This is to announce a webpage that collects materials on finding telescopic limiting magnitude (TLM) with a good degree of accuracy. members.csolutions.net/fisherka/astronote/plan/tlmnelm/LimitMagFields.htm A step-by-step procedure for beginners that uses Clark's 9 magnitude charted open clusters are used in connection with Schaefer's TLM algorithm is provided. A more in-depth discussion that may appeal to intermediate amateurs is provided. Other features included referenced in the webnote are: 1) An NELM-to-MPSAS and MPSAS-to-NELM javascript calculator 2) A list of TLM and NELM areas 3) A Cartes du Ciel external database that marks A) 10 TLM measuring areas, B) 24 Landolt photometry fields on the celestial equator for use as TLM areas for small telescopes, and C) 44 NELM measuring fields of the IMO and McBeath. 4) An Excel worksheet that aids in finding your telescope's TLM based on the above. 5) Bibliography Any corrections to errors found in the site are welcomed and appreciated. This web note collects materials that grew out of a series of SAA discussions during 2003 and 2004. - Canopus56 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com