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On 10 Oct 2002, at 22:51, Paul Hirose wrote:

> > We spend 5 days at Hilo(19d 50.0'N  155d 01.0'W) then depart. We get a
> > departure FIX at 02:27:00Hrs after sunrise on the morning of 21/07/2002.
> >
> > 1)  What is the Zone Time(ZT) of the departure FIX?
>
> I couldn't figure out the input data behind this question. A later
> explanation, directed to someone else, cleared it up. But the scenario
> seemed so weird, I elected to disregard the problem. If it had been me
> taking departure, UT and position would have been recorded.

Probably poor grammer on my part. You need the time of sunrise at Hilo plus
the time enroute.

> 2. Total distance from Hilo Departure Point to Hanalei Bay is 296
> miles.
OK

> 3. At 9.3 knots, it will take 31.9 hours to cover the distance.
OK

> 4. The Sun lower limb is only 10 minutes from the zenith at the noon
> sight. It would be difficult to secure an accurate observation, so the
> sight should be disregarded.
RIGHT
>
>
> >     05:30:02    Moon LL
>                                       23 20.5 Hs
>                                        -2.5 IC
>  108 36.9 GHA                            -2.9 D
> -156 36.9 A lon     N21 00   A lat       65.8 R, SD, PA
>  --------                             -------
>  312      LHA       S24 49.5 dec      24 20.9 Ho
>
>   25 08.7 tab Hc    132      Z          -38.7 d
>     -24.8 d corr
>      -7.2 d corr
>  --------
>   24 36.7 Hc
>   24 20.9 Ho
>  --------
>      15.8 away
>
>
> >     05:34:11    Vega
>                                       41 39.7 Hs
>  104 05.2 GHA       N38 47.2 dec         -2.5 IC
> -157 05.2 A lon     N21 00   A lat       -2.9 D
>  --------                                -1.1 R
>  307      LHA                         -------
>                                       41 33.2 Ho
>   41 33.5 tab Hc    N056E  Z    +5.6  d
>       0.0 d corr
>       4.4 d corr
>  --------
>   41 37.9 Hc
>   41 33.2 Ho
>  --------
>       4.7 away
>
>
>
> >     05:40:00    Altair
>                                       21 57.8 Hs
>   87 04.6 GHA       N08 52.5 dec         -2.5 IC
> -157 04.6 A lon     N21 00   A lat       -2.9 D
>  --------                                -2.4 R
>  290      LHA                         -------
>                                       21 50.0 Ho
>   21 28.4 tab Hc    N088E  Z    19.8  d
>       8.8 d corr
>       8.6 d corr
>  --------
>   21 45.8 Hc
>   21 50.0 Ho
>  --------
>       4.2 toward
>
>
> >     05:43:55    Polaris
>                                       20 25.1 Hs
>  347 18.8 GHA       N89 16.1 dec         -2.5 IC
> -157 18.8 A lon     N21 00   A lat       -2.9 D
>  --------                                -2.6 R
>  190      LHA                         -------
>                                       20 17.1 Ho
>   20 00.9 tab Hc    N000E Z    59.1 d
>      13.4 d corr
>       2.5 d corr
>  --------
>   20 16.8 Hc
>   20 17.1 Ho
>  --------
>        .3 toward
>
>
> >     05:46:20    Regulus
>                                       16 08.0 Hs
>  234 16.5 GHA       N11 57.5 dec         -2.5 IC
> -157 16.5 A lon     N21 00   A lat       -2.9 D
>  --------                                -3.3 R
>   77      LHA                         -------
>                                       15 59.3 Ho
>   15 56.0 tab Hc    N 83W  Z    19.4  d
>       9.6 d corr
>       9.0 d corr
>  --------
>   16 14.6 Hc
>   15 59.3 Ho
>  --------
>      15.3 away
>
>
> 5. Time to use for the fix isn't stated, so I will make it 0530Z
> (evening of July 21 local time). My Vega LOP doesn't look too good (I
> reversed the sign of d extracted from HO 229), but the others agree at
> 21 00 N 157 00 W.
OK

> 6. From the fix position, Pailolo Channel entrance bears 100 true or
> 090 by the compass. It's only 5 miles away so there's no reason to
> attempt a highly refined answer.
>
> 7. We should be there in about 30 minutes.
OK

>
> I did all plotting on a single piece of typing paper at a scale of 2
> miles per millimeter. To do as well as I did at that scale requires a
> lot of luck! It would have been smarter to plot the celestial LOPS on
> a separate sheet at larger scale. In fact, plotting the whole trip at
> such a tiny scale didn't make much sense either. I did that to fit it
> all on one sheet. I should have just split it between two sheets. From
> now on I'll use 1 mile per mm as my smallest scale, unless a single
> long leg needs to be plotted.
>
> My "almanac" was the USNO Web site, since I don't have a current book
> almanac. I could have simulated its hourly tabulations, but the
> contortions would have been unnatural, so I just cheated and let the
> UNSO crank out each body's position at the time of observation.
Any Almanac in a storm ;^)

> Sights were reduced with HO 229. Using the message to be posted to the
> list as my sight reduction form was surprisingly inconvenient. In the
> future I'll do it on paper.

Try working up a columnar form.




Dan Hogan WA6PBY
C27 "Gacha"
dhhogan1@earthlink.net
Nav-L Page: http://www.wa6pby.com

   

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