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: USNA Sight Reduction?
    From: Robert Eno
    Date: 2015 Oct 19, 18:53 -0600

    Interesting post Lu.


    I presume your questions are somewhat rhetorical so the floor is open to the uniformed (as in civilian, and not Navy insiders) to offer a few possibilities.


    First off, I suspect that the US Naval Academy is bringing back celestial for less dramatic, more operational reasons. For example an accident at sea where electronics get fried and a reliable back up system is required to bring the limping vessel home or at least in close proximity to whatever assistance can be mustered to bring it the rest of the way home.  


    You do, however, make an excellent point about our enemies knocking out our GPS system but retaining theirs which would give them a significant leg up on us good guys. On the other hand, I do hope that the apocalypse planners in the Pentagon have already thought through such scenario and have plans to respond accordingly.


    As for sight reduction, is suspect HO 249 as a backup and calculators as the primary SR would be acceptable. Calculators are very reliable nowadays. I have a Texas Instruments solar-powered scientific calculator that I purchased in 1988 and it has been through the worst conditions possible and still working fine with no glitches whatsoever.  I use this in conjunction with the basic formulas and can reduce a sight in minutes.  Funny, I have a set of hard-bound HO 229 that I purchased some years ago; partly because I felt compelled to learn it and partly out of the snob-appeal of having it in my navigation library. I have used them once over the 25 years I have owned them and if I had my druthers, I would much rather pack a few volumes of HO249 than the massively-heavy 6 volume HO229 (now collecting dust on my bookshelf).


    An addendum to this: if I were a naval officer, I would also pack HO211 simply because I have a personal preference for it and it is very portable. It could be argued that the sight reduction table already contained in the Nautical Almanac would serve as an emergency back up to the calculator but I would argue that this is not the case. I have never cared for this system and for reasons already iterated in comments I have made in the past.







    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Lu Abel
    Sent: October-19-15 4:42 PM
    To: enoid@northwestel.net
    Subject: [NavList] USNA Sight Reduction?


    Okay, the US Naval Academy is resuming teaching of celestial navigation.   But has anyone heard what methodology they will teach for sight REDUCTION??


    Are they going totally non-electronic by teaching HO229 or HO249 (or maybe even NASR)?    Or will they allow the use of calculators (or a fine computer app, like list member Stan Klein's Celestial Tools)?


    I guess another way of asking my question is how far back in time are they going?   What technologies do they consider "unacceptable" in whatever scenario has caused them to once again teach celestial?? 


    Even more important, what is the scenario?    The bad guys knock out all the GPS satellites?  Okay, there are other GNSS systems, some owned by countries that logically might be the "bad guys"  I suspect they wouldn't shoot down or jam their own systems


    Or maybe jamming GPS.  I rather strongly suspect that the US has (and has had for a long time) drones that will home in on and destroy a jammer. 


    Etc, etc, etc.   Is there truly a credible scenario, or is the Naval Academy responding to traditionalists but justifying the move by citing some vague and unspecified threat to GPS and friends?



    View and reply to this message

    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