1A lens or other object which causes refraction.
- ‘He contributed to the theory of refraction, and as a result of his theory of the wave form of light he was able to calculate the refraction within the lenses and make refractors with lesser chromatic and spherical aberration.’
- ‘Each GSP student builds a complete 60-mm diameter f / 12 refractor and mount.’
- ‘Your doctor may use a computerized refractor to measure your eyes and estimate the prescription you need to correct a refractive error.’
- ‘The results demonstrated that trained nurses and lay screeners achieved similar accuracy rates administering the two automated refractors.’
- ‘An arc of white light shone through the carefully planned refractors near its crest, making the Citadel look like an archer's bow drawn to the sky.’
- 1.1 A refracting telescope.
- ‘Secretary Martin Armitage said: ‘We will have our observatory telescope aimed at the Sun, as well as our pride and joy - a special solar filter attached to a premium refractor.’’
- ‘Italian mathematician and astronomer Galileo Galilei used the first optical telescope, a refractor, in 1610.’
- ‘Lowell established an observatory on Mars Hill in Arizona and the telescope he used - a superb Brashear refractor - has been sitting here, unused, for years.’
- ‘One evening he was observing with a rather crude refractor (a lens telescope), with a focal length of 24 feet.’
- ‘The Big Bear investigators used a telescope of only modest size - a 6-inch refractor.’
- ‘Actually it was the biggest refractor (lens telescope); Sir William Herschel, who had died in 1822, had previously constructed larger reflecting telescopes (using curved mirrors) out at Slough.’
- ‘At the same site you can take a virtual tour of the observatory and its telescope, whose refractor is still the largest of its kind in the world.’
- ‘The nine-centimetre Orion refractors are best-suited for viewing the moon, but there's something to be said for being able to do it from the comfort of your plunge pool.’
- ‘This he equipped with a small refractor: a lens telescope with an aperture of four inches.’
- ‘K. Sakthivel of the Astronomy Club said that the group of observers used a 60 mm refractor to project the image of the sun upon a flat surface where it could be viewed comfortably.’
We take a look at several popular, though confusing, punctuation marks.