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    Re: Moonrise video
    From: Gary LaPook
    Date: 2013 Apr 29, 00:08 -0700
    I spent a lot of time on the TIGHAR forum trying to educate Mr. van Asten about in flight celestial navigation. That forum consists of non-navigators so I had to make simple explanations.  The members of this forum are navigators and can see the problems with van Asten's theories.

    On May 25, 2011 I posted van Asten's Noonan EJN navigation articles here:


    Van Asten replied:



    I am pasting here some of my TIGHAR messages:


    This is for you guys that may have been following this discussion and scratching your heads about what is going on. This post by Mr. van Austen provides the opportunity to show that his methodology is wrong by demonstrating a basic error that anybody should be able to understand.

    Basic to all computations for celestial navigation is knowing the position of the body being observed, in this case the sun. Celestial positions are specified like locations on earth. On earth the position north and south of the equator is called latitude and the location east and west of the Greenwich Meridian is called longitude. For celestial bodies, the position north and south of the equator is called declination and the position west of the Greenwich Meridian is called Greenwich Hour Angle (GHA.) Since the earth turns, the GHA of the sun increases at the rate of fifteen degrees every hour, one degree every four minutes and one minute of GHA every four seconds. This is why accurate time is so important because if your chronometer is wrong by just four seconds you will take out a value for GHA from the Nautical Almanac that is wrong by one minute of longitude which will make the derived position in error by one nautical mile.

    In his post, Mr. van Asten states that at 17:54:53 GMT the GHA of the sun was  88-43-15 (88 degrees 43 minutes and 15 seconds. This is the same as 88° 43.2', rounded to the nearest 0.1'.) We don't have to take his word for it since it is easy for us to figure it out for ourselves by using the nautical almanac.

    Look at the 1937 Nautical Almanac for July 2nd, available here: https://sites.google.com/site/fredienoonan/resources/air-almanac-2009/sun-s-gha

    Take out the value of the Sun's GHA for 1800 GMT (the closest tabulated value to Mr. van Asten's time of 17:54:53) which is 89° 02.5'. Since this is the location of the Sun 5 minutes and 7 seconds after Mr. van Asten's time, we must make a correction for this difference. To do this we go to the Interpolation for the GHA of the Sun table available at the same site. Enter this table for the time difference of 5 minutes and 7 seconds and take out the amount the Sun moved in that time period which is 1° 16.8' of GHA. Since we are interested in finding the Sun's GHA for an earlier period, we must subtract this correction from the 1800 GMT tabulated value and find the GHA of the Sun, as tabulated in the 1937 Nautical Almanac (the almanac carried by Noonan), for 17:54:53 GMT was 87° 45.7'. Comparing this to Mr. van Asten's value of 88° 43.2'  shows his in in error by 0° 57.5' equivalent to a 57.5 nautical mile error.

    Check the math yourself:

    GHA sun {at}  1800 GMT =     89° 02.5'

    Adjustment for 5:07      = -  1° 16.8'

    GHA at 175453 GMT =        87° 45.7'


    van Asten's  GHA =              88° 43.2'

    Minus the correct GHA sun  - 87° 45.7'

    Deference              =            0° 57.5'   

    This would also produce an error in the time of sunrise of 3 minutes and 50 seconds which we can also see by using the interpolation table to find the time interval that would produce the difference in GHA of 0° 57.5' .

    Is that simple enough?


    and you can follow that thread.


    Van Asten responded:

    G.Lpk  No , this is not simple enough , on July 2 , 1937 , between 1700-1800 GMT two phenomena had equal values : the equation of time and the sun´s rising velocity per minute of time ,both amounting to 3m50s , or 00-57´-30" difference of LHA . If figures are not used in the correct sequence (first 3m50s rising sun , from 53´/13´.8 , then 3m50s equation) , the result is the 57´30" difference you notify . Start again with diagram 3 , p.27 of EJN-2008.

    My response:

    You wrote:
    "175453 GMT sunrise time the GHA of sun was  [(175453) x 15] - 180 deg = 88-43-15. " (88° 43.2')

    The GHA from the Nautical Almanac for the same time is 87° 45.7. These are two different numbers, they can't both be right. You claim you are right so you are claiming that the Nautical Almanac is wrong.


