FOVMath

How we make this

FOVMath is built from published sources and arithmetic. This page describes where each kind of information comes from, what we do when a source is missing or contradicts another, and how pages are checked.

Camera and telescope specifications

  • Only the manufacturer's own product pages, manuals and datasheets are used. Retailer listings, forums and review sites are not used as sources, even when they are more complete.
  • Each table row links to the page the values came from. The seed data was collected on October 12, 2026.
  • When a maker does not publish a value, the table says "not published". We do not fill gaps from sibling models or from memory.
  • Some values are computed from published ones and are marked: a sensor's size in millimetres from its pixel count × pixel size, a DSLR's pixel pitch from sensor width ÷ pixels across, a reducer's focal length from the native focal length × the published factor.
  • When two official pages disagree (for example a product page and a manual), the product page value is used and the disagreement is described on the relevant page.

Target data

  • Positions (J2000) come from SIMBAD, operated by CDS Strasbourg.
  • Sizes of Messier objects come from the SEDS Messier catalogue; sizes of other objects come from SIMBAD (galaxies) or from published catalogues hosted on VizieR: Sharpless (1959) for H II regions, NGC 2000.0 (Sinnott 1988) and Lynds (1965) bright nebulae. Where the default catalogue describes a different extent than the object people frame (for example the star cluster rather than the Eagle Nebula around it), the target page says which catalogue value is used for framing and lists the others.
  • "Best months" are computed from right ascension (the date an object is opposite the Sun and highest at midnight). Where NASA's Hubble Messier or Caldwell pages state a best viewing time, it is quoted with its source.

Formulas and calculators

  • Every calculator page shows its formulas and cites where they come from: an original publication, an optics text, a standards document or a manufacturer's technical note. Rules of thumb are labelled as rules of thumb.
  • The calculation code is separate from the page code and covered by automated tests with worked examples (for example, the field of view of a 23.5 mm sensor at 400 mm, or the size of a 16-bit FITS file).
  • Calculators run in your browser. Nothing you enter is sent to us.

Writing and review

  • Pages are drafted with the help of AI writing tools from the collected sources, then checked against those sources. Each page records whether the publisher has completed that check (a review flag in the page's source file).
  • We do not publish hands-on reviews, test images or claims of having used equipment. When a page discusses how something behaves in practice, it cites a source for it.
  • Pages show the date they were published and, when a correction matters, the date they were updated. Dates are never set in the past.
  • Each page ends with a Sources list giving the title, publisher and access date of every source used.

Links

Every cited address is checked automatically before publication. A few publishers block automated checks; those links are checked by hand.

Corrections

Send corrections to contact@fovmath.space with the page address and your source.