Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
    Re: Lunar-Distance correction for Oblateness
    From: Frank Reed
    Date: 2018 Apr 6, 11:48 -0700

    Ed Popko, you wrote:
    "This is a nice set of examples and the first time I had seen a correction factor for the Moon's Oblateness when correcting the moon's apparent to observed altitude (see page 14, step 21). For this lunar observation, the correction is not much and not likely to make any difference to the cleared distant result but since I'm noticing this for the first time, do any other NavList lunarians use this altitude correction?"

    No, you've misunderstood. There is no "Moon's Oblateness". That's not a real thing. What he has applied there is a correction for the Earth's oblateness, which slightly changes the Moon's altitude (but not in a way that you can apply directly to clearing lunars, as we have discussed). And this really ought to be obvious to you since we discussed this just recently, and Sean even posted that altitude correction which is taken directly --verbatim-- from the pages of the Nautical Almanac. This is wrong. This is not how you correct a lunar distance for oblateness. It also has nothing to do with the "methods" of DeLambre and Borda.

    Quite a few articles on lunars appeared in the late 1990s, and they are nearly all afflicted by a terrible disease: HNS --Hyper-Nerd Syndrome. It's a disease that leads navigation enthusiasts to obsess maniacally over mathematical complexity. If you can make it complex, then you will be rewarded with the admiration of other hyper-nerds, and, who knows, you might even get published in that glorious journal, The Navigator's Newsletter! If there's more arcane math, then that's better for the navigator afflicted by HNS. It creates a barrier of jargon and effort that keeps the riff-raff out. Lunars were converted in that brief era into that nightmare that the critics always claimed they were: a dominion of mathematicians, not navigators.

    Frank Reed

    Browse Files

    Drop Files

    NavList

    What is NavList?

    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)

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