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Educational Department
- Offshore Navigation -

Lamp of Learning


Offshore Navigation Committee Advisories

The following items have been published on the ONCom web pages as topics of which both Junior Navigation and Navigation students and instructors should be aware.

Sight Folder Quality

The quality of celestial sight folders has significantly diminished over the past six months. Folders have been received which lack the required number of sights, the type of sight reduction method required, and numerous mathematical and plotting errors which indicate inadequate sight checking at the squadron level. A failed sight folder should never occur if properly checked!

Effective immediately, sight folders will be returned to SEOs ungraded, if, in the opinion of an experienced ONCom grader, the folder has been inadequately checked at the squadron level.

In addition, folders received without an accompanying form ED-33, Examination Order, will be held at Headquarters until the form is received. Squadron SEOs will be notified by email. (13 Mar 09)

Use of Electronic Spreadsheets for Exams and Sight Folders

The Offshore Navigation Committee investigated whether the use of electronic spreadsheets and other computer-generated aids should be allowed for any part of the exams in the Offshore Navigation courses.  EDN-88 was generated as a result of this study, which defines that all worksheets and plots submitted with open book exams must be prepared by hand by the student, and that computer generated worksheets and plots would not be accepted.  The Offshore Navigation Committee later discussed the use of computer-generated spreadsheets and computer-generated Sight Reduction forms, and came to a similar conclusion — computer-generated aids would not be accepted for a Sight Folder. For Sight Folders submitted for grading, each sight reduction included in the Folder must be accomplished on a USPS SR96 Form with all values entered in the applicable blocks on the form by hand; the associated plots for these sights must also be prepared by hand by the student.

GPS Time vs. UTC

Some students have observed differences between the time their GPS receiver displays and Coordinated Universal Time (UTC) that they get from sources such as the US Naval Observatory or WWV.  Check out the GPS Time page to get some insight into possible causes. (Updated 13 Feb 06)

Windows XP and Plot Tools

Some users have reported a problem running Plot Tools on Windows XP systems.  If you encounter this problem, be sure you are running the latest version (1.5) of Plot Tools dated 19 January 2000.  If you are running an earlier version, download version 1.5.  Be sure to change the file name to "winplot.exe" when you save the file on your computer, then execute (double click) "winplot.exe" to install it.  If you are already running version 1.5, then try the following work around:

  • Locate the PlotTools directory (usually installed under C:\PLOTTOOL) and right click on CLSPLOT.exe.
  • Select "Properties".
  • There should be two or three tabs, including "General" and "Compatability"; select "Compatibility"
  • Click on "256 colors"
  • Also click on "640x480"
  • Click on "Apply"

Now, run Plot Tools again.    (16 Oct 05)

Nautical Almanac CoverOn-Line Nautical Almanac Notice

The  Educational Department has the following announcement regarding Nautical Almanac data:

There are several versions of the Nautical Almanac on the Internet.  The Offshore Navigation Committee has looked at these and found that the data varies slightly from that found in the commercially printed Nautical Almanac sold by retailers and USPS Headquarters.  More importantly, most of these on-line Nautical Almanacs do not provide all the intermediate values required on the SR96 Form (such as SHA, ‘d’ and ‘v’ correction), nor do they include the ‘increments and corrections’ section.  Sight folders will be graded using the data from the printed version of the Nautical Almanac, and discrepancies will be considered errors.

Please pass this information to celestial navigation students, sight proctors, and instructors.   (16 Oct 05)

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This page last updated Friday, May 5, 2017 20:58