CFHTLS interactive image gallery

The Deep and Wide survey images of the Canada-France-Hawaii-Telescope Legacy Survey (CFHTLS) cover more than 170 square degrees of sky in 5 bands, from the near-UV to the near-InfraRed. The Wide survey reaches r~25 mag while the Deep goes one magnitude deeper. Thanks to the combination of an exceptional observing site and the excellent image quality delivered by the MegaPrime instrument, images are very sharp: the  typical seeing Full Width at Half-Maximum is 0.7 arcsecond, down to 0.5 arcsecond in some fields.

The shear size of the survey, and the fact that it has been deliberately placed in sky regions devoid of any truly bright, spectacular object, make it difficult to appreciate the wealth of information it carries for the non-specialist.  Posters cannot do justice to such large and detailed images, unless they are printed in gigantic proportions.

STIFF 2.0 brings the possibility of creating image pyramids out of arbitrary large FITS files. The concept of image pyramids is used in web applications such as Google Maps to allow users to explore extremely detailed pictures in an interactive way. To create the zoomable CFHTLS  colour images below, stacked images of the T06 TERAPIX release were stitched together using SWarp, and converted to tiled pyramidal BigTIFF format with STIFF 2.0. Images are served using the IIPImage streaming client/server software. The largest image is 87417×76550 pixels!  Tune up your display and enjoy the scenery!

CFHTLS-Deep:

• D1 1°×1° field at α=02^h26^m00^s, δ=-04°30’00” (in W1)
• D2 1°×1° field at α=10^h00^m20^s, δ=+02°12’21” (COSMOS/ACS survey field)
• D3 1°×1° field at α=14^h17^m54^s, δ=+52°30’31” (in W3)
• D4 1°×1° field at α=22^h15^m31^s, δ=-17°44’05” (around quasar LBQS2212-17)

• W1 8°×9° field at α=02^h18^m00^s, δ=-07°00’00” (XMM LSS field)
• W2 7°×7° field at α=08^h54^m00^s, δ=-04°15’00”
• W3 7°×7° field at α=14^h17^m54^s, δ=+54°30’31” (Groth Strip)
• W4 4°×4° field at α=22^h13^m18^s, δ=+01°19’00” (VVDS 22h & UKIDSS DXS fields)

Acknowledgements