The problem of making rigid telescope mirrors

Telescope mirrors need to be very stiff so that the optical shape of their surfaces is close to perfect to create sharp images. Unfortunately this means that rigid mirrors without active support have to be very thick, and hence very heavy and hard to support, if they are to be adequately stiff. This problem led to the development of thin mirrors with active support, first for the NTT and later the VLT.


ESO/L. Calçada

About the Video

Release date:2 September 2015, 13:20
Duration:16 s
Frame rate:30 fps

About the Object

Name:Extremely Large Telescope
Type:Unspecified : Technology : Observatory : Telescope



Large QT
4.6 MB


Video Podcast
3.4 MB
Medium MPEG-1
8.8 MB
Medium Flash
3.7 MB

For Broadcasters