NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lunar longitudes, not by lunar distance.
From: Brad Morris
Date: 2009 Aug 8, 22:44 -0400
"Confidentiality and Privilege Notice
The information transmitted by this electronic mail (and any attachments) is being sent by or on behalf of Tactronics; it is intended for the exclusive use of the addressee named above and may constitute information that is privileged or confidential or otherwise legally exempt from disclosure. If you are not the addressee or an employee or agent responsible for delivering this message to same, you are not authorized to retain, read, copy or disseminate this electronic mail (or any attachments) or any part thereof. If you have received this electronic mail (and any attachments) in error, please call us immediately and send written confirmation that same has been deleted from your system. Thank you."
--~--~---------~--~----~------------~-------~--~----~
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
From: Brad Morris
Date: 2009 Aug 8, 22:44 -0400
Hi Hanno
I do not possess a transit, but that will be the instrument you will require. I believe that the instrument that you have found is for equal altitudes.
Firstly, the altitude of the objects as they cross your meridian will be at different altitudes as a function of their declination. You will likely be forced to adjust the elevation of the observation telescope to
see the moon and the other celestial object. You may get lucky and have both objects within the scope without change, but the moon's declination changes constantly.
You may obtain the expected meridian passage of the sun and moon at Greenwich directly from the Nautical Almanac to the nearest second. It is a simple matter to convert your longitude to time and predict when the
objects will cross your meridian. Alternatively, you can obtain more exact data from the Astronomical Almanac for the these objects. If you choose to use stars, then it is simple to calculate the meridian crossing.
The procedure for aligning your transit to the meridian is given in Bowditch. In my 1856 copy, there is a wonderful exposition on this procedure. Any earlier edition will have this, 1856 is not important.
-------------
Ah, sight reduction. For meridian crossings, you will only get a Line of Positon (LOP) that is equal to your latitude. May I recommend Dutton's Piloting and Navigation, 1973 or earlier. That is the textbook used
by the US Navy at Annapolis, to train cadets in celestial navigation. This is a wonderful learning tool and will explain the entire process to you, in gory detail. You can generally get a copy of Dutton on eBay for less than $20.
However, there will be no exposition of the experiment you have proposed in Dutton. If you wish guidance on transits and how to align to the meridian, you will need an older resource. Norie's, Bowditch, Moore, etc
will serve your purpose.
Best Regards
Brad
From: NavList@fer3.com [NavList@fer3.com] On Behalf Of Hanno Ix [hannoix@sbcglobal.net]
Sent: Saturday, August 08, 2009 1:15 PM
To: NavList@fer3.com
Subject: [NavList 9416] Re: Lunar longitudes, not by lunar distance.
Sent: Saturday, August 08, 2009 1:15 PM
To: NavList@fer3.com
Subject: [NavList 9416] Re: Lunar longitudes, not by lunar distance.
Gentlemen: Thanks for agreeing so graciously. Would you, too, like to proceed to more technical issues? 1. The transit. Searching for a suitable instrument I found an old invention on the net. Would you please take the effort of loading down from Google Patent the US patent 239,315. It carries the title: Altitude Instrument, and was issued to S.C.Chandler of Boston on March 29, 1881. The instrument is of simple construction, and it is not out of he question for a hobbyist to reconstruct it .The drawings show an instrument a microscope.resembling in size and shape and are clear enough to understand its mechanics and optics. BTW: Who was S. C. Chandler? J. Palisa, at that time Director of the Observatory in Vienna, Austria, reported on its practical use. Thanks to the present officers there, I have now in hand two reports by Palisa on his experiments - one in German, the other in French. I have yet to find out the exact citations. According to the reports, Palisa made experimental observations in 1888 at Vienna. The instrument he used had been built by Hartmann & Braun. According to Wikipedia, the Co existed independently from 1882 until 1999.It was located around Frankfurt, Germany. It's records are said to be kept at the Historical Institute of the City of Frankfurt Palisa says the actual implemetation included several improvements suggested by his Institute. Palisa refers to the instrument as a Chronodeik. I am still studying the reports. Perhaps you can assist in locating reports about the Chronodeik in the English language? I am eager to find out what accuracy he might have achieved. Would it be sufficient for a practical test of our concept? If you have other idea re: a suitable astonomicals transit taht van be taken along please inform us. 2. The sight reduction. I am a novice. So, if you kow how meridian transits is properly reduced please let me know, too. Palisa gave some hints. 3. DT. I reckon, Chauvette's methods are too cumbersome today when my PC can calculate accurate epherimides. I assume there are fancy programs on the market that could calculate ephemerides. However, I have MATLAB, a rather complete technical system, and would love to calculate and tabulate DT myself. Best regards, and a happy weekend! H --- On Sat, 8/8/09, George Huxtable <george@hux.me.uk> wrote:
|
"Confidentiality and Privilege Notice
The information transmitted by this electronic mail (and any attachments) is being sent by or on behalf of Tactronics; it is intended for the exclusive use of the addressee named above and may constitute information that is privileged or confidential or otherwise legally exempt from disclosure. If you are not the addressee or an employee or agent responsible for delivering this message to same, you are not authorized to retain, read, copy or disseminate this electronic mail (or any attachments) or any part thereof. If you have received this electronic mail (and any attachments) in error, please call us immediately and send written confirmation that same has been deleted from your system. Thank you."
--~--~---------~--~----~------------~-------~--~----~
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---