Telescope snaps asteroid image

05 Sep 2002

Observers take the first image of a near-Earth asteroid with an adaptive optics system.

Near-Earth asteroid

Astronomers at the William Herschel Telescope (WHT) in the Canary Islands have released what they claim is 'the first image of a near-Earth asteroid obtained with an adaptive optics system'. The image was taken with the NAOMI camera, which is installed on the 4.2 meter telescope.

An adaptive optics system uses fast-moving mirrors to correct for atmospheric distortion in real-time. This allows ground-based astronomers to acquire images with resolution equal or exceeding that of space-based telescopes such as Hubble.

The image was taken in the infrared at a wavelength of 1.63 microns, the so-called H-band, and has a resolution 0.11 arcseconds. The team says this is close to the theoretical limit of the telescope.

Night vision

During the observations made between August 17 to 18 this year, the near-Earth asteroid, named 2002 NY40, came within 750 000 kilometers of Earth - just twice the distance to the Moon.

The WHT is part of the Isaac Newton group (ING) of telescopes run by a collaboration of researchers in the United Kingdom, the Netherlands and Spain.

Author
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.