A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Antoine Couëtte
Date: 2011 Feb 10, 13:01 -0800
RE : http://www.fer3.com/arc/m2.aspx?i=115612
[NavList] These days are good for taking lunars with Jupiter.
Date: 9 Feb 2011 07:57
These days are good for taking lunars with Jupiter.
You can hold the sextant nearly vertical.
Hello to all, and in particular to Andr�s
Your last post, Andr�s, gave me the idea to carry my sextant with me since I flew from Nantes to a nearby island yesterday afternoon in order to fly tourists back to mainland early this morning.
Unfortunately I forgot my Chronometer...
So I decided to use my old trusty (and salty) OMEGA Speedmaster wristwatch in its "elapsed time" mode. I launched it shortly before my first my observation and I let it run all the way to the end. My first observation took place at Watch Time t11 = 0h00m28.0s and the last one at Watch Time t45 = 02h09m24.0s. Since I started my observations in Mid/late afternoon, I added 15h45m00,0s to all my recorded watch times, a purposely significant (and fixed) error relatively to UT. Therefore my very first sight is hereunder recorded at :
- t11 = 15h45m28.0S , while the very last one is hereunder recorded at :
- t46 = 17h54m24.0s
It thus replicates our Illustrious Forebears Lunars environment as follows : although their Watches indications did differ from UT (by an amount which is what they needed to determine), on the other hand all intervals elapsed between their observations were to be recorded with the utmost care.
I first took a series of 5 Sun shots, then 5 Moon shots, then after sunset I took 5 Jupiter shots, to finish up with 5 Moon-Jupiter Distances (near limb), which - as you earlier indicated - actually were rather comfortable since this time I did not need to lie on my back.
Date : Feb 09 th, 2011
observations took place in the [15:30 UT - 18:30 UT] time frame,
Non moving Observer
Height of eye : 17 ft above sea level, tide was high and (almost) steady.
Temperature : 12�C / 53.6�F
Pressure : 1017 Mb/hPa / 30.03 In. Hg
All heights corrected for only Instrument error (Refraction, SD and Parallax need to be performed)
The horizon was exceptionally clear and sharp/well defined.
1 - First set of Observations : 5 Sun Lower Limb shots :
Watch Time t11=00h00m28.0s T11 = 15h45m28.0s H11 = 11�39.8'
Watch Time t12=00h01m43.0s T12 = 15h46m43.0s H12 = 11�29'4
Watch Time t13=00h02m57.0s T13 = 15h47m57.0s H13 = 11�19'2
Watch Time t14=00h04m05.0s T14 = 15h49m05.0s H14 = 11�10'0
Watch Time t15=00h05m28.0s T15 = 15h50m28.0S H15 = 10�58'6
2 - Second set of Observations : 5 Moon Lower Limb shots :
Watch Time t21=01h40m23.0s T21 = 17h25m23.0s H21 = 57�28'0
Watch Time t22=01h41m15.0s T22 = 17h26m15.0s H22 = 57�24'7
Watch Time t23=01h42m48.0s T23 = 17h27m48.0s H23 = 57�18'6
Watch Time t24=01h43m37.0s T24 = 17h28m37.0s H24 = 57�15'1
Watch Time t25=01h44m55.0s T25 = 17h29m55.0s H25 = 57�09'6
3 - Third set of Observations : 5 Jupiter shots
Watch Time t31=01h47m25.0s T31 = 17h32m25.0s H31 = 31�57'1
Watch Time t32=01h48m17.0s T32 = 17h33m17.0s H32 = 31�50'2
Watch Time t33=01h49m15.0s T33 = 17h34m15.0s H33 = 31�42'3
Watch Time t34=01h50m03.0s T34 = 17h35m03.0s H34 = 31�36'2
Watch Time t35=01h51m22.0s T35 = 17h36m22.0s H35 = 31�26'0
4 - Fourth set of Observations : 5 Jupiter Lunar Distances near limb
Watch Time t41=02h05m07.0s T41 = 17h50m07.0s H41 = 29�37'5
Watch Time t42=02h06m14.0s T42 = 17h51m14.0s H42 = 29�38'0
Watch Time t43=02h07m25.0s T43 = 17h52m25.0s H43 = 29�38'4
Watch Time t44=02h08m17.0s T44 = 17h53m17.0s H44 = 29�38'8
Watch Time t45=02h09m24.0s T45 = 17h54m24.0s H45 = 29�39'1
I just - and once again – processed this Lunar from the data typed here-above, which I am going to "copy-paste" onto NavList. Therefore I would trust that there should be NO typos…
As a final result, and compared to my Google Earth position, I find a "Lunar derived position" which is "off" by 0.4' in Latitude and 4.4' in Longitude.
I first leave to interested readers to find and publish here their own solution of this Lunar, and I am planning to publish my results in a few days.
Thank you for your Kind Attention, and
Best Regards from
Antoine M. "Kermit" Cou�tte
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