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    Re: Evaluation of H.O. 218
    From: Gary LaPook
    Date: 2011 Mar 24, 22:25 -0700
    I give em an "A". The second part of the tables is exactly like H.O. 249 volumes 2 and 3 so if you like using them and the accuracy is sufficient for you then H.O. 218 makes a very compact substitute. The selected star section is just as easy to use. The altitudes in both sections are limited to 10 to 80 degrees, no low angle and no very high angle shots. The Hc values include the refraction correction so you do not have to apply this correction to sextant altitudes. The correction is based on an altitude of 5,000 feet but are virtually the same as at sea level so the tables can be used as-is. All the "t" corrections stay the same for a whole year so you can just make a note of them for the current year so no need to always look up a correction in a multiplication table as when doing "delta d" for stars with H.O. 249 volumes 2 and 3. The books themselves are very compact. If your sailing is limited to a small range of latitudes say 15 or 20 degrees (which is true for most of us)  then the three or four volumes take up very little space. If you want to cover all latitudes then the entire set takes up more space than H.O. 249.

    --- On Thu, 3/24/11, Frank Reed <FrankReed@HistoricalAtlas.com> wrote:

    From: Frank Reed <FrankReed@HistoricalAtlas.com>
    Subject: [NavList] Re: Evaluation of H.O. 218
    To: NavList@fer3.com
    Date: Thursday, March 24, 2011, 8:32 AM


    I haven't had time to read all your posts on these tables, but since you've given them a thorough review, could you rate them? Are they a B+ or an A, as tables go? I haven't seen a complete set of them ever. Are they good enough for us to consider re-generating them (easy enough today) and making them available for small boat navigators and other navigation enthusiasts?


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