# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Message:αβγ
Message:abc
 Add Images & Files Posting Code: Name: Email:
Re: USCG Student Sample Problem #4
From: Greg Rudzinski
Date: 2013 Apr 26, 07:33 -0700

Antoine,

My guess on the Sun difference of 0.2' would be the way rounding of semi diameter is done between your program and USNO.

G

Re: USCG Student Sample Problem #4
From: Antoine Couëtte
Date: 2013 Apr 26, 00:51 -0700
RE : http://fer3.com/arc/m2.aspx/USCG-Student-Sample-Problem-4-Rudzinski-apr-2013-g23675

Hello Greg,

Hard to keep up with all your many publications ... , especially after the delicious BBQ and Beverages in Prisoners Harbour ! :-)

I first compared your Celestial Coordinates values with the ones I have derived : they all fit within 0.1' . Very Good !

I then computed the Intercepts and Azimuths from your various Auxiliary Positions.

The 3 Stars intercepts are within +/- 0.1' and Azimuths are the same.

For the SUN I find i = -19.8' / AZ = 126°2 , vs. your published result i = - 20.0 / AZ = 126.2°

Nothing to really worry about this 0'2 difference between these SUN intercepts. It still remains a bit surprising given the otherwise excellent match between all the other Stars intercepts.

I have (again) computed an Observed position at 06:00:00 LT through a software which automatically updates the DR Positions to each observation time. I am getting the following results :

UT 20:00:00 / N 25°09'9 / E 143°49'6 , with a LOP's dispersion of 0.1 NM (Excellent !).

This position seems to be quite close (certainly within 1 NM) from your graphic determination.

As a conclusion - and with the exception of the minor comment about the SUN intercept - I can see that our results are essentially the same.

Thank you again and

Best Friendly regards

Kermit
--
----------------------------------------------------------------
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
----------------------------------------------------------------

Browse Files

Drop Files

### Join NavList

 Name: (please, no nicknames or handles) Email:
 Do you want to receive all group messages by email? Yes No
You can also join by posting. Your first on-topic post automatically makes you a member.

### Posting Code

Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
 Email:

### Email Settings

 Posting Code:

### Custom Index

 Subject: Author: Start date: (yyyymm dd) End date: (yyyymm dd)