Integration and testing of the GRAVITY infrared camera for multiple telescope optical beam analysis

• Type: Article in International Conference Proceedings Book
• Date: 2014

Authors

Gordo, P (Author) Other; Amorim, A (Author) Other; Abreu, J (Author) Other; Eisenhauer, F (Author) Other; Anugu, N (Author) Other; P. J. V. Garcia (Author) FEUP; Pfuhl, O (Author) Other; Haug, M (Author) Other; Sturm, E (Author) Other; Wieprecht, E (Author) Other; Perrin, G (Author) Other; Brandner, W (Author) Other; Straubmeier, C (Author) Other; Perraut, K (Author) Other; Duarte Naia, MD (Author) Other; Guimaraes, M (Author) Other

Conference proceedings International

Title: OPTICAL AND INFRARED INTERFEROMETRY IV

Conference on Optical and Infrared Interferometry IV

Montreal, CANADA, JUN 23-27, 2014

Indexing

ISI Web of Knowledge - 1 Citation

Scopus - 4 Citations

Other information

Authenticus ID: P-00G-1ED

DOI: 10.1117/12.2056572

Abstract (EN): The GRAVITY Acquisition Camera was designed to monitor and evaluate the optical beam properties of the four ESO/VLT telescopes simultaneously. The data is used as part of the GRAVITY beam stabilization strategy. Internally the Acquisition Camera has four channels each with: several relay mirrors, imaging lens, H-band filter, a single custom made silica bulk optics (i.e. Beam Analyzer) and an IR detector (HAWAII2-RG). The camera operates in vacuum with operational temperature of: 240k for the folding optics and enclosure, 100K for the Beam Analyzer optics and 80K for the detector. The beam analysis is carried out by the Beam Analyzer, which is a compact assembly of fused silica prisms and lenses that are glued together into a single optical block. The beam analyzer handles the four telescope beams and splits the light from the field mode into the pupil imager, the aberration sensor and the pupil tracker modes. The complex optical alignment and focusing was carried out first at room temperature with visible light, using an optical theodolite/alignment telescope, cross hairs, beam splitter mirrors and optical path compensator. The alignment was validated at cryogenic temperatures. High Strehl ratios were achieved at the first cooldown. In the paper we present the Acquisition Camera as manufactured, focusing key sub-systems and key technical challenges, the room temperature (with visible light) alignment and first IR images acquired in cryogenic operation.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8