Recognising the importance of making information accessible to people with a wide range of computer systems and physical capabilities we have endeavoured to design these pages to follow the W3C HTML standards and accessibility guidelines.
All pages (except perhaps some old legacy documents) should comply with the XHTML 1.0 or HTML 4.0 DTD, either the strict or the transitional version. No JavaScript and no cookies are used. (To use the search form, JavaScript from googleapis.com must be enabled, and enabling JavaScript from this site may be helpful.)
The Accessibility Guidelines cause some difficulty for a site dealing with a frequently visual pursuit like astronomy but we have tried to make the 'alt' text for images informative. Empty 'alt' text indicates that the graphic is there purely as a part of the visual design and may be ignored by those with difficulty reading the screen. Use of images has been kept to a minimum except where these are the main reason for the page (such as a 'gallery' of photographs).
Recently authored pages have been checked for usability with
- an HTML or XHTML validator (click icon below),
- the Cascading Style Sheet validator (click icon below),
- the Lynx text-based web browser,
- the Firefox web browser using a less than full-screen (800x600 pixel) window and small (11 pt) font size.
Comments on how we can enhance these pages (without compromising the basic design principles outlined above) are welcome.
