Denny Kaniela Dement is a junior at the University of Hawai’i at Hilo majoring in Astronomy. He enjoys camping, hiking, reading, and any water sports, especially surfing. His interest in astronomy comes from the spirit of discovery, unveiling the secrets of the Universe for the benefit of all.

Institution when acceptedUniversity of Hawai’i at Hilo

Akamai Project:  Analysis of Atmospheric Differential Refraction on OSIRIS Infrared Spectra

Project Site:  W.M. Keck Observatory

Mentors:  Bob Goodrich and Randy Campbell

Project Abstract: 

At night, light from outer space becomes “speckled” because of the Earth’s turbulent atmosphere. High atop Mauna Kea (Big Island, Hawaii), the 10m-diameter Keck II telescope’s Laser-Guide Star Adaptive Optics (LGSAO) is capable of recombining the light back into focus. However, when using OSIRIS (OH-Suppressing Infra-Red Imaging Spectrograph) at Keck II, LGSAO cannot correct for Atmospheric Differential Refraction (ADR). ADR corrupts OSIRIS spectra. The aim of this project is to analyze how ADR is affecting the XY shifts of stars as they travel through an OSIRIS “data cube.” This analysis will be useful in creating software to correct for these shifts, improving the quality of spectra. “Data cube” refers to recombining spectra data into 3-D images. The dimensions are pixel spectra (XY) and last wavelength (Z). A Gaussian fit routine in UCLA’s Quick Look 2 Interactive Data Language (IDL) software calculates XY centroids. These centroids were used to create a model of how far a star moves in acrseconds vs. wavelength. A combination of equations from Peck & Reeder (1972) and Roe (2002) was employed in finalizing the model. The result of the measured vs. calculated shifts reveals a separation of 7 milli-arcseconds. In the future, this data will be applied to write a new IDL module to add to the data reduction pipeline.

Link to PDF of Kaniela’s project presentation.