Camera for QUasars in EArly uNiverse (CQUEAN)

TL;DR

CQUEAN is an optical CCD camera designed for efficient follow-up imaging of red sources like high-redshift quasars, Gamma Ray Bursts, and brown dwarfs, with high quantum efficiency and reliable performance since 2010.

Contribution

The paper introduces CQUEAN, a specialized camera system optimized for red source observations, developed rapidly and demonstrating high efficiency and stability in the early universe research.

Findings

Achieves stable guiding in 20-minute exposures

Provides imaging quality with FWHM >= 0.6" over the entire field

Reaches a limiting magnitude of z=23.4 AB mag in one hour

Abstract

We describe the overall characteristics and the performance of an optical CCD camera system, Camera for QUasars in EArly uNiverse (CQUEAN), which is being used at the 2.1 m Otto Struve Telescope of the McDonald Observatory since 2010 August. CQUEAN was developed for follow-up imaging observations of red sources such as high redshift quasar candidates (z >= 5), Gamma Ray Bursts, brown dwarfs, and young stellar objects. For efficient observations of the red objects, CQUEAN has a science camera with a deep depletion CCD chip which boasts a higher quantum efficiency at 0.7 - 1.1 um than conventional CCD chips. The camera was developed in a short time scale (~ one year), and has been working reliably. By employing an auto-guiding system and a focal reducer to enhance the field of view on the classical Cassegrain focus, we achieve a stable guiding in 20 minute exposures, an imaging quality with FWHM >= 0.6" over the whole field (4.8' * 4.8'), and a limiting magnitude of z = 23.4 AB mag at 5-sigma with one hour total integration time.