Physics – Optics
Scientific paper
Nov 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993a%26a...278l..35r&link_type=abstract
Astronomy and Astrophysics (ISSN 0004-6361), vol. 278, no. 2, p. L35-L38
Physics
Optics
Aluminum Alloys, Geometrical Optics, Machining, Mirrors, Telescopes, Mosaics, Performance Tests
Scientific paper
To investigate the feasibility of large size aluminum mirrors, studies have been undertaken in cooperation with European Southern Observatory (ESO), in the framework of a European program. The first phase, which is just now ended, addressed the following items: (1) tests to select the best aluminum alloy, (2) aluminum welding, homogeneity and stability, (3) aluminum high-precision machining, (4) nickel coating, (5) polishing of the nickel layer, (6) active optics. Furthermore, tests have been conducted to demonstrate that the quality of the mirrors is not altered at various temperatures and after a large number of aluminizing and cleaning cycles (corresponding to about 50 years' life). The mirror shape (whose specifications are fully compliant with those of the Very Large Telescope (VLT), as the program is conducted in cooperation with ESO) was computed under several causes of deformations: evidencing gravity as the predominant effect, and very low distortions as the high thermal conductivity limits the thermal transverse gradient to 0.025 C. Results show that it is quite possible to obtain high optical quality mirrors, mainly due to recent progress both in metallurgical processes (high precision machining -7 microns rms-) and active optics, that permit to correct residual aberrations of the surface. Such an alternative to classical glass mirrors will presently stand as a safe, economical solution that saves manufacturing time, for monolithic or segmented mirrors for innovative telescopes (e.g., lunar interferometric network).
No associations
LandOfFree
First results obtained within the European 'LAMA' programme (Large Active Mirrors in Aluminium) does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with First results obtained within the European 'LAMA' programme (Large Active Mirrors in Aluminium), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and First results obtained within the European 'LAMA' programme (Large Active Mirrors in Aluminium) will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-807267