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Hi folks and particularly to George who is anything but " particularly slow
and/or stupid!!" I will answer his questions the best I can. A "pinwheel
fix" refers to the ideal situation of the LOPS intersecting at one point
taking the name from the toy i.e. a plastic star -shaped wheel pinned to
rotate at end of stick by wind power. My "fix":34 24.8N, 119 01.5W vs
www.Geocode.com:34 28' 25.36"N,118 40' 05.23"w. Bodies were Sun,Moon,Vega.
Data: All dates and times G reenwhich,IC =0,Dip not applicable because of
artificial horizon, HO 249 for sight reduction. Sun LL:2Hs=97d 48.3m, July
04,2003, GMT 17-00-09, assumed L=34dN,aLong=118d 56.7W. Moon LL no.1:
2Hs=59d 48.9, July 05, GMT 04-23-10, aL=34dN,aLong=118d 38.1W. Moon LL no.2:
2Hs=92 d49.8m, July 07, GMT 03-27-54 aL=34dN.aLong=119d 21.3W. Vega: 2Hs:
103d 40.1m,July 07, GMT 04-23-04,aL=34dN,aLong=119d00.0W. My resulting
fix:34d 24.8N, 119d 01.5W. Sun is Lunar Dist. body. Data: Four obs: GMT
20-53-15, 20-58-35, 21-02-40, 21-03-30, corresponding Ds: 61d 32.2m, 61
34.3, 61 36.0, 61 36.3. AP for Hc"s: 34d 24.0N, 119d 02.0W. Sun Hc=74d
36.5m,Moon Hc= 37d 30..5m. C.E.Fast 12m 25s,July 04, cleared dist"D" as per
Stark book=61d 23.0m resulting in GMT error of 00m 07s.
Reason for cocktail? Insufficient quanty of baby oil i.e. bath oil used to
make up difference in tray! Reflections at certain points of tray were
distorted.

>From: George Huxtable 
>Reply-To: Navigation Mailing List 
>To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
>Subject: Trying to understand- was "urgent help needed"
>Date: Fri, 25 Jul 2003 07:21:18 +0100
>
>Under the thread name "urgent help needed", (which seemed inappropriate, so
>I've changed it). Mike Burkes said-
>
> >Hi folks! An interesting observational situation occurred as follows:
>Using
> >Davis Artificial Horizon sites appeared ok i.e. graphing 2Hs vs. time on
>all
> >sites resulted in a near classic "pinwheel fix".However comparing "fix"
>to
> >map the results were off. Using my"fix" for Hc computations lunar
>distance
> >GMT differed by a mere few seconds indicating the flexibility of assumed
> >position choice. I feel the reason for the discrepancy stems from the
> >artificial horizon fluid being a combination of baby and bath oil
> >introducing a constant error.I did notice several aberrations while
>scanning
> >the pool. Any feedback would be greatly appreciated! Thanks! Mike Burkes
>
>
>I may be particularly slow, or stupid, but I understood very little about
>Mike's observations. What's a "pinwheel fix"? When he says comparing "fix"
>to map the results were off; how much off?
>
>He hasn't given us a single number to go on. What bodies was he observing
>sights of? From where? When? What were the resulting altitudes? What was
>the calculated position? What body was used with the Moon for lunar
>distance? What was the resulting distance?
>
>Only if we get some details to get our teeth into can we hope to respond to
>Mike's request for feedback. That's as I see it, anyway: it may be clearer
>to others, with sharper minds.
>
>I've never had much use for bath oil (or baby oil either, happy to say...).
>Do they mix? What was the intention behind this cocktail? If an oily
>substance is being chosen for an artificial horizon, it seems sensible to
>choose something really viscous or treacly, because wind won't ruffle its
>surface noticeably. Does Mike's blend of oils meet that requirement?
>
>George Huxtable.
>
>================================================================
>contact George Huxtable by email at george@huxtable.u-net.com, by phone at
>01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
>Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
>================================================================

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