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From: Bill (no email)
Date: Sat Apr 02 2005 - 15:58:05 EST
> Bill, you wrote:
> "Trying my hand at Lunars. In the results on the Frank/Centennia Software's
> calculation screen, there is an angle given above "Corrected for
> oblateness." I am unable to correlate that angle to anything I am aware of
> at this point in my journey."
Frank responded:
> How did it go?
Good and bad. First try was Sun and Moon, March 16, 18:54:15 UT. Lat N 40d
27.7', Lon W 86d 55.7'. Removed the scope as per Alex's off-list suggestion,
and got the hang of finding the angle to measure the great circle distance
instead of what "looked" like the correct angle to hold the sextant. Got
them close and popped the scope on. Two minutes later had an Hs that I had
little confidence in (78d, 48.0'), but came in and plugged it into your
calculator anyway. IC -1.3', temp 50F, pressure 30.07. Results, 0.5' error,
15.7' longitude error.
Encouraged, I went back out and tried to obtain an Hs using the tips on your
lunars page. Hold sextant in both hands, tweak, rest, tweak, rest,
tweak.... By now (20:14:06 UT) the moon was higher and did not have much
contrast against the sky and wispy clouds, but managed to get an Hs I had a
high level of confidence in. Plugged the Hs in and results were 2.6' error,
1 d 19.2' error longitude.
I can only surmise you use cookies to rig the calculator like a slot
machine. Intermittent reinforcement, the toughest form of behavior to
extinguish. Big payoff first try, a loss the second try--keeps me coming
back. <G>
Have had little good "seeing" whether here, so have not tried again--yet.
Been playing with star-to-star distances when weather and time permit to
improve my technique.
>
> The unmarked angle you've noticed was there for debugging purposes at one
> point. I decided to leave it in and unmarked just for fun --a little mystery
> for the users. It's nothing important, but would you like to try guessing?
> I'll give you a hint: it's an angle that you need to calculate (well actually,
> only it's cosine) as an intermediate number in direct triangle solutions for
> clearing lunars.
This is going to be like a termite doing calculations for landing the rover
on Mars, but I think on it. ;-)
Thanks
Bill
>
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