A comet finder is a telescope that is especially suitable for detecting comets (and other non-point objects such as nebulae). This telescope must be light-strong, slightly enlarged and have a wide field of vision. In the past, these instruments used for the purpose were very simple. For example, the famous comet explorer Charles Messier served a telescope of only 60 cm long with a 6.5 cm wide opening, which roughly increased five times but only a 4 ° field of vision. Later instruments were larger. For example, Georg Merz constructed comet seekers with an opening of up to 16 cm. Mounting Comet finder
They were usually altazimutally but also parallactically mounted. Given that such instruments were rarely fixed but were mostly used mobile, they also needed to be portable and fast-configurable. It was also necessary to note that the observer did not have to move his head when searching a large part of the sky. With altazimutal mounting, the eyepiece of the telescope is made as short as possible. If not, you also use a broken telescope as with small universal instruments. For parallactic mounting, Yvon Villarceau has given an arrangement where the observer's eye always stays in the same place and Schneider in Währing for the Vienna Observatory who mounted a 16 cm diameter comet finder and a 135 cm focal length (see sketch ). Quad-circle chassis parts connect the declination axis F-F with the polarization axis as well as with the telescope s in such a way that the eyepiece of the last remains at the intersection of the extension of both axes (q-q are counterweights).
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