Dr. Sebastian Rabien
Max-Planck Institut für extraterrestrische Physik
Giessenbachstr, 85748 Garching, Germany
phone: +49_89300003277
email: srabien(a)mpe.mpg.de
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Dr. Sebastian Rabien Max-Planck Institut für extraterrestrische Physik Giessenbachstr, 85748 Garching, Germany phone: +49_89300003277 email: srabien(a)mpe.mpg.de |
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The ARGOS project at
the Large Binocular Telescope
The ARGOS project has equipped the Large Binocular Telescope (LBT) in Arizona with a multi laser guide star and adaptive optics facility. It has been designed, built and is currently under commissioning phase by an international consortium assembled out of Institutes from Italy, the United States and Germany, led by MPE and me as principal investigator (PI). ARGOS launches a constellation of six laser guide stars, three above each of LBT's primary mirrors. Detecting the 'Rayleigh' laser guide stars with a gated wavefront sensor, enables us to correct the atmospheric distortions over a wide field of view. Each of the LUCI imagers and spectrographs can thus be fed with sharpened images, allowing a strongly enhanced performance. To the right the LBT can be seen with the ARGOS lasers in operation. More information can be found at: The MPE ARGOS webpages |
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First Images with
ARGOS
To the left a J, H-band composition image of NGC 6384 is shown, taken with laser guide star ground layer adaptive optics correction. The resolution in H-band amounts to ~0.22 arcsec close to the central TT star, and is fairly homogenic over the full field of view. With ARGOS coming online, astronomical observations at LBT can be conducted much faster due to the enhanced image sharpness. |
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First Light Image
with
ARGOS
In late 2014 we have been able to close the adaptive optics loop for the first time on the laser guide stars. First ever an 8.4m telecope has been corrected with a laser based GLAO adaptive optics system. The spatial resolution increase from seeing limited to corrected amounts to 2-3, well in agreement with the calculated expectations. Applying this factor to multi object spectroscopy of high distant objects in the universe, will allow these observations to be carried out at LBT in a fraction of time as required nowadays. |
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In situ cryogenic MOS
mask generation
multi object
spectroscopy allows to measure the spectrum
of many objects in the telescopes field of view at the same time. To
select the objects from which to measure the spectrum, requires a
selector mask in the instrument. Since infrared spectrographs are
operated under vacuum at cryogenic temperatures, mask handling and
exchange is rather complex.
Currently we are developing novel methods for in-situ mask generation. Based on laser ablation of thin films at 77K or thin foil cutting and handling. This will facilitate infrared MOS instrument operation greatly and enable advanced observing programs. |
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| ALFA one of the
first astronomical adaptive optics systems with laser guide star. Being
located at the Calar Alto observatory in Spain, ALFA has been using a
3W cw dye laser to create a laser guide star in the earth sodium
layer. |
PARSEC: the laser
system for the VLT Laser guide star facility. Being developed by ma in
the framework of my PhD thesis, it consisted of a master
laser power amplifier, based on dye technology.
With 5 green lasers pumping the system, it routinely delivered 13W
single
frequency cw laser light at the Sodium D2 transition and has shown a
maximum output power of 24W. The LGSF has been in operation at Paranal
for several years. |
GRAVITY:
combining the light from all four UT telescopes at the VLT
interferometrically allows to adress fundamental scientific
questions.
Gravity will measure the position of flares in the galactic center with
µarcsec precision, thus probing space time in the vicinity of a
super
massive black hole. The image shows 1908nm laser fringes at the
secondary for the path length metrology with nm precission. |