Copying lens for microfilm photography.
A new lens design for precise copying exemplifies the success of the rms error function as a suitable criterion for the design of high resolution lenses. The design, a 145-mm f/4.0, gives 400-line/mm, high contrast,white-light visual resolution throughout a 30-mm flat image when used at 20:1 conjugates. On high resolution plates, a resolution of 320 lines/mm is obtained. The five-glass design has no vignetting of the marginal beams, presents no manufacturing problems, and gave full resolution when first assembled. The prescriptionwas found by the LASL 1972 Lens Design Program.
An Improved Type of Schmidt Camera
As has been mentioned in Nature1, D. D. Maksutov has shown that the aspheric plate of an f/2.5 or f/3 Schmidt camera of aperture2 not exceeding two or three feet can be replaced by a simple meniscus lens, the spherical surfaces of which are nearly concentric with the mirror surface. Maksutov pointed out that a system with a strictly concentric meniscus is feasible provided that a certain amount of primary chromatism can be tolerated, and that such a system has the valuable property of giving uniform definition throughout its curved field.
Historias de mi barrio: contemporary art in a community at high risk of social exclusion
Abstract Historias de mi barrio is a piece of pedagogic research aimed at highlighting the way art can articulate the relationship between the educational context and a neighbourhood at high risk of social exclusion. The starting point for this study was to ask whether this type of research, centred around the arts, was suitable in complex contexts and whether it might eventually lead to pedagogic improvement. The results gathered, and indeed the work carried out by the artists and university lecturers involved, together with pupils 6–12 years old and their instructors in a state school, provide evidence of a positive answer – and notably of the necessity of knowing about the socio-economic reality of the student cohort when planning learning projects and of the importance of the arts as a crucial element in education.