500 Rule and NPF Rule Star Trail Calculator
500 Rule and NPF Rule Star Trail: a planned Super Calculator tool. Covers focal length. Stub page while the tool and its worked example are prepared. Scope is.
500 Rule and NPF Rule Star Trail Calculator is a planned calculator in the technology section of Super Calculator, covering astro.
What this calculator will compute
Inputs: focal length, crop factor, aperture, pixel pitch and declination.
Formula, recorded as scope and not yet verified against a primary source: 500 rule max seconds = 500/(focal lengthcrop factor), NPF = (35aperture + 30*pixel pitch)/focal length.
Written for astrophotographers setting the longest exposure before stars streak.
Status
This page is a stub. The calculator is not built, no figure on this page has been verified against the authority that sets it, and nothing here should be used to make a decision. The page exists so that the site structure is complete and so that articles can link this concept on first mention.
The stub carries noindex, nofollow and is excluded from the sitemap.