CATADIOPTRIC TELESCOPE Russian patent published in 2012 - IPC G02B17/08 

FIELD: astronomy.

SUBSTANCE: telescope may be used for serial compact devices operated with charge-coupled devices for astrophotographic, spectral, photometric observations of celestial objects in the broad-spectrum, for astroclimate study as well as for serial photovisual telescopes with the effective focal aperture of 150-400 mm. The telescope contains the following components (following the ray path): main concave dish (1), the correction element comprising two negative single lenses (2 and 3) of different glass brands with the dispersion factor that is quasi-proximal in the visible spectrum, the first one being a quasi-afocal meniscus with its concavity overlooking the object, the second one with mirror surface, made of a material with lower refraction index, and a three-lens isoplanatic off-axis aberration compensator installed in front of the telescope's focal plane. The first lens following the ray path is a quasi-afocal negative meniscus (4) with its concavity overlooking the image plane, the second (5) and the third (6) compensator lenses are glued together. The first plane of the glued lens unit following the ray path is a flat one, the remaining planes have their concavities overlooking the object.

EFFECT: reduced stray light, enhanced the image quality on the periphery of the viewing field, increasing the compensator's flange focal distance.

2 dwg, 2 tbl