Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site spar.UUCP Path: utzoo!watmath!clyde!burl!ulysses!ucbvax!decvax!decwrl!spar!freeman From: freeman@spar.UUCP (Jay Freeman) Newsgroups: net.astro Subject: Re: Pleiades, Meteors, Comet Halley Message-ID: <477@spar.UUCP> Date: Wed, 21-Aug-85 17:19:11 EDT Article-I.D.: spar.477 Posted: Wed Aug 21 17:19:11 1985 Date-Received: Sat, 24-Aug-85 18:54:52 EDT References: <1428@cbosgd.UUCP> Reply-To: freeman@max.UUCP (Jay Freeman) Organization: Schlumberger Palo Alto Research, CA Lines: 32 In article <1428@cbosgd.UUCP> djb@cbosgd.UUCP (David J. Bryant) writes: >I've heard stories about reliable observers back in the 1700's who reported >seeing as many as 14 stars in the Pleiades. ... I only see six, as do most >people I've talked to. ... I've never viewed the nebulosity naked eye, nor >have I heard anyone claim to. I can maybe see eight stars naked-eye under excellent conditions. I also believe I can see nebulosity filling the cluster under similar conditions, though there are a couple of necessary caveats: (1) Bright stars seem to "spread out" on the retina in any case, so that one must always suspect self-deception. My conclusions are based in part on differential observations of closely-spaced stars where there is no nebulosity (in some cases rich-field telescopic views of clusters, for there is certainly no northern-hemisphere cluster as bright and compact as the Pleiades); in part on comparing the difference in appearance of the Pleiades on the best of nights and on occasions when it isn't quite so dark. To my eyes the cluster looks distinctly nebulous on good nights. The appearance resembles what I see through 7X50 or 11X80 binoculars under similar conditions -- the whole cluster immersed in a blob of nebulosity whose diameter is perhaps twice the width of the group of six naked-eye stars. (2) A trace of fog or high cloud will make bright stars appear nebulous. Again the test is differential observations. (3) It is easy to "see" something when you know it is there. (4) I suspect that the brightest part of the Pleiades nebulosity -- the Merope Nebula -- is too close to Merope to show well for the naked eye. Thus it does not surprise me that what I see is a whole cluster full of nebulosity, not just patches near the bright stars. -- Jay Reynolds Freeman (Schlumberger Palo Alto Research)(canonical disclaimer)