PLate OPtimizer: Difference between revisions

Revision as of 13:37, 11 November 2009

Revision as of 22:42, 19 November 2009

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'''PLate OPtimizer''', or '''PLOP''' is a [[CAD]] program developed by [[telescope]] maker David Lewis, first described in 1999,<ref>{{Citation| last = Lewis| first = David| author-link = | title = | journal = Sky & Telescope| volume = | issue = June| pages = 132-135| date = | year = 1999| url = | doi = | id = }}</ref> and used to simplify calculations needed in the design of [[Mirror#Instruments|mirror]] support cells for [[telescope]]s.<ref>{{cite web| last = Holm| first = Mark| authorlink = | coauthors = | title = Mirror Cells for Amateur Telescope Makers| work = | publisher = | date = | url = http://www.atmsite.org/contrib/Holm/Plop_optimized_cells/index.html| format = | doi = | accessdate = May 3, 2009 }}

</ref> It was based on Toshimi Taki's 1993 program PLATE<ref>http://www.asahi-net.or.jp/~zs3t-tk/cell/cell.htm Taki's brief intro to cell design</ref>, however provides a simplified user interface, thus giving it wide acceptance among makers of large [[Dobsonian]] style amateur telescopes, with good support of mirrors as thin as two inches for a diameter of thirty inches.<ref>{{cite web| last = Anderson-Lee

| first = Jeff| authorlink =| coauthors = | title = Best of 18 and Over - A collection of plop cell designs

| work = | publisher = | date = | url = http://www.cs.berkeley.edu/~jonah/18plus/| format =| doi = | accessdate = May 3, 2009}}</ref>

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==Comparisons and limitations==

A basic mirror cell may be built using minimal calculation and simple materials such as wood and outdoor carpet, with a good example being [[John Dobson (astronomer)|Dobson's]] original telescopes. However as amateurs sought to build larger and thinner mirrors they found such designs inadequate.

Many amateur telescope makers use cells which are designed via [[equal area rule]] calculation, using programs such as David Chandler's [[public ___domain]] program, ''Cell''.<ref>{{Citation| last = Chandler| first = David| title = Floatation Mirror Cell Design|url = http://www.davidchandler.com/cell.htm| accessdate = 2009-06-21 }}</ref> However such calculation does not account for mechanical stresses introduced from one part of the mirror to another. For this reason [[finite element analysis]] is becoming more commonly used to reduce such [[Yield (engineering)|stress]]. Although general finite element analysis programs such as [[Nastran]] will work for mirror cells PLOP is currently more popular in part because can can be set to ignore [[Deformation (engineering)|deformation]] which merely results in refocus of the mirror's [[parabola]].<ref>[http://www.atmsite.org/contrib/Holm/Plop_optimized_cells/cellfaq.html#old Atmsite PLOP FAQ]</ref> It is useful to calculate floating support points for mirror [[Optical axis|axial]] (rear) support however additional tools are needed to calculate potential error from mirror lateral (edge) [[Lateral support|support]].<ref>http://www.cruxis.com/scope/mirroredgecalculator.htm ''Cruxis'' site mirror edge support calculator tool</ref>