    Van Asten claimed you could calculate the time of sunrise ACCURATE ENOUGH FOR NAVIGATION by using the planning sunrise table in the NA.

    G.Lapk. Sine the Almanac sunrise time is in L.Mean.T. , the correct U.L. sunrise time at any meridian around the world can be found by applying the latitude in time units to the Almanac (interpolated) figures. The reason is that Mean Time is registered by an artifical sun , orbiting the celestial horizon with unifform acceleration at exactly 15 deg / hr. If checked by the spherics formula for sunrise U.L. at any meridian , a same sunrise time like by the Almanac listing is consistently found in hours, minutes and seconds. Seconds digits are not listed in the Almanac , outcomes are finished to minutes.

    You are attempting to use the sunrise table for a purpose it was not designed for.
    You must know the general rule that you can not go beyond the precision of your data but you
    somehow attempt to massage the data in the sunrise table to get a greater level of precision than
    the level of precision existing
    in the original data. The sunrise table in the Nautical Almanac is only approximate and is only to
    a precision of plus and minus 30 seconds (only to the nearest whole minute (and only at the
    Greenwich meridian) and then for a three day period) and  is used for planning purposes only and
    not for actual celestial navigation calculations. It is the main data tabulated in the almanac for
    declination and Greenwich Hour Angle  that are actually used for celestial navigation
    computations. The most important use of the sunrise  table is so the marine navigator can
    set his alarm clock so that he gets out of bed early enough to take a morning round or stars on
    ship board during the short twilight period when the stars are still visible and the horizon has also
    become visible. It has no such importance for a flight navigator since he can take star sights all
    long with his bubble sextant so the twilight period is not important to him. Another use of it for a
    marine navigator is by looking at the sunrise or sunset table (and the twilight tables) and then at
    the derived time entry for Aries he knows the approximate LHA Aries at twilight so can easily
    use H.O. 249 volume 1 for selected stars to preplan his shooting schedule.

     A really simple way to show that the sunrise table can’t be used in the manner that you attempt
    to use it is to look at the subsequent three day period starting, with July 5th, where it gives the
    time of sunrise as 0601, exactly one minute later than the 0600 time given for the period of July 1
    though 4 that you used. Ask yourself this question, how did the time of sunrise change by exactly
    one whole minute between July 4th and 5th? Did the earth stop rotating for exactly one minute and
    then start rotating again?

    Basic to your premise is your computation of the time of sunrise at the location that you think the
    plane was, at the time of sunrise.  You step  through this computation like this on page 28 of the
    2008 article:

    “Offset Fix had to be established. In
    Noonan's case with the aireraft's 150 mph cruise
    speed, this Fix had to be precomputed forthe coordinates
    pair (178?47'-W;OOOO9'-N) at 150 mis off
    The belonging sunrise time was charted in the
    (American) Nautical Almanac (an Air Almanac was
    not issued for the year).
    Lat 00 deg LMT 0600
    July 2,3,4 U.L.H.
    Lat 10 deg N LMT 0543
    For 00009'-N we find LMT 0600 - 9/600 x 17m =
    0559:45 LMT. By adding the West longitude in time
    units (I Ih55m08s) it is found that Upper Limb Sunrise
    for the Offset Course Shift was at 1754:53 GMT.”

    ( A navigator would never do the time computations that you did especially he would never use
    GAT since the Nautical Almanac in 1937 used GMT for all the tabulations which were for GHA,
    not right ascension, and Noonan said himself that:

     “I consider the development the Greenwich hour- angle idea the greatest contribution to the
    of navigation since Sumner, and have used it exclusively since first published in the Air
    Almanac.”  See:


    What you are doing here is assuming that the plane was located at 178? 47' west and 0? 09' north
    and then calculating the time that the sun would have risen at that location. We only have to look
    the first part of that computation since the problem there carries through all the rest of your
    computations. You looked at the “Sunrise- Sunset” table for July 2, 1937 (you actually must have
    looked at a modern Nautical Almanac because there was no such table in the 1937 so Noonan
    couldn’t have done the computation that you did, nor would he have wanted to.)  The tabulated
    values are
    only correct for the middle day of a three day period, which was July 3rd (in the modern almanac
    you used. The 1937 almanac was not arranged in three day periods) and you found that sunrise on
    the equator was at 0600 and that sunrise at 10? north was at 0543. You then did a straight line
    interpolation between these two values to determine the time of sunrise nine NM north of the
    at 09' north as 0559:45.

