Mars in the Infrared - observed while only 57,000,000 km away!

The above image of Mars was obtained on Aug 17th 2003 when Mars was at a distance of 57 million km from Earth and had an apparent diameter of 24.6 arc seconds. The observers were Jeremy Bailey and Sarah Chamberlain (Anglo-Australian Observatory and Australian Centre for Astrobiology, Macquarie University).

The image was obtained with UIST and is a composite of three narrow band filters at wavelengths of 1.57, 1.64 and 2.12 micrometres in the near Infrared. The dark markings resemble those seen at visible wavelengths, but the south polar cap (at the bottom of the picture) is less prominent as its ice absorbs at infrared wavelengths. The slight green colour around the polar cap is a result of ice absorption.

The data were obtained as part of a UKIRT programme of imaging and spectroscopy of the planet. The data will provide information on the mineral composition of the surface and on the gas and dust in the Martian atmosphere.