@S1-A.ARPA,@MIT-MC:Lynn.es@Xerox.ARPA (05/23/85)
From: Lynn.es@Xerox.ARPA "magnitude 4.0 on April 5th. This is dissapointing. according to articles I've read here and elsewhere is should get up to magnitude 2.0, about the same as Polaris. Can anyone shed light on this?" The brightness estimates for Halley's Comet around magnitude 4 are based on trying to plot curves through a graph of magnitude estimates made during the last few passages of Halley's by many different astronomers with both naked eye and through various instruments, without any standardized methods. Then they adjust for the different distances involved in this passage of Halley's. Needless to say, the data are pretty inconsistent. Some comet experts have estimated a few magnitudes brighter after analyzing the methods used by some of the astronomers at the 1910 appearance, and after tossing out estimates made by unknown methods or suspected unreliable observers. The present measurements of brightness are dimmer than anyones estimate (apparently because we are extrapolating to a point too far before passage by the sun, for which no data have ever been gathered), so we still don't know who will be right. But remember even if the brighter estimates are right, that is equal to the light of Polaris SPREAD OUT OVER A FAIR PIECE OF SKY, which is a lot different than a pin point of second magnitude star light. /Don Lynn