NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Modifications to 2102-D
From: Gary LaPook
Date: 2009 Apr 18, 16:52 -0700
From: Gary LaPook
Date: 2009 Apr 18, 16:52 -0700
I might have one of those at home, I will look when I get back from Europe. gl On Apr 19, 1:16�am,wrote: > Hi Gary > > That was quite interesting. �The 2102D can be quite a useful tool. �I perform observations on a south facing beach in the northern hemisphere and have played endlessly with the tool. � > > I just use my to determine which stars would be practical. �Since my latitude is 40 north, it places me right between the N35 and the N45 blue templates. �Therefore, the altitudes and azimuths given really don't do the trick. � > > I first plot the four navigational planets, the sun and the moon via the red template. �Then I use the blue N45 to pick out those bodies which will fall in the section of the sky that is useful to me. �Unfortunately, this is only about 135 degrees, so it kind of limits my choices. > > Once I have the list, I swap over to the Bygrave to calculate the altitude and azimuth of each. �That way, when I am ready to swing the arc, I can preset the sextant to the expected altitude and point via the compass. Generally, the star is right in the telescope! > > My motivation for the 2102E was the lack of a template for my latitude. �Gee whiz, I thought, how hard could it be to make one? �If you have looked into the excel spreadsheet in any detail, you will note it isn't exactly easy! �And if I wanted deadly accurate blue templates, it would be enormously computationally expensive. �I would extend the number of points to smooth out all of the straight line, but when I tried this approach, the display was all herky jerky. �For making a static template, though, that would be the recommended approach. > > From other postings in the archives, I get the sense that you really enjoy these non-electronic means of solution. �So do I! �Have you encountered the "Dunlap Sunrise Sunset Computer" in your travels? �A picture of it is in my copy of Dutton's. �Looks like an interesting solution to a non-trivial problem. > > Best Regards > Brad --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---