Poncet platform
A Poncet platform or Poncet mount is a type of equatorial platform .
function
It is named after its inventor. This type of telescope mounting makes it possible to get a smooth tracking with a Dobson telescope , just like with reflectors, or refractors , which have a motor-driven GoTo mount or another tracking system. The telescope thus follows the movement of the starry sky without having to carry out the typical Dobsonian "replenishment". This gives freedom for longer observation times and also enables astrophotography on the Dobsonian telescope, which is almost impossible without an equatorial platform, since the Dobsonian was designed for purely visual observation.
Background and usage
Invented in 1970 by Adrien Poncet . 1977 in the January issue of "Sky and Telescope" described and illustrated. Often designed as a simple plywood construction with a sturdy base that bears the weight of a Dobsonian and its substructure. The Poncet platform can be implemented without complicated and expensive special tools, with DIY skills and a normal household workshop, as well as some materials that are available in every hardware store. Platforms of all sizes have been built, from giant platforms carrying entire small observatories to miniature formats. The angle of incidence of the circular section at the lower edge of the upper plate is derived from the degree of longitude, and enables the entire superstructure to be rotated in an imaginary extended axis to the North Star. If the platform is to be used in an observatory which is located at 50 ° north latitude, the angle must be adjusted accordingly. You can therefore only use the platform depending on the location. If you were to build a platform that is used directly over the equator, you would theoretically only have to screw a board onto a roller or barrel, then attach the Dobsonian telescope to it, and attach a length-adjustable support strut. However, since very few people live on the equator, a section of a circle must be used (upper plate), which slides on rollers or plain bearings (lower plate).
The platform enables adequate tracking even at higher magnifications and in astrophotography. The tracking time is usually limited to about 1 hour, similar to a "barndoor tracker", after which you have to reset the platform, then realign the Dobsonian before you can continue "spechtling". Another version of the equatorial platform is the " Gee platform " and the platform by Georges D´Automne .
literature
- Martin Mobberley: Astronomical equipment for amateurs. Verlag Springer, 1999, ISBN 1852330198 , p. 94f ( limited preview in the Google book search).
Individual evidence
- ↑ Archived copy ( Memento of the original from February 25, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
