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Astronav. quiz...
From: Jacquelin Hardy
Date: 1996 Oct 7, 11:54 -0400
From: Jacquelin Hardy
Date: 1996 Oct 7, 11:54 -0400
Astronav. question: My position is: Lat: 00 D Long: 000 D Today, the lenght of the true solar day equals the lenght of the mean solar day. At 1200h ship's time (zone time 0), the azimuth of the sun was 195 (T). What date is it today? Jacquelin Hardy jhardy@zone.ca ------------------------------------------------------------------------ This mail list is managed by the majordomo program. To from this list, send the following message to majordomo@ronin.com: navigation For help, send the following message to majordomo@ronin.com: help Do NOT send administrative requests to navigation@ronin.com. Thanks. -ben ------------------------------------------------------------------------ From mail Mon Oct 7 21:06 EDT 1996 Received: from dg-webo by wellspring.us.dg.com (5.4R3.10/dg-gens08) id AA11107; Mon, 7 Oct 1996 21:06:55 -0400 Received: from gw-ronin.mv.net by dg-webo.webo.dg.com (5.4R3.10/dg-webo-v1) id AA22689; Mon, 7 Oct 1996 21:06:53 -0400 Received: (from root@localhost) by gomoku.ronin.com (8.6.9/8.6.9) id UAA14725 for navigation-outgoing; Mon, 7 Oct 1996 20:45:40 -0400 Received: from ren.netconnect.com.au (ren.netconnect.com.au [203.7.198.1]) by gomoku.ronin.com (8.6.9/8.6.9) with ESMTP id UAA14719 for; Mon, 7 Oct 1996 20:45:33 -0400 Received: (from mobi@localhost) by ren.netconnect.com.au (8.7.6/8.7.6) id KAA17017; Tue, 8 Oct 1996 10:56:04 +1000 Message-Id: <199610080056.KAA17017@ren.netconnect.com.au> From: "John Simmonds" To: "navigation@ronin.com " Date: Tue, 08 Oct 96 10:45:55 +1000 Priority: Normal X-Mailer: John Simmonds's Registered PMMail 1.5 Subject: Re: Astronav. quiz... Sender: owner-navigation@gomoku.ronin.com Precedence: bulk Reply-To: "John Simmonds" Errors-To: owner-majordomo@ronin.com Content-Type: text Content-Length: 499 Status: RO On Mon, 7 Oct 1996 11:54:11 -0400, M. Jacquelin Hardy wrote: >Astronav. question: > >My position is: > Lat: 00 D > Long: 000 D > >Today, the lenght of the true solar day equals the lenght of the mean solar day. >At 1200h ship's time (zone time 0), the azimuth of the sun was 195 (T). > >What date is it today? > Easy one, 02 / 11 / 96 Cheers, John ===================================== He who has never been lost is no navigator ===================================== From mail Mon Oct 7 22:29 EDT 1996 Received: from dg-webo by wellspring.us.dg.com (5.4R3.10/dg-gens08) id AA14260; Mon, 7 Oct 1996 22:29:06 -0400 Received: from gw-ronin.mv.net by dg-webo.webo.dg.com (5.4R3.10/dg-webo-v1) id AA24582; Mon, 7 Oct 1996 22:29:00 -0400 Received: (from root@localhost) by gomoku.ronin.com (8.6.9/8.6.9) id WAA15499 for navigation-outgoing; Mon, 7 Oct 1996 22:11:18 -0400 Received: from mv.mv.com (root@mv.mv.com [192.80.84.1]) by gomoku.ronin.com (8.6.9/8.6.9) with ESMTP id WAA15494 for ; Mon, 7 Oct 1996 22:11:15 -0400 Received: from lucky.coastalnet.com (abaco.coastalnet.com [204.183.40.2]) by mv.mv.com (8.7.5/mem-940616) with SMTP id WAA23918 for ; Mon, 7 Oct 1996 22:20:48 -0400 (EDT) Received: from pm-jv1-30.coastalnet.com (pm-jv1-30.coastalnet.com [205.245.115.30]) by lucky.coastalnet.com (8.6.12/8.6.12) with SMTP id WAA29867 