First-light instrument for the 3.6m DOT: 4Kx4K CCD Imager

TL;DR

The paper describes the design, development, and deployment of a 4Kx4K CCD imager as the first-light instrument for the 3.6m DOT, enabling deep multi-band optical imaging for various astronomical research goals.

Contribution

It introduces the first-light 4Kx4K CCD imager for the 3.6m DOT, detailing its design, testing, and deployment for deep optical imaging in multiple science applications.

Findings

Successfully mounted and tested at the 3.6m DOT in 2016.

Enables deep multi-band imaging for diverse astronomical studies.

Supports observations of cosmic transients, active galaxies, and more.

Abstract

As an in-house instrument developmental activity at ARIES, the 4Kx4K CCD Imager is designed and developed as a first-light instrument for the axial port of the 3.6m DOT. The f/9 beam of the telescope having a plate-scale of ~ 6.4 arc-sec/mm is utilized to conduct deeper photometry within the central 10 arc-min field of view. The pixel size of the blue-enhanced liquid Nitrogen cooled STA4150 4Kx4K CCD chip is 15 micron, with options to select gain and speed values to utilize the dynamic range. Using the Imager, it is planned to image the central ~ 6.5x6.5 arc-min^2 field of view of the telescope for various science goals by getting deeper images in several broad-band filters for point sources and objects with low surface brightness. The fully assembled Imager along with automated filter wheels having Bessel UBVRI and SDSS ugriz filters was tested in late 2015 at the axial port of the 3.6m DOT. This instrument was finally mounted at the axial port of the 3.6m DOT on 30th March 2016 when the telescope was technically activated jointly by the Prime Ministers of India and Belgium. This instrument is expected to serve as a general purpose multi-band deep imaging instrument for variety of science goals including studies of cosmic transients, active galaxies, star clusters and optical monitoring of X-ray sources discovered by the newly launched Indian space-mission called ASTROSAT and follow-up of radio bright objects discovered by the GMRT.