Alfred de Wijn

Design of a Highly Efficient Polychromatic Full-Stokes Polarization Modulator for the CRISP Imaging Spectrometer

Graphic image depicting spectro-polarimetric data
Tuesday, February 2, 2021

In 2014 HAO built a polarimetric modulator for the CRISP instrument on the Swedish 1-m Solar Telescope in La Palma, using the principles of polychromatic modulation previously developed by HAO scientists. This paper discusses the processes by which the modulator was designed, built, and tested.

A Rare Transit of Venus

Graphic image of individual frames from the movie showing Venus' transit

A coronagraph instrument at the Mauna Loa Solar Observatory on Hawai’i is used by a team of two scientists to record the rare transit of Venus across the Sun's corona.

Characterization of Cameras for the COSMO K-Coronagraph

Digital image sensors
Thursday, October 11, 2018

Digital image sensors are ubiquitous in astronomical instrumentation and it is well known that they suffer from issues that must be corrected for data to be scientifically useful.

Alfred de Wijn

Dr. Alfred de Wijn is a Research Engineer in the High Altitude Observatory of NCAR. His main research interest is in observational studies of the solar photosphere, chromosphere, and transition region using various ground-based and space-borne instruments.

ChroMag Optics Testing

The Chromospheric and Prominence Magnetometer (ChroMag) prototype optics under test on a lab bench at HAO. Monochromatic green light is being passed through 88mm of calcite. This is the thickest stage in ChroMag. The fringes are used to test the alignment of the optical elements and the crystal axes. ChroMag is one of the planned suite of three instruments of HAO’s Coronal Magnetism Solar Observatory (COSMO), and will be used for solar physics research and space weather applications.

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