> In the July 1986 Sky and Telescope Magazine, the Astronomical Computing > Column topic was Astronomical Refraction. It reports a simplified > calculation of refraction, > R as: > > R = 1 / tan (h + 7.31 / (h + 4.4)), > > where h is the apparent altitude in degrees and R is refraction in minutes of > arc (not minutes and minutes). Since actual refraction varies with actual > atmospheric > temperature profile (hard to know when constructing the dial), this provides > a good working average. The article also has a short BASIC computer program > to convert > true altitude to apparent altitude. The article was written by Thorsteinn > Saemundsson, Reykjavik, Iceland.
Content-Type: message/rfc822 Content-Transfer-Encoding: 7bit Content-Disposition: inline Received: from mail pickup service by csi.com with Microsoft SMTPSVC; Wed, 17 Jun 1998 05:24:10 -0400 Sender: [EMAIL PROTECTED] Received: from arl-img-7.compuserve.com (arl-img-7.compuserve.com [149.174.217.137]) by hil-img-ims-1.compuserve.com (8.8.6/8.8.6/IMS-1.3) with ESMTP id FAA10298 for <[EMAIL PROTECTED]>; Wed, 17 Jun 1998 05:24:07 -0400 (EDT) Received: (from [EMAIL PROTECTED]) by arl-img-7.compuserve.com (8.8.6/8.8.6/2.12) id FAA14182 for [EMAIL PROTECTED]; Wed, 17 Jun 1998 05:24:06 -0400 (EDT) Date: Wed, 17 Jun 1998 05:23:12 -0400 From: Daniel Roth <[EMAIL PROTECTED]> Subject: Re: refraction (fwd) Sender: [EMAIL PROTECTED] To: roger keith <[EMAIL PROTECTED]> Reply-To: Daniel Roth <[EMAIL PROTECTED]> Message-ID: <[EMAIL PROTECTED]> MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: [EMAIL PROTECTED] Received: from jupiter.ph-cip.Uni-Koeln.DE (jupiter.ph-cip.Uni-Koeln.DE [134.95.64.5]) by arl-img-4.compuserve.com (8.8.6/8.8.6/2.12) with ESMTP id FAA03388 for <[EMAIL PROTECTED]>; Wed, 17 Jun 1998 05:22:55 -0400 (EDT) Received: from localhost ([EMAIL PROTECTED]) by jupiter.ph-cip.Uni-Koeln.DE (8.8.7/8.8.7) with SMTP id LAA14436 for <[EMAIL PROTECTED]>; Wed, 17 Jun 1998 11:22:27 +0200 (MET DST) Date: Wed, 17 Jun 1998 11:22:26 +0200 (MET DST) From: Daniel Roth <[EMAIL PROTECTED]> To: roger keith <[EMAIL PROTECTED]> Subject: Re: refraction (fwd) Message-ID: <[EMAIL PROTECTED]> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Hello, please send e-mails for the sundial mailing list to sundial@rrz.uni-koeln.de and not to [EMAIL PROTECTED] Thank you for your contributions to the sundial mailing list! - Daniel Roth, sundial mailing list ---------- Forwarded message ---------- Date: Tue, 16 Jun 1998 22:31:26 -0500 From: roger keith <[EMAIL PROTECTED]> To: sundial list <[EMAIL PROTECTED]> Subject: Re: refraction In the July 1986 Sky and Telescope Magazine, the Astronomical Computing Column topic was Astronomical Refraction. It reports a simplified calculation of refraction, R as: R = 1 / tan (h + 7.31 / (h + 4.4)), where h is the apparent altitude in degrees and R is refraction in minutes of arc (not minutes and minutes). Since actual refraction varies with actual atmospheric temperature profile (hard to know when constructing the dial), this provides a good working average. The article also has a short BASIC computer program to convert true altitude to apparent altitude. The article was written by Thorsteinn Saemundsson, Reykjavik, Iceland.