1. The Celestial Navigation of Christopher Columbus;Molander;NAVIGATION, Journal of The Institute of Navigation,1998
2. A Model for the Brightness of Moonlight;Krisciunas;PASP,1991
3. Full moon occurred at 13:47 UT on February 1, 1493; the moon would have been 90 percent full or more between January 29 and February 3, but this does not mean that 90 percent is a rule, even of thumb. Individual computations of visibility, including atmospheric extinction and sky brightness, are needed for each star at every time of interest. No commercially available planetarium software (such as Distant Suns , used by Molander [1]) is this sophisticated
4. I discussed this problem with Mr. Molander publicly at the 1994 meeting of the Society for the History of Discoveries, and a few weeks later provided these same results to him (Pickering to Molander et al., November 15, 1994, possession of author), whereupon he appeared to drop the idea. So it seems strange that he apparently does not now recall the exchange or its result
5. A discussion of these, plus a probable fifth attempt, can be found on my website at http:www1.minn.net~keithpcn.htm