A comparison of exposure meter systems for three exoplanet-hunting spectrometers: Hamilton, HIRES and APF

R. I. Kibrick; D. A. Clarke; W. T. S. Deich; D. Tucker

doi:10.1117/12.672048

27 June 2006 A comparison of exposure meter systems for three exoplanet-hunting spectrometers: Hamilton, HIRES and APF

R. I. Kibrick, D. A. Clarke, W. T. S. Deich, D. Tucker

Proceedings Volume 6274, Advanced Software and Control for Astronomy; 62741U (2006) https://doi.org/10.1117/12.672048
Event: SPIE Astronomical Telescopes + Instrumentation, 2006, Orlando, Florida , United States

Abstract

The majority of extra-solar planets discovered to date have been found using Doppler-shift measurements obtained with the Hamilton Spectrometer at Lick Observatory and the High Resolution Echelle Spectrometer (HIRES) at Keck Observatory. Each of these spectrometers employs an integral exposure meter which enables observers to optimize exposure times so as to achieve the required signal-to-noise and to determine the photon-weighted midpoint of each science exposure (which is needed to correct the Doppler shift to the Solar System barycenter). In both of these systems, a propeller mirror located behind the spectrometer slit picks off a few percent of the light and directs it to a photo-multiplier tube (PMT) used to measure the exposure level versus time. In late 2006, the new Automated Planet Finder (APF) Telescope and APF Spectrometer are scheduled to begin operations at Lick Observatory; both will be dedicated exclusively to the search for extra-solar planets. Like the Hamilton and HIRES Spectrometers, the APF Spectrometer will employ an integral exposure meter, but one with a significantly different design. The APF exposure meter will employ a stationary pellicle located ahead of the slit to pick off 4% of the light and direct it to the guide camera. That camera will produce images typically at a 1 Hz rate, and those images will be used both for autoguiding and for computing the exposure level delivered to the spectrometer. In each guide camera image obtained during a science exposure, the time-tagged signal from the pixels that correspond to the spectrometer slit will be integrated in software to determine the current exposure level and the photon-weighted midpoint of that science exposure. We compare these two different design approaches, and describe the significant hardware and software features of each of these systems.

Citation Download Citation

R. I. Kibrick, D. A. Clarke, W. T. S. Deich, and D. Tucker "A comparison of exposure meter systems for three exoplanet-hunting spectrometers: Hamilton, HIRES and APF", Proc. SPIE 6274, Advanced Software and Control for Astronomy, 62741U (27 June 2006); https://doi.org/10.1117/12.672048

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available