for ; Mon, 7 Oct 1996 22:18:37 -0400 Date: Mon, 7 Oct 1996 22:18:37 -0400 Message-Id: <199610080218.WAA29867@lucky.coastalnet.com> X-Sender: cn1907@abaco.coastalnet.com (Unverified) X-Mailer: Windows Eudora Version 1.4.4 Mime-Version: 1.0 To: navigation@ronin.com From: cn1907@coastalnet.com (w murfin) Subject: Re: Astronav. question Sender: owner-navigation@gomoku.ronin.com Precedence: bulk Reply-To: cn1907@coastalnet.com (w murfin) Errors-To: owner-majordomo@ronin.com.Ms.Hardy.writes. Content-Type: text/plain; charset="us-ascii" Content-Length: 1613 Status: RO > >My position is: > Lat: 00 D > Long: 000 D > >Today, the lenght of the true solar day equals the lenght of the mean solar day. >At 1200h ship's time (zone time 0), the azimuth of the sun was 195 (T). > >What date is it today? > The answer is November 2. The days of the year when the length of the true(or apparent) solar day equals the length of the mean solar day can be found by examining a graph of the Equation of Time (see Bowditch-84, page 491). Since the Equation of Time equals the accumulated difference between the apparent and mean solar days, when the Equation of Time reaches a minimum or maximum that difference is not changing, that is the mean and apparent solar days are of equal length. This occurs four times each year, minima on aproximately May 13 and Nov 2, maxima on Feb 12 and July 25. Next from the Nautical Almanac find the GHA of the sun at noon GMT (ship's time in the problem) for each of the four possible days. Date GHA Feb 12 356d 26.2 May 13 0d 55.3 July 25 358d 22.6 Nov 2 4d 6.5 By inspection it looks like Nov 2 is the right answer as the sun will be well to the west of the prime meridian (same as the ship's meridian in this problem). Actual calculation gives an azimuth of 195d. Where did you get these problems? Send more. Wes Murfin Email: cn1907@coastalnet.com 1409 Cando Place Voice: 910-455-8746 Jacksonville, NC 28540 From mail Tue Oct 8 03:54 EDT 1996 Received: from dg-webo by wellspring.us.dg.com (5.4R3.10/dg-gens08) id AA27240; Tue, 8 Oct 1996 03:54:19 -0400 Received: from gw-ronin.mv.net by dg-webo.webo.dg.com (5.4R3.10/dg-webo-v1) id AA10768; Tue, 8 Oct 1996 03:54:16 -0400 Received: (from root@localhost) by gomoku.ronin.com (8.6.9/8.6.9) id DAA19589 for navigation-outgoing; Tue, 8 Oct 1996 03:34:40 -0400 Received: from pe.net (root@pe.net [205.139.56.66]) by gomoku.ronin.com (8.6.9/8.6.9) with ESMTP id DAA19584 for ; Tue, 8 Oct 1996 03:34:35 -0400 Received: from mail.pe.net (gtalge@victoria [205.139.56.67]) by pe.net (8.6.12/8.6.12) with SMTP id AAA02194 for ; Tue, 8 Oct 1996 00:44:08 -0700 Date: Tue, 8 Oct 1996 00:44:08 -0700 Message-Id: <199610080744.AAA02194@pe.net> X-Sender: gtalge@pe.net X-Mailer: Windows Eudora Light Version 1.5.2 Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable To: navigation@ronin.com From: Gordon Talge Subject: Astronav. quiz... Sender: owner-navigation@gomoku.ronin.com Precedence: bulk Reply-To: Gordon Talge Errors-To: owner-majordomo@ronin.com Content-Type: text/plain; charset="iso-8859-1" Content-Length: 992 Status: RO >Astronav. question: > >My position is: > Lat: 00 D > Long: 000 D > >Today, the lenght of the true solar day equals the lenght of the mean solar day. >At 1200h ship's time (zone time 0), the azimuth of the sun was 195 (T). > >What date is it today? > >Jacquelin Hardy > >jhardy@zone.ca I get Nov. 2nd. Could be any year, but I'll go for 1996 even though it's not November yet. Resoning simular to Wes.