    “What is wrong with this picture?”

    The most obvious problem is that the data in the table you used is only tabulated to the nearest
    minute so no
    matter what you do after that with this data it can never be more accurate than the level of the
    original data. Based on your tabulated values, the sunrise on the equator (on July 3rd not the 2nd)
    somewhere between 0559:30 and 0600:30 and the
    sunrise at 10? north was somewhere between 0542:30 and 0543:30 with no way to know exactly
    where within these ranges. The uncertainty range of plus and
    minus 30 seconds in the original tabulated data must be applied to your calculated time so, using
    method, the time of sunrise at 00? 09' north could have been anywhere between 0559:15 and
    0600:15  yet you nail it exactly to
    second at 0559:45. The “Sunrise- Sunset” table in the Nautical Almanac carries a warning that
    interpolating for times of sunrise that: “rounding errors may accumulate to about 2 minutes.”
    You ignored this warning.

    Why is this important?

    You may think that I am picking nits, but this 60 seconds of uncertainty in the time causes a 15
    NM uncertainty in the derived longitude because the sun is traveling west along the equator at
    knots, 15 NM per minute. All of your subsequent calculations flow from this calculated time of
    At the end of your computations you come up with an error in Noonan’s longitude of just 9 NM
    so your
    result is swamped by the actual uncertainty in your original calculation of the time of sunrise so
    your calculation has
    no significance. You also forgot that Itasca was making smoke that blew downwind much further
    than the 9 mile error that you claim Noonan made.

    Gary LaPook


    G.Lpk. There is no reason to be impressed by anything mathematic since the GHA/LHA listing is arithmetical ; may it be that time sight , or longitude by chronometer do not have , or no longer possess a paragraph in American Practical Navigator , that does not mean that the technique not existed resp. was dispersed among navigators circles , might it be as an emergency measure.


    Well, I would think it pretty amazing that if your sunset method was well known among navigators that no one ever thought to include your sunset method in any of the editions of the American Practical Navigator since 1802 through 2002, two hundred years of publication since it designed to be comprehensive and is the definitive reference navigation text in the U.S.


    In fact you can download the entire artice at http://davidkbowman.com/wagner_noonan.pdf.
    It was written by H.A.C.van Asten. It would be interesting to have Gary LaPook's opinion on this paper.

    Don't waste your time trying to work your way through the gibberish in Mr. van Asten's two published papers.

    We have thoroughly discussed Mr. van Asten's theories on the  "Navigating the LOP with the offset method" topic, see:


    starting with reply 120

    and subsequent posts, especially reply 203 pointing out his 300 NM error in his computation of this "10 mile" error line and his admission of this error in reply 204.


    We have also dicussed Mr van Asten's theories on the "Noonan navigation error" thread starting at reply 47 and continuing through reply 80.


    The short answer, I can't believe he got his articles published because they are so full of errors. He wrote that he had a surface navigator review his papers prior to publication and I told him his problem was that he didn't have the papers reviewed by  a flight navigator, the procedures are quite different.

    Here are links to better articles.




    OK, I'll stop but you guys are welcome to read van Asten's EJN articles and to follow those links on TIGHAR and come to your own conclusions since you do know celestial.


