test

[BrianJ]

If we look up the "good" book when doing Celestial calculations, we see for example the Sun's rise quoted as
1 Nautical
2 Civil
3 Rise.
For 37* 51.6'S x 144 * 57.9' E today, there is almost an hour difference in times quoted.
Which would YOU use and why.
Correct answer gets a bottle of Penfolds "Koonunga Hill Shiraz 1999 Cab Sav. Naturally you have to collect it in Melbourne, or the next time I'm in UK I will bring it over.

BrianJ

 

[romany123]

Brian
If I win will I have to wait till the sun is over the yardarm to drink it .....that begs the question civil/nautical/yardarm?....mmmmm.more questions than answers.

Dave

 

[HaraldS]

If I win, I will make a note and come and collect the bottle by boat, but it may take some years...
Ok, I think for celestal navigation I would use Nautical Twilight as it tells approximately how long, or from when on you will have a usable horizon. Technically Nautical Twilight ends when the sun drops more than 12 degrees below horizon and the Civil TL is defined at 6 degrees.
Beyond the Arctic Circle you can have days where have either Twilight for the whole day. Your one hour between Nautical Twilight and sunrise is not so long and shows that you are in a warmer climate...

 

[Miker]

Brian, if I win I'll collect it next time I am in Oz. Might be in S...y, though.
On my course all the calculations were done using civil twilight as the observation time, ie the time that the horizon and stars are visible. Although I suppose that both can still be seen at Nautical twilight.
I've never tried any celestial navigation. I don't own a sextant, only sail in the Irish Sea, and there are never any stars out anyway.

PS Is there a runners up prize of a few cans of VB?

 

[ParaHandy]

Tsk, tsk....one's corrected for Summer Time (or NZ ST to those who live on "West" Island)! Fancy not knowing that.

 

[mikeb]

I believe that the accepted time top take sights is from halfway between nautical and civil until halfway between civial and sunrise.

During that period of time the accepted wisdom is that there is sufficient light to be able to see the horizon but not enough to make the stars invisible.

Cant speak from practical experience but that is what we are taught on the Ocean Yachtmaster course

 

[david_e]

Whether I win or not you can deliver a bottle to any one of my many rellies in and around the Melbourne area, this is for the priveledge of being able to hurl abuse at us POMS any time of the day or night!

 

[Seafort]

Generally stars can be observed when the Suns centre is more than 3* below the horizon. The horizon gets too indistinct for observation when the Sun's centre is depressed more tha 9* below the horizon. The middle of these times (6*) is the given time of Civil twilight.

Therefore, work out when Civil twilight (for your position) is and (depending on the magnitude of your chosen stars) aim to start observations at Nautical minus Civil twilight times before Civil twilight. (Well it works for me).

Yes! I do own a sextant, I also use it. The un-initiated find it amazing and some women find nav' by the stars "Romantic" (?).

DF

 

[jollyjacktar]

What is second prize?

Is second prize two bottles of that Aussie plonk?

 

[BrianJ]

Re: test results

Hi all
All good replies… cannot differentiate best reply, so everyone WINS… catch is that you must collect it here and share it over dinner at my Club.

Seafort… Yes I have one also, once took it to Fiji as I was doing a delivery to NZ and thought I would practice en route… guess what, not one day could I shoot anything. Must admit all male crew , so cannot verify if your theory is correct about females " women find nav' by the stars "Romantic" (?)."
Perhaps I should walk down the pier tomorrow and make believe I am working out a sight…. there are always tons of "birds" on the St Kilda Pier.

++++++++

David….Its not normal for Aussies to hurl abuse at our beloved "cousins " across the seas.. we Love Poms
Surely you have picked up that by all the NICE postings on this BB . Your Melbourne relies ( seems they have seen the light) would confirm that, but the prize stipulates YOU must drink it.
+++++++

Mike b… I should do my "Ocean", am only "offshore" , but have the miles up I think for the offshore. Good reply . Thanks

+++++++
Parahandy… what a dill I am , I should have known about "east" island.. You cannot have a bottle though as you would only sell it. !!!!

++++++
HaraldS… by the time you get here the wine will be at its peak.. but rest assured I wont open it till you arrive.. you will be welcome. Hadn't thought about the Arctic circle situation .. interesting. I am glad I live in a warmer climate.

++++++++
Romany 123… Dave, lets not quibble.. we will have a couple of VB's before opening the Penfolds .. Agree ?

+++++

Miker.. Your disqualified, you mentioned that Chinese Gentleman " Sid Lee " again. ( you did that on purpose) How about telling us about sailing on the Irish Sea. I know nothing about that area, have only been to UK a few times , but it was always work. Did promise myself that one-day I would sail into St Kath's. Fell in love with that place.
OK being disqualified means you qualify for the VB

++++++++

 

[david_e]

Re: test results

Thanks Brian, invitation accepted. Last time I sailed in Melbourne was out of St Kilda in 1977/8 about the time when we the ashes 5-1 and Both was devastating. Was on a working holiday staying in Eltham at the time and saw an ad for crew. Went down and met the owner, Irish chap, and puddled around the bay for a few hours. I got quite bored with this and in the end bought my own little Heron dinghy which I sailed both there and up at the huge reservoir in Northern Vic, name escapes me as I type. Had it for six months and sold it before I left, many happy times!

As for the Ozzies, well I concluded that they hate all other nations, except for the colony of Tasmania of course who are their loyal subjects, but hate the poms least)

ps just remembered - Eildon reservoir - yes/no?<P ID="edit"><FONT SIZE=-1>Edited by david_e on Sat Feb 23 08:18:38 2002 (server time).</FONT></P>

 

[LadyInBed]

Re: test see this website . . .

http://scienceworld.wolfram.com/astronomy/CivilTwilight.html

 

[BrianJ]

Re: test results

Spot on David... Eildon weir... which is now about 50%full due to a complete lack of rain in Melbourne over the pat 4 years.
I am a member at St Kilda(RMYS) ..
No you have it wrong... we love 'em all as long as they are not........ well You know.
Brian

 

[BrianJ]

Re: test see this website . . .

Nigel ... perfect. As soon as I get back from sailing today I will get into that site again Loks good. Thanks.
BTW good sailing day here today.
Brian

 

[Guest]

I work on the theory that the sun is ALWAYS over the yardarm somewhere in the world. From 10.00AM till 12.00AM it is past midday in New Zealand, before 10.00AM we usually drink to Argentina's health, let's face it they need it right now....

So it is never too early for a drink. Besides a morning nip is really just a late drink from last night not an early one for today.

 

[BrianJ]

I'll drink to that.
BrianJ