Schmidt telescope

The original bend and polish idea is due to Bernard Schmidt who built what has become known as a Schmidt telescope with a spherical primary and an aspheric corrector plate that introduces exactly the right amount of spherical aberration to cancel the spherical aberration that would be introduced by the spherical primary (Schmidt). The corrector has to be thicker at the edge in proportion to the radial distance in the aperture to the fourth power to provide the needed correction. 

Most of the stars of our sample have been selected from the H K BPS survey ( Beers, Preston Shectman [1], First, stars were selected from the weakness of their H H lines for the Balmer lines intensity on prism-objective Schmidt telescope plates. Then, the candidate stars were observed with a slit spectrograph in order to have a quantitative estimate of their metallicity. The survey has operated on about 7000 square degrees of the sky, mostly on the polar caps. It has supply a vast amount of metal-poor stars, with hundreds of them more metal-poor than the most metal-poor globular clusters. We selected from this sample stars with metallicities estimated to have [Fe/H] < -2.7. The actual metallicity histogram is given for the sample on fig. 1. 

We can detect it in the Galaxy up to several kpc from the sun on objective prism plates of the Schmidt telescope. 

We have been making survey observations of faint cool carbon stars using the Kiso 105-cm Schmidt telescope. Kodak IN and 103aF plates are respectively taken behind the 4-degree objective prism (700 Amm-1 at Ha) for the detection and for the spectral classification. F-band plates are utilized to obtain the position and... 

The Rotation Modulation Collimator was originally conceived by Mertz [9] as a technique to encode an image formed in the focal plane of an optical Schmidt-telescope to allow electronic read-out by a photomultiplier. The technique was soon adapted to image forming in X-ray astronomy by Schnopper et al. [11], and was successfully used in a number of rocket flights to localize X-ray sources with good precision [12,14]. In 1974 the UK ARIEL-V and in 1975 the NASA SAS-3 satellite was launched both equipped with RMC systems. The source localizations provided by ARIEL-V and SAS-3 led to the discovery of many new X-ray sources and the identification of the optical counterparts of several sources [13,15,16]. 

Schmidt telescope (Bernhard Voldemar Schmidt) Schmidt s telescope uses a spherical main mirror and a correcting lens at the front of the scope. It can photograph large fields with little distortion. 

The standard 0.75 M Spectraspan III has an approximately 6 cm x 7.5 cm display. Since the CID used is only 1.1 x 0.85 cm, only a very small portion of this display could be observed at any one time. However, this problem has been recently reduced by substituting a 15 cm focal length, f/1.4 Schmidt corrected Cassegrain telescope (Nye Optical, Spring Valley, CA) for the camera mirror (Figure 3). This reduces the display dimensions five fold. The focal plane remains flat and a minimum resolution of 0.1 nM is achieved. With this optical system the entire 200 to 800 nM region cannot be viewed simultaneously. Further image reduction is possible, but resolution will be compromised... 

Catadioptic telescopes use both lenses and mirrors. The most widely used astronomical instruments in this class are the Maksutov telescope and the Schmidt... 

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