    --- On Sun, 4/28/13, h.a.c. van Asten <hac.vanasten---.com> wrote:

    From: h.a.c. van Asten <hac.vanasten---.com>
    Subject: [NavList] Re: Moonrise video
    To: garylapook---.net
    Date: Sunday, April 28, 2013, 6:22 AM

    Appreciated Opponent ,

    I refer to your link to the TIGHAR forum , where you pin a sunrise local hour angle miscalculation on me , with the remark that I should not necessarily demonstrate how to compute such angle , since navigators (your words : "who do understand celestial navigation")know how to do that themselves with their almanacs . For 150 SM off Howland westwards your algorithm for the hour angle of the sun at sunrise U.L. ends up at 87-45.7 , U.L. in the local horizon ,sea level , time 1754:53 GMT , which is all good . Excellent . However , I do NOT fly with you to Howland , especially if for an assessment of our position you refer to the rising sun , like mr.Noonan possibly did when nearing the island in 1937 .
    If you observe sun´s upper limb in the horizon by no matter what medium , the marine sextant , binoculars , or the unarmed eye , you do not look at the mean sun . You look at the true , apparent sun which on July 2nd is 3m50s slow on the mean sun for the 1700-1800 GMT time window . Your comparison Lapook-to- Asten local hour angle , 87-45.7 versus 88-43.2 accounts for 0-57´.5 . Multiply by 15 deg/hr and find 3m50s time point difference , exactly covering the equation of time since the sun´s rising time was 3m50s identically for 13.8 arcmin velocity per minute of time (*) . From any western point on the 500 SM radius about Howland-chart circle our distance made good is (1754:53 - 1540:00) x 150 MPH = 337 SM . However , the distance to our precomputed sun-up coordinates is 348 SM : we are 11 miles short and not 150 , but 161(**) miles off destination . Proceeding for the offset lane and turn-off point by DR (***) will bring us on a 157-337 position line 3m50s x 150 MPH = 9.6 miles westwards of Howland-chart , 14.6 miles westwards of Howland-true .
    We wil not run the destination in sight , head-on on our APL , since when passing ---6 miles , 23.5 km on the port bow .
    . Therefore , not to offend you , I stay home and let you travel alone , for which the reason is that you did not follow the advise : If you observe sunset by the bubble sextant (true , apparent sun´s centre in the horizon) , KEEP TO THE BUBBLE SEXTANT for next morning sunrise but if not , you artificially shorten your night time window and as a result you undershoot destination . Mr. Noonan should have waited for (1754:53 + 3m50s) GMT = 1758:43 GMT to plot his DR offset for Howland . The mechanism is dealt with in EJN-July 2008 , p.27 , figures 3 & 4 .

    Eventually , you disqualify my on the subject articles series by stating that they are littered with errors , thereby bringing into discussion the theory´s consistency . It is true that for the relevance there is up to now no proof , but no complaint about consistency , the articles having been meanwhile gone through by many readers the world over , has been brought to my attention ,

    sincerely yours ,

    H.A.C.van Asten

    (*) Vr/min = 15´sin 67 . cos 00-09
    (**) R.Con.Nesbit in Aeroplane Monthly , Feb. 1989 , p.71 ,without further calculation , gives "approximately 160 miles off" , at sunrise .
    (***) P.Mantz remembering F.Noonan´s "Find the Island" fashion (Mantz biography ´Hollywood Pilot´ , interview) .

    It may for members of this forum be of interest to solve for the sunrise time-distance-coordinates group from sunset the evening before . It can be made for any pair of locations , here executed for the Earhart New Guinea to Howland flight , July 2 , 1937 , departure 0000 GMT from Lae . Sunset 159-07-E / 04-33.5-S . Sunrise next morning 150 SM off Howland-chart . For one single day you can delete the Equation of Time difference and work with apparent time .

    159-07-E to 178-47- W Diff.Long. due east 22-06
    LHA ---L. 90-04
    Subtract from 360-00

    Travel of true sun during (partial) trip 157-47

    Divide by 15 deg / hr flight time 10h39m08s

    Add to GAT of sunset 07 15 45
    GMT of sunrise U.L. unarmed eye 17 54 53

    Note that ---L. (any instrument , not bubble) is in the horizon . For the specific event the Equation of Time covered the rise time of the sun , both figured 3m50s . Note that sun´s centre (bubble sextant)is in the horizon --- GAT of sunrise was 1751:03 .

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