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From: hogg@utcsri.UUCP (John Hogg)
Newsgroups: sci.astro
Subject: Re: Solar filters
Message-ID: <3493@utcsri.UUCP>
Date: Thu, 16-Oct-86 09:06:24 EDT
Article-I.D.: utcsri.3493
Posted: Thu Oct 16 09:06:24 1986
Date-Received: Thu, 16-Oct-86 10:03:51 EDT
References: <779@ur-tut.UUCP>
Reply-To: hogg@utcsri.UUCP (John Hogg)
Organization: CSRI, University of Toronto
Lines: 17
Summary: 

The best filter to use for looking at the sun is (surprise) one that has
been designed for looking at the sun.  These can be obtained for about
$36 Canadian at current rates, and you get a wonderful bonus: there's a
sextant attached.  The model I'm thinking of is the Davis Mk III.  It's
cheap, it's plastic, but it works.

The disadvantage from the astronomer's point of view is that these filters
cannot be installed on a telescope.  However, they are designed to be used
for staring at the full sun for extended periods, and therefore presumably
filter out all harmful rays for direct viewing.  I've used mine in past for
eclipse watching with no noticable effects.  (The issue was moot this time
around.)
-- 

John Hogg
hogg@utcsri.uucp
hogg@csri.toronto.cdn