Author

Topic: interpolating LMT sunrise/LAN second estimate

Bill Brucato

posted February 11, 2004 06:26 AM
David, I've been looking over the papers you sent me regarding the problem I had with interpolating sunrise. I understand the method you've shown me but I'm stalled at the critical part of this example. Are you using a nav calculator to plot the course and speed to arrive at the new lat/long pos for the problem. It appears that I'd have to plot this out to get the new pos. This is a similar question I've had with LAN sec. est. problems I've encountered. Am I correct to assume that I need to plot the dr to find my pos. at LMT sunrise? Bill
From: Celestial Navigation Home/Online


David Burch

posted February 18, 2004 12:11 AM
No, it is not a "nav program" per se. You cannot use canned programs on the test, but you are free to compute a DR position using trig functions directly given a distance run in a given direction from a known position.
And generally, to find the new DR for the second estimate of LAN, it is best to compute the new DR, rather than plot it because it is faster and more accurate... and you are just looking for minutes of time, which can be just a small longitude interval.
You have a given speed, you have the time from present DR to first estimate (see topic on first and second estimate), and you have the initial DR and you have your course.
There is a new topic now that will soon, if not already, discuss the computation procedure.
From: Starpath, Seattle, WA


