Astronomical Research with liquid mirror telescopes.pdf

a s t r o - p h / 9 7 0 6 1 0 8 1 1 J u n 1 9 9 7 1 Astronomical Research with liquid mirror telescopes Ermanno F. Borra, Centre dOptique, Photonique et Laser, Observatoire du Mont Mégantic, Département de Physique, Université Laval, Canada G1K 7P4 http://wood.phy.ulaval.ca/lmt/home.html Fax: 418-656-2040: Email: borra@phy.ulaval.ca ABSTRACT I discuss the modalities of zenith observing with LMTs, their limitations and advantages. The main limitation comes from the relatively small regions of the sky that LMTs can access. The main advantage comes from low cost, for inexpensive large LMTs can be dedicated to very specialized goals. Large surveys, cosmological studies, variability studies are prime examples of astronomical research where LMTs can have a major impact. I examine the performance of a 4-m telescope equipped with wide band filters and its use for astronomical research. The data could be used to select targets for the VLT. I examine the usage of the data for variability studies and, in particular, for a supernova search. 1. INTRODUCTION Liquid mirrors are a new technology that has begun to demonstrate a performance that is interesting to astronomy. As discussed in my earlier presentation , and by others, in these proceedings, liquid mirrors have been demonstrated in the laboratory (up to 2.5-m diameters) and on the sky (up to 3-m diameters). There is therefore a window of opportunity in which one can do what has never been done before in Astronomy: dedicate a 4-m class telescope to a full time project. This is rendered possible by the low cost of LMTs. A fully instrumented 4-m class LMT observatory should cost of the order of US$500,000 ( - $0.0 + US$ 200,000). Liquid mirrors cost almost two orders of magnitude less than glass mirrors. Let us forget for a brief time that we are dealing with a LM and let us imagine that we have found a surplus 4-m mirror for a few tens of thousands of dollars. The challenge then is: What will we do with it, consider