Extreme precision photometry from the ground with beam-shaping diffusers for K2, TESS, and beyond

Gudmundur Stefansson; Suvrath Mahadevan; John Wisniewski; Yiting Li; Leslie Hebb; Brett Morris; Samuel Halverson; Andrew Monson; Paul Robertson

doi:10.1117/12.2312833

2 August 2018 Extreme precision photometry from the ground with beam-shaping diffusers for K2, TESS, and beyond

Gudmundur Stefansson, Suvrath Mahadevan, John Wisniewski, Yiting Li, Leslie Hebb, Brett Morris, Samuel Halverson, Andrew Monson, Paul Robertson

Author Affiliations +

Proceedings Volume 10702, Ground-based and Airborne Instrumentation for Astronomy VII; 1070250 (2018) https://doi.org/10.1117/12.2312833
Event: SPIE Astronomical Telescopes + Instrumentation, 2018, Austin, Texas, United States

Abstract

The Transiting Exoplanet Survey Satellite (TESS, launched early 2018) is expected to find a multitude of new transiting planet candidates around the nearest and brightest stars. Timely high-precision follow-up observations from the ground are essential in confirming and further characterizing the planet candidates that TESS will find. However, achieving extreme photometric precisions from the ground is challenging, as ground-based telescopes are subject to numerous deleterious atmospheric effects. Beam-shaping diffusers are emerging as a low-cost technology to achieve hitherto unachievable differential photometric precisions from the ground. These diffusers mold the focal plane image of a star into a broad and stable top-hat shape, minimizing photometric errors due to non-uniform pixel response, atmospheric seeing effects, imperfect guiding, and telescope-induced variable aberrations seen in defocusing. In this paper, we expand on our previous work (Stefansson et al. 2017; Stefansson et al. 2018), providing a further detailed discussion of key guidelines when sizing a diffuser for use on a telescope. Furthermore, we present our open source Python package iDiffuse which can calculate the expected PSF size of a diffuser in a telescope system, along with its expected on-sky diffuser-assisted photometric precision for a host star of a given magnitude. We use iDiffuse to show that most (~80%) of the planet hosts that TESS will find will be scintillation limited in transit observations from the ground. Although iDiffuse has primarily been developed to plan challenging transit observations using the diffuser on the ARCTIC imager on the ARC 3.5m Telescope at Apache Point observatory, iDiffuse is modular and can be easily extended to calculate the expected diffuser-assisted photometric precisions on other telescopes.

Citation Download Citation

Gudmundur Stefansson, Suvrath Mahadevan, John Wisniewski, Yiting Li, Leslie Hebb, Brett Morris, Samuel Halverson, Andrew Monson, and Paul Robertson "Extreme precision photometry from the ground with beam-shaping diffusers for K2, TESS, and beyond", Proc. SPIE 10702, Ground-based and Airborne Instrumentation for Astronomy VII, 1070250 (2 August 2018); https://doi.org/10.1117/12.2312833

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