Sir — We would like to correct a misleading impression left by your News article on the new Green Bank Telescope (GBT) ( Nature 406, 816: 2000), which achieved first light on 22 August 2000. Funding for the GBT was appropriated by Senator Robert Byrd (Democrat, West Virginia) not with an earmark, but with a $75 million addition to the already established 1989 NSF budget.
While it is true, as your reporter wrote, that the project has taken considerably longer than initially planned, the telescope is not “tens of millions of dollars over budget”, as it was built under a fixed-price contract. It is correct that claims by the contractor seeking additional payment are in arbitration, but your story appears to anticipate the arbitrator's decision while the hearing is still in progress.
More important, though, your article leaves the impression that the GBT stands alone as the “last of the giants”, and that use of large single dishes is being superseded by other approaches.
On the contrary, there has been a resurgence in the use of single-dish telescopes, stimulated in part by astronomical discoveries, but also by the development of active reflecting surface technology and focal-plane array detectors. As well as the GBT, large single-dish telescopes are under construction in Sardinia and Mexico and one is planned in China. Major upgrades have been undertaken to instruments in Puerto Rico, France, Germany and the United Kingdom. Single-dish telescopes are a critical component of world astronomical capability.