Speckle Imaging with VLT/NACO No-AO Mode

TL;DR

This paper demonstrates the use of speckle imaging with VLT/NACO's no-AO mode to achieve high-resolution images in the J-band, offering an effective alternative to adaptive optics under suboptimal conditions.

Contribution

It introduces the application of speckle imaging with NACO's no-AO mode at the VLT, highlighting its effectiveness in high-resolution imaging without adaptive optics.

Findings

Speckle imaging with no-AO mode achieves diffraction-limited resolution.

Effective in J-band under mediocre observing conditions.

Versatile for imaging extended objects.

Abstract

Long-exposure stellar images recorded with large ground-based telescopes are blurred due to the turbulent nature of the atmosphere. The VLT employs active and adaptive optics (AO) systems to compensate for the deleterious effects of the atmosphere in real time. The speckle imaging technique provides an alternative way to achieve diffraction-limited imaging by post-processing a series of short-exposure images. The use of speckle imaging with the no-AO mode of NACO at the VLT is demonstrated. Application of this technique is particularly suited to the J-band and it provides versatile high angular resolution imaging under mediocre conditions and/or in imaging extended objects. The implementation of this mode underlines the continuing attractiveness of NACO at the VLT.