Welcome to the NavList Message Boards.


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

Compose Your Message

Add Images & Files
    Re: Lat and Long by moon transit.
    From: Jeremy C
    Date: 2011 Jan 31, 09:50 -0500
    I'll add mine to this list.  One caveat, I am limited to 25 entries on the SkyMate Pro program, so I took a sampling and got the position
    Lat N 21d 47.9'N
    Long E 130d 04.6
    I will comment that using the same numbers, people got different positions.  That tells me that all roads don't lead to the same place for sights like this.
    In a message dated 1/31/2011 3:36:03 A.M. Central Asia Standard Time, pmh099@yahoo.com writes:
    I start with the summary of the results for UT=10:00:00

    Jeremy's GPS:
    Lat: N 21d 48.7'
    Lon: E 130d 07.5'

    Kermit's result:
    Lat: 21d 47.6'
    Lon: E 130d 03.2'

    Hewitt's result:
    Lat: N 21d 47.1'
    Lon: E 130d 03.5'

    To which I add:
    Lat: N 21d 47.2'
    Lon: E 130d 05.2'

    The final step was the -95s DR shift from the moment of the last observation (for which I calculate the position, see attached) to UT=10:00:00.

    My thanks to Jeremy, Kermit, and Hewitt!

    Peter Hakel

    From: Hewitt Schlereth <hhew36@gmail.com>
    To: NavList@fer3.com
    Sent: Sat, January 29, 2011 8:33:22 AM
    Subject: [NavList] Re: Lat and Long by moon transit.

    Hi Antoine -

    To figure the latitude, I took Jeremy's highest Hs at 09-50-00 of  55° 27.5' and came up with  21° 45.0' N. Moving this to account for his ship's movement, gave me 21' 47.1' N at 1000.  (21° 48.7 N = GPS at 1000 GMT). So, I have him 1.6' south of the GPS. (You have him at 21° 47.6' N).

    Since the altitudes were taken very close to meridian passage and were changing only a few tenths/min, I was a little dubious about how my paper-and-pencil method for longitude would turn out.

    Anyway, I took the two equal altitudes - 55° 25.6' at 09-48-15 and 09-55-19 - averaged the times, and came up with an uncorrected longitude at 09-51-47 of 130° 02.1 E.  Applying the correction of .7' for ship's net motion of .4 kts directly toward the moon, gave me a longitude of 130° 01.4' E. Accounting for the ship's movement south and west between 0950 and 1000 gave a 1000 longitude of 130° 03.5' E. So, I have him 4.0' of longitude west of the GPS position of 130° 07.5' E. (You have him at 130° 03.2' E).

    You and I agree to 0.5' of latitude and 0.8' of longitude.

    For some reason your attachment came up scrambled on my Mac (was it doc.x?), so I don't know how this compares with others' results.

    Best regards.  Hewitt

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    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 Settings

    Posting Code:

    Custom Index

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

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site