Based on a discussion in sci.astro.amateur late July regarding resolving unequal binaries, I threw together some notes I have on this topic going back to 2003. http://members.csolutions.net/fisherka/astronote/astromath/ueb/Unequalbinari... Simple rules for the resolving limit for unequal binaries where the secondary is brighter than magnitude 11.5 are discussed. Resolving tables and a javascript calculator based on Peterson's 1954 model are provided for doubles where the secondary is fainter than 8.5 magnitudes and brighter than 11.5 magnitudes. Early literature is reviewed including Peterson (1954) and Treanor (1947). These are earlier studies that led to Lord's algorithm in the late 1990s. Haas (2006) resolving limit table is discussed in the context of these studies. A table of high precision binaries for telescope testing is provided after Argyle (2004). A table of double split nomenclature after Haas (2006) is provided, supplemented with proposed physical criteria. Corrections to any errors found are welcome and appreciated. In reviewing this matter further, it appears what is really needed is a javascript calculator that implements Chris Lord's algorithm. See page 11 of his paper at: Lord, Chris. Undated. A Report on the Analysis of the Telescopic Resolution of Unequal Binaries. Brayebrook Observatory. http://www.brayebrookobservatory.org/BrayObsWebSite/BOOKS/TELESCOPIC%20RESOL... I stopped short of writing this calculator due my inability to understand some of the logarithm symbols. I wanted to invite anyone here to take a shot at it. Hope these web notes are of interest and help. - Canopus56 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com