Sighting Polaris

Paul_Lee
25th May 2008, 13:55
(Obviously this is a "northern hemisphere" only question!)

When is the best time to observe Polaris? After the end of civil, nautical or astronomical twilight? I would have thought nautical twilight would be best, but Polaris is quite faint so difficult to see.....?

David Davies
25th May 2008, 16:33
Hi Paul
Observe the pole star as soon as you can see it PM and hang on to it as long as you can AM. Civil twilight (lighting up time ashore) 6 degrees below horizon to nautical twilight 12 degrees below I found the best. Wonderful star for small boat sailors in northern hemisphere, get pole star latitude and then two other stars, work them long by chrom and get position. Another interesting excercise is to get the upper and lower meridian transit of pole star, (false horizon) and get your latitude. With your latitude observe meridian transit of other bodies and get their declination. You can over time draw up your own Nautical Almanac. Right Acsension is another matter.
Regards

MikeK
25th May 2008, 19:51
Jeez you don't realize how quick the grey cells go ! Plenty of familiar words and celestial navigation was 2nd nature one time - but now ? Ah well, have another drop of the golden nectar and reminisce away to the hearts content ! [=P]

Mike

David Davies
25th May 2008, 23:39
Mike
I see you were in Macs, Pacheco and Palacio, I was mate of both 62 to 63, master of Palacio for a short while whilst looking for a shore job. When were you there?
Cheers
David

Roger Harrison
26th May 2008, 03:55
Ditto

2nd.Mate on Velarde in 1964. One of my neighbours was Chief Steward - John Gore - he'd been on the Velarde for a long time. Instead of sleeping 8-12pm I spent too much time playing cards with the occasional thirst quencher.

Mike - stop that bloody fly from my screen. Living in Perth W.A. I am used to a fly landing on my screen - have swatter ready and nearly used it on yours ! Eyesight failing !!

Roger Harrison

oceangoer
26th May 2008, 04:36
When is the best time to observe Polaris? After the end of civil, nautical or astronomical twilight?

Polaris is such a wee thing to be bothered with.
Start looking in Civil Twilight. By the time you've found it I'll have taken altitudes of 5 nice big fat stars with altitudes between 30 and 60 degs and plotted their intercepts thanks to aircraft navigation tables. :)
Seriously though, Polaris belongs in the realms of "hobby navigation" along with Lunar Distances.

MikeK
26th May 2008, 10:08
Mike
I see you were in Macs, Pacheco and Palacio, I was mate of both 62 to 63, master of Palacio for a short while whilst looking for a shore job. When were you there?
Cheers
David

Hi David, - right names - different ships ! The two I sailed on were the new ones that Andrew Weir built for chartering, offhand I can't remember dates, but somewhere late 80's/early 90's. They basically were little cellular boats with two cranes fixed to the port side so they could self load/discharge. In the relatively short time they had them they were mainly around the Indian Ocean then the Med (still on charter) The quality of steel was rubbish and the decks were rusting through in a very short time. Not the type to instill confidence in the Indian Ocean in monsoon time !

Sorry Roger, much as I would like to, the fly is indestructible ! Tried Flit and rolled up Telegraph - no chance ! Just as long as no maggots turn up.

The time I did sail with Mac's was also around the 80's in the Cortes (plus a couple others, we in UBC had to start doing time with Macs around then) which originally was the Baltic Vanguard. She (the B.V.) had her cranes taken off, chopped and lengthened 80ft and made into a gearless box feeder at Muddle Docks in South Shields. Cost UBC a few bob as they were made to keep the steel in the new bit to Ice Class 1 even though she was destined for the Med !

Best regards to you both

Mike