Daily Image
05-11-2010
LED works at 40K
| Submitter: | Eddy Elswijk |
| Description: | No scientific breakthrough, no technical novelty but still an essential result. For the cryogenic alignment of MATISSE with respect to the warm optics, not many fiducial landmarks are available. The optical axis of each of the four beams per cryostat � MATISSE has a cryostat for the LM and one for the N-band � is defined by the cold stop and a pinhole. The cold stop is visible since it has deliberately applied orthogonal scratches which return reflected light in a diffuse way. The pinhole is only visible when it is illuminated from the back. And that�s where the LED kicks in. The N-band cryostat runs at 40 K (LM-band at 80 K) and therefore we consider ourselves lucky that a LED works at 40 K. The only remark is that we needed 5 V in the cold instead of 2 V at room temperature. What we see in the picture are the 2 LED�s, seen through the window of the test cryostat. Further, a Tip-Tilt Mirror (upper left), a Piezo Motor and two Mirror clips (Bottom) are tested in one cool down run. MATISSE will be a mid-infrared spectro-interferometer combining the beams of up to four telescopes of the ESO VLTI, providing phase closure and image reconstruction. Matisse will produce interferometric spectra in the LM and in the N band (2.3 to 13.5 micron) and is as such a successor of MIDI. The instrument will be developed by a consortium consisting of Observatoire de Nice (warm optics), NOVA Opt/IR group at ASTRON (cold optics), MPI-A (cryostats) and MPIfR (detectors). |
| Copyright: | NOVA |
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