=20 Noticed something from our English speaking cousins. Nov 2, 1996 is 2/11/96. In American it's 11/2/96. Maybe we should all use 2/Nov/96. What do you= think? Gordon +------------------------------------------------------------+ | Gordon Talge WB6YKK e-mail: gtalge@pe.net | | Department of Mathematics QTH: Loma Linda, CA |=20 | Mt. San Jacinto College Lat. N 34=B0 03' 03.6720" |=20 | San Jacinto, CA Long. W 117=B0 15' 09.5760" | +------------------------------------------------------------+ From mail Tue Oct 8 08:29 EDT 1996 Received: from dg-webo by wellspring.us.dg.com (5.4R3.10/dg-gens08) id AA07895; Tue, 8 Oct 1996 08:29:50 -0400 Received: from gw-ronin.mv.net by dg-webo.webo.dg.com (5.4R3.10/dg-webo-v1) id AA17936; Tue, 8 Oct 1996 08:29:49 -0400 Received: (from root@localhost) by gomoku.ronin.com (8.6.9/8.6.9) id IAA21619 for navigation-outgoing; Tue, 8 Oct 1996 08:14:26 -0400 Received: from mailout01.btx.dtag.de (mailout01.btx.dtag.de [194.25.2.149]) by gomoku.ronin.com (8.6.9/8.6.9) with SMTP id IAA21614 for ; Tue, 8 Oct 1996 08:14:18 -0400 Received: from mailto00.btx.dtag.de ([172.16.2.1]) by mailout01.btx.dtag.de with smtp (S3.1.29.1) id ; Tue, 8 Oct 96 14:06 MET DST Received: from funnel09.btx.dtag.de (0234263524-0001(btxid)@[194.25.2.10]) by mailto00.btx.dtag.de with smtp (S3.1.29.1) id ; Tue, 8 Oct 96 14:06 MET DST To: jhardy@zone.ca (M. Jacquelin Hardy) Cc: navigation@gomoku.ronin.com Subject: Re: Astronav. quiz... Date: Tue, 08 Oct 1996 11:05:21 GMT Message-Id: <325a3524.2270160@mailto.btx.dtag.de> References: In-Reply-To: X-Mailer: Forte Agent .99f/16.299 Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Sender: 0234263524-0001@t-online.de (Hans Thomas Feuerhelm) From: HT.Feuerhelm@t-online.de (Dr. H.T. Feuerhelm) Sender: owner-navigation@gomoku.ronin.com Precedence: bulk Reply-To: HT.Feuerhelm@t-online.de (Dr. H.T. Feuerhelm) Errors-To: owner-majordomo@ronin.com Content-Type: text/plain; charset=us-ascii Content-Length: 1148 Status: RO On Mon, 7 Oct 1996 11:54:11 -0400, you wrote: >Astronav. question: >My position is: > Lat: 00 D > Long: 000 D > >Today, the lenght of the true solar day equals the lenght of the mean = solar day. >At 1200h ship's time (zone time 0), the azimuth of the sun was 195 (T). >What date is it today? > >Jacquelin Hardy >jhardy@zone.ca > Great problem ! We think it is 2.11.1996, same reasoning as in the other answers we received while puzzling. Checking with sight reduction formulea gave LAH sun (12:00:00 UTC) =3D 004d 06.5' DEC sun =3D 14d 55.3' S Azimuth =3D 195.05 d hc =3D 74d 32,1' Is there more stuff like this out there ?? Best regards from Tom & Monika >------------------------------------------------------------------------ >This mail list is managed by the majordomo program. >To from this list, send the following message >to majordomo@ronin.com: navigation >For help, send the following message to majordomo@ronin.com: help >Do NOT send administrative requests to navigation@ronin.com. Thanks. = -ben >------------------------------------------------------------------------ >