A team of astronomers and engineers from French and German research institutes and ESO at the Paranal Observatory is celebrating the successful accomplishment of "First Light" for the NAOS-CONICA Adaptive Optics facility. With this event, another important milestone for the Very Large Telescope (VLT) project has been passed.
Normally, the achievable image sharpness of a ground-based telescope is limited by the effect of atmospheric turbulence. However, with the Adaptive Optics (AO) technique, this drawback can be overcome and the telescope produces images that are at the theoretical limit, i.e., as sharp as if it were in space.
Adaptive Optics works by means of a computer-controlled, flexible mirror that counteracts the image distortion induced by atmospheric turbulence in real time. The larger the main mirror of the telescope is, and the shorter the wavelength of the observed light, the sharper will be the images recorded.
During a preceding four-week period of hard and concentrated work, the expert team assembled and installed this major astronomical instrument at the 8.2-m VLT YEPUN Unit Telescope (UT4). On November 25, 2001, following careful adjustments of this complex apparatus, a steady stream of photons from a southern star bounced off the computer-controlled deformable mirror inside NAOS and proceeded to form in CONICA the sharpest image produced so far by one of the VLT telescopes.
With a core angular diameter of only 0.07 arcsec, this image is near the theoretical limit possible for a telescope of this size and at the infrared wavelength used for this demonstration (the K-band at 2.2 micron). Subsequent tests reached the spectacular performance of 0.04 arcsec in the J-band (wavelength 1.2 micron).
"I am proud of this impressive achievement", says ESO Director General Catherine Cesarsky. "It shows the true potential of European science and technology and it provides a fine demonstration of the value of international collaboration. ESO and its partner institutes and companies in France and Germany have worked a long time towards this goal - with the first, extremely promising results, we shall soon be able to offer a new and fully tuned instrument to our wide research community."
The NAOS adaptive optics corrector was built, under an ESO contract, by Office National d'Etudes et de Recherches Aerospatiales (ONERA), Laboratoire d'Astrophysique de Grenoble (LAOG) and the DESPA and DASGAL laboratories of the Observatoire de Paris in France, in collaboration with ESO. The CONICA infra-red camera was built, under an ESO contract, by the Max-Planck-Institut fuer Astronomie (MPIA) (Heidelberg) and the Max-Planck Institut fuer Extraterrestrische Physik (MPE) (Garching) in Germany, in collaboration with ESO.
The present event happens less than four weeks after "First Fringes" were achieved for the VLT Interferometer (VLTI) with two of the 8.2-m Unit Telescopes. No wonder that a spirit of great enthusiasm reigns at Paranal!
Information for the media: ESO is producing a Video News Release (ESO Video News Reel No. 13) with sequences from the NAOS-CONICA "First Light" event at Paranal, a computer animation illustrating the principle of adaptive optics in NAOS-CONICA, as well as the first astronomical images obtained. In addition to the usual distribution, this VNR will also be transmitted via satellite Friday 7 December 2001 from 09:00 to 09:15 CET (10:00 to 10:15 UT) on "Europe by Satellite". These video images may be used free of charge by broadcasters. Satellite details, the script and the shotlist will be on-line from 6 December on the ESA TV Service Website http://television.esa.int. Also a pre-view Real Video Stream of the video news release will be available as of that date from this URL.
This Press Release includes the following video and photos:
Video Clip 07/01: Various video scenes related to the NAOS-CONICA "First Light" Event (from ESO Video News Reel No. 13).
PR Photo 33a/01: NAOS-CONICA "First light" image of an 8-mag star.
PR Photo 33b/01: The moment of "First Light" at the YEPUN Control Consoles.
PR Photo 33c/01: Image of NGC 3603 (K-band) area (NAOS-CONICA).
PR Photo 33d/01: Image of NGC 3603 wider field (ISAAC).
PR Photo 33e/01: I-band HST-WFPC2 image of NGC 3603 field.
PR Photo 33f/01: Animated GIF, with NAOS-CONICA (K-band) and HST-WFPC2 (I-band) images of NGC 3603 area.
PR Photo 33g/01: Image of the Becklin-Neugebauer Object.
PR Photo 33h/01: Image of a very close double star.
PR Photo 33i/01: Image of a 17-magnitude reference star.
PR Photo 33j/01: Image of the central area of the 30 Dor star cluster.
PR Photo 33k/01: The top of the Paranal Mountain (November 25, 2001).
PR Photo 33l/01: The NAOS-CONICA instrument attached to VLT YEPUN.
The complete text of ESO PR 25/01 is available at:
http://www.eso.org/outreach/press-rel/pr-2001/pr-25-01.html