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 fromin one part of thea telescope mirror toby another.For this reasonpart, whereas[[finite element analysis]] iscan becoming more commonlybe used to reduce such [[Yield (engineering)|stress]]. Although general finite element analysis programs such as [[Nastran]] will work for mirror cells, PLOPan isadvantage currentlyof morePLOP popularis inthat part because canit can be set to ignore [[Deformation (engineering)|deformation]] whichthat merely results in refocus of thea mirror's [[parabola]].<ref>[http://www.atmsite.org/contrib/Holm/Plop_optimized_cells/cellfaq.html#old Atmsite PLOP FAQ]</ref> ItPLOP iscan usefulbe used to calculate floating support points for a mirror's [[Optical axis|axial]] (rear) support; however, additional tools are needed to calculate potential error from a mirror's lateral (edge) [[Lateral supportLateralsupport|support]].<ref>http://www.cruxis.com/scope/mirroredgecalculator.htm ''Cruxis'' site mirror edge support calculator tool</ref>
Mirror cell calculations, whether using PLOP or another program, do not overcome errorerrors introduced by gluing the mirror to its cell, excessive tightening of edge supports, nor impingement of the cell structure onto the mirror as result of differential cooling shrinkage. The significantly more complex calculations arising from the support needs of large [[honeycomb mirror]]s and those using [[active optics]] systems are outside the design parameters of such programs.<ref>http://medusa.as.arizona.edu/lbto/tech/ua9502.htm Mirror Support System for Large Honeycomb Mirrors</ref>
