Archived posting to the Leica Users Group, 2022/04/16

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Subject: [Leica] IMG: 5 minutes into nautical twilight on the 13th April at Seapoint, Co Dublin
From: imra at iol.ie (Douglas Barry)
Date: Sat, 16 Apr 2022 23:24:14 +0100
References: <badfa23b-1d40-19ec-19f1-ffd7f340ab25@iol.ie> <885BA93E-03B1-42E3-B8EE-06D6C6592BCD@frozenlight.eu>

In ordinary twilight, most of us can see fairly well without artificial 
light, but as the sun dips further, light is needed, however, it's still 
possible to discern the horizon, so that is nautical twilight. When the 
horizon disappears due to darkness, then it's impossible for a sailor to 
navigate using a sextant, hence the end of nautical twilight.

Nowadays, most modern sextants have a built in artificial horizon, but 
the one I have here which my Dad bought second hand in the 1920s and was 
used by him when he was a ship's officer, doesn't. It's probably from 
the 1890s.

Thanks to all who looked and commented at the photo, despite its flaws, 
but I'm definitely bringing a baby tripod with me the next time.

Douglas

On 16/04/2022 14:39, Nathan Wajsman wrote:
> Nice view?but what exactly does ?nautical twilight? mean? How is it 
> different from just plain twilight?
>
> Cheers,
> Nathan
>
> Nathan Wajsman
> photo at frozenlight.eu
>
> http://www.fotocycle.dk/paws
> http://www.greatpix.eu
> http://www.frozenlight.eu
>
> YNWA
>
>
>
>
>> On 14 Apr 2022, at 02:40, Douglas Barry <imra at iol.ie> wrote:
>>
>> As a warm front has swept in over Ireland, I went out in the twilight 
>> after sunset for a stroll with a camera in my pocket, and, at about 30 
>> minutes after the sun went down, nautical twilight began. I hadn't 
>> brought a mini tripod, so this 5 second exposure was done on a flat bit 
>> of railing.
>>
>> Nautical twilight beside the sea at Seapoint, Co. Dublin.
>>
>> http://gallery.leica-users.org/v/DouglasBray/5+mininutes+into+nautical+twilight+on+the+13th+April+at+Seapoint_+Co+Dublin.jpg.html
>>
>> Fuji X100S. Can be seen larger.
>>
>> Douglas
>>
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In reply to: Message from imra at iol.ie (Douglas Barry) ([Leica] IMG: 5 minutes into nautical twilight on the 13th April at Seapoint, Co Dublin)
Message from photo at frozenlight.eu (Nathan Wajsman) ([Leica] IMG: 5 minutes into nautical twilight on the 13th April at Seapoint, Co Dublin)