NavList:
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Re: Leg 55 results
From: Dan Hogan
Date: 1999 Jun 21, 12:11 EDT
From: Dan Hogan
Date: 1999 Jun 21, 12:11 EDT
>Here are partial results from Leg 55: > >1. Mar 16 2101Z DR = 47 20 S 122 52 W OK Lat a tad off on Lon >2. To 52 30 S 100 00 W, TC = 109, dist = 930 nm Very Close in TC. nm oof per Lon >3. Compass course = 82, speed made good (not asked) 10.8 Very close same diff as Q2. >4. Mar 17 0520Z fix, all over the ocean. My 0520 DR is 47 42 S 121 >20 W. I reduced all 5 sights, and the LOPs are everywhere! Some of >the intercepts are more than 2 deg. Just pick 3 sights that are spread apart as close to 90 degrees as you can. >Conditions here are not the best. Since I don't have the 1999 >Almanac, I'm following the instructions for using last year's edition >(deduct 15.1' from GHA Aries). Also, I don't have an HO 229 for this >latitude, so I'm using the reduction tables in the Almanac. Between being >rusty and using unfamiliar procedures, probably have made some blunders. > >body time GHA aLon LHA dec Hc Zn >Betelgeuse 02:50:00 127 58 120 58 7 N 7 24 34 16 351 >Procyon 02:51:10 102 13 121 13 341 N 5 14 34 14 23 >Peacock 02:51:24 270 43 121 43 149 S56 44 17 52 197 >Regulus 02:52:22 65 15 121 15 304 N11 58 12 15 56 >Bellatrix 02:53:11 136 16 121 16 15 N 6 21 34 04 342 If you have WEB access got to the Navigation-L page (http://nav.cnchost.com) and down load ALMNAC20.ZIP. It is free ware and will provide sufficient accuracy for Silicon Sea. >All plotting was done on sheets of typing paper. DR computations by >E6-B air navigation slide rule. Sight reduction by paper and pencil. By >the way, keeping up with Silicon Sea with traditional methods is pretty >time-consuming, which is the main reason I don't always participate. I've >noticed everyone else seems to use computers. POSPLOT.EXE is a freeware program to print plotting sheets on 8.5x11 paper. I have used it on Laserjet and Deskjet printers. On the boat I use the Q.E.D. plotting sheet. There are several freeware and Shareware Sight Reduction programs available at the Navigation-L Web site. I use NAVIG94, shareware, for the Silicon Sea on the computer. >I may go back to HO 211 for reductions. The thing I like about 211 is >that you don't have to contrive an "assumed position" which is miles from >your DR, and different for each sight. You simply use your DR for the AP. > The computation is more involved than HO 229 or the NAO tables, but you >get some time back from the simplified plotting. Plus, as soon as you >compute the intercept you get instant feedback on the agreement between >the LOP and your DR. When I first started in navigation I used 211, but I was prone to making mistakes with it. I used H.O. 208 and reached a point where I could reduce a FIX within five minutes. The inspection tables (249 & 229) are faster. I currently use a pair of HP 32SII calculators, one for Mercator Sailing DR and one for Sight Reduction. Dan Hogan WA6PBY dhhogan@XXX.XXX Navigation-L: http://nav.cnchost.com