Expedition Navigation Software 
1 of 1- nico_sanfe
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Offline - From: Italy
- Registered: 5/20/2019
- Posts: 15
Polar % day/night and optimal
I saw in the polars the possibility to assign a diffent percentage during day and night: in which way day and night are defined?
Also, if I assign a certain % to the nav polar and then I do an optimal routing over a range of polar% (P%), I have in the results that only the day polar scan over the different %, while the night is fixed to what I have assigned in the nav polar: is this done on purpose ? Wouldn't be better to scan over % also for the night ?
Thanks Nico
- Nick
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- Registered: 9/16/2015
- Posts: 2,740
Re: Polar % day/night and optimal
It uses civil twilight - it seemed the most appropriate.
- nico_sanfe
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- From: Italy
- Registered: 5/20/2019
- Posts: 15
Re: Polar % day/night and optimal
Thanks,
what about the second question (routing over % polar?
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Thread Starter- Nick
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Re: Polar % day/night and optimal
I just understood the second part of the question. Will investigate on Monday
- nico_sanfe
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- From: Italy
- Registered: 5/20/2019
- Posts: 15
Re: Polar % day/night and optimal
I see that in version 11.6.0 the optimal routing polar% works correctly.
Thanks Nick.
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Thread Starter- SiljeWith
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- Registered: 11/17/2017
- Posts: 25
Re: Polar % day/night and optimal
Does expedition look up civil twilight in a table kind of, for position and time, or is this contained in the forecast input.
is this in all forecasts?
in short, my question is "what is the source for civil twilight"
best regards
silje
- Nick
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Re: Polar % day/night and optimal
It is a calculation in Expedition, based on data from the US Naval Observatory.
You can also right-click on the chart and select Astro from the pop-up menu.