill in Victoria on Vancouver Island, British Columbia. Situated on the peak of Observatory Hill in Victoria on Vancouver Island, British Columbia. 19 th mag dark skies 19 th mag dark skies Two telescopes available Two telescopes available 1.85 m Plaskett 1.85 m Plaskett f/18 Cassegrain focus f/18 Cassegrain focus f/5 modified Newtonian focus f/5 modified Newtonian focus Primarily used for spectroscopy Primarily used for spectroscopy fully automatic pointing and guiding fully automatic pointing and guiding 1.22 m McKeller telescope 1.22 m McKeller telescope Primarily used with Coudé focus. Primarily used with Coudé focus. Used for both spectroscopy and photometry Used for both spectroscopy and photometry

The 72’’ Dome and Telescope

Available Residences

The Polarimeter designed and built by Dmitry Monin made from commercially available products cheap installed immediately after spectrograph slit. achromatic quarter-wave plate converts light into two orthogonal linear polarizations (vertical/horizontal). Ferroelectric Liquid Crystal (FLC) acts as half-wave plate voltage controlled near instantaneous change (few ns). Calcite beam-displacer use to form image on CCD.

The Polarimeter - Continued Take many spectra in two orthogonal states to remove instrumental effects. Take many spectra in two orthogonal states to remove instrumental effects. Best at several Hz level Best at several Hz level Usually use about shifts. Usually use about shifts. Record both orthogonal states simultaneously. Record both orthogonal states simultaneously.

CCD Image Cover Å 0.15 Å/pixel dispersion Resolving power of ~ ~70 G accuracy for 6 th magnitude star in about 20 minutes (emission line star) using Fourier cross-correlation

Problem of Charge Traps

Reductions Reduced and extracted using IRAF Reduced and extracted using IRAF Correct for bias and bad pixels Correct for bias and bad pixels Each beam is extracted separately Each beam is extracted separately Matching beams are then combined Matching beams are then combined Single wavelength calibration is then applied Single wavelength calibration is then applied Stokes V is simply calculated from the difference of the two spectra (no prior normalization) Stokes V is simply calculated from the difference of the two spectra (no prior normalization) Resulting Stokes V and I spectra are normalized. Resulting Stokes V and I spectra are normalized.

Results: 53 Cam

Normalized Spectra: 53 Cam

Normalized Spectra: HD215441

Field Measurement Comparisons: 53 Cam

Field Measurement Comparison: HD71866

Field Measurement Comparison: Theta Aur

Field Measurement Comparison: HD32633

Field Measurement Comparison: HD10221

Issues and Future Spurious detections in null-field standard stars. Spurious detections in null-field standard stars. Procyon, Theta Cep, Sigma And Procyon, Theta Cep, Sigma And Likely due to poor guiding in Declination. Likely due to poor guiding in Declination. Possibly due to poor alignment of crystal. Possibly due to poor alignment of crystal. Improved since first tests. Improved since first tests. Regression routine not entirely suitable as lines are well resolved. Regression routine not entirely suitable as lines are well resolved. Use Fourier Cross-Correlation Use Fourier Cross-Correlation Use LSD method Use LSD method

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Beautiful Victoria