Stewart's Pole Star sighting at 1030


Paul Lee

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Aug 11, 2003
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Hi all,
What is the opinion of Stewart's statement that he had the pole star at 10.30pm on 14th April? This would confirm that the Californian was at 42.05 N.

By the way, before flame proof trousers are donned, I merely ask the question to start a debate.

Best to you all
Paul

 
A

Alicia Coors

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Why would that confirm Californian's latitude any more than the declination of any other star?

Polaris is a degree away from the North Celestial Pole. If a navigator were to use it to determine latitude directly, the measurement would be off most of the time (depending on its position, or right ascension, around the pole), up to 66 miles high or low. If it were used with reference to tables, it would be subject to the same sources of error as any other celestial object.
 

Dave Gittins

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I think there is a misunderstanding here. In Mersey's court. Chief Officer Stewart said at question 8798 that he took the Polaris sight at 7-30 pm. That makes sense, as at that time the horizon was visible as well as the star. On Titanic, Lightoller was getting multiple star sights at about the same time.

At 8706, Stewart said he "had the Pole Star at half-past ten." I take this to mean that he had the benefit of the Pole Star sight when working out the dead reckoning at 10-30. By then it was too late for the sight. Note also Lord's comments about the difficulty of seeing the horizon.

The sight is fairly easy, though Polaris is not particularly bright. You must have UTC, but a small error in time makes little difference. The calculations are brief. The latitude obtained should be correct within a mile or so.

For reasons of my own, I have serious reservations about the Pole Star sight story. The witnesses from Californian were a dodgy lot, with the possible exception of Gibson. For now, I'll say no more.
 

Paul Lee

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Hi David,
Yes, oyu're quite right. I forgot that you need to have a clear view of the horizon, so dusk is the best time for such stellar observations.

I'm just so confused by this. The navigational evidence, what there is of it, does seem to suggest a large Titanic-Californian distance (on the order of 20 miles), but the eyewitness evidence doesn't, apart from the low-lying rockets. I agree, with you David, that a Californian-Titanic distance of 10 miles is plausible, otherwise Boxhall's flares would be seen, but then we have people in the lifeboats, no more than a few feet from sea level, who saw "their" other ship's red light and stern, or posibbly masthead light - which brings down the distance between the two ships even more!

I don't think the word confused even comes close to describing how I feel :-(
 

Paul Lee

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Wish I'd checked the testimony more closely. Seems Stewart was on duty until 8pm - so he could have got the 7.30pm star sight - but he was tucked up in bed at 9.30. I imagine "ten" is a misprint for "seven". Quite plausible considering how bad the accoustics were in the enquiry hall!

Cheers

Paul

 

Jim Currie

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Put this one right.. never too late to learn lads!

Stewart would have quoted GMT. 10-30pm GMT was 7-20pm on board Californian.

I think if you are going to consider ship's navigation evidence, you must always bear in mind that the witness may be quoting in GMT.. the time base used for navigation.

JC.
 

Jim Currie

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PS:

I've seen it written that a pole star sight was difficult because it was not a prticularly bright star and difficult to take a sight of. Not so! Actually it was very easy! Stewart would ahve a star telescope in his sextant box. This was specifically designed to take altitude of all stars. He would simply screw it into the sextant and fire away. Done it tons of times!

JC
 

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