NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Swinging the arc: two methods, one preferred
From: Hewitt Schlereth
Date: 2011 Jan 7, 00:40 -0400
From: Hewitt Schlereth
Date: 2011 Jan 7, 00:40 -0400
Thanks, Frank. I think I've got it. Weather permitting, I'll have a go tomorrow. -Hewitt On 1/7/11, Frank Reedwrote: > Hewitt, you wrote: > "In thinking about this technique further this afternoon, I now visualize it > as analogous to inverting the sextant to bring the horizon up to a star. But > then, instead of flipping the sextant back to "normal" you hold the scope on > the star and rotate the sextant around the axis of the scope. Thus instead > of swinging the star (sun, moon, planet) across the horizon, you swing the > horizon around the body." > > Yes, that's just right. Now, turn the sextant back right side up and do > whatever motion is required to get the same visual effect. You'll find that > you're turning from side to side while you're rotating the instrument. As > Paul has said, it's hard to describe but easy to do if you follow the simple > rule that the Sun or star should remain centered in the field of view. It's > not hard to learn at all, and it's not hard to teach if you have the > students right there with you. It is, however, hard to explain in words. > This whole business would benefit from an animation or a simple video. When > you've seen it done, there's nothing to it. > > -FER > ---------------------------------------------------------------- > NavList message boards and member settings: www.fer3.com/NavList > Members may optionally receive posts by email. > To cancel email delivery, send a message to NoMail[at]fer3.com > ----------------------------------------------------------------