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Author
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Topic: choosing declination correction sign
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Jim
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posted January 03, 2020 09:12 AM
If I am in the Northern Hemisphere and declination is in the Nor. Hem. then choosing the declination correction sign based off of increasing or decreasing declination is straightforward to me. If I am in the Nor. Hem. and declination is in the Southern Hem., choosing the sign is not as obvious to me. Let's say the declination is in Southern Hem and moving toward the Equator, and I am in Nor. Hem. Is declination 'decreasing' (a '-' sign for d correction) as it numerically gets smaller moving toward the equator, or is it 'increasing' (a '+' sign for d correction) as it moves closer to Equator and Nor. Hem.?
From: USA
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Capt Steve Miller
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posted January 03, 2020 09:21 AM
Declination is decreasing
From: Starpath
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David Burch
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posted January 03, 2020 09:56 AM
Another note on this...
we need to find dec at some hour and some minutes.
look up dec at the base hour and then at the next hour, that span your time of interest.
the sign of d is the way we apply the correction, so if the next dec is larger, then d is +; if the next dec is lower (numerically) then d is -.
it can get more complex than needed if we think of the equator in this picture. all that is needed is what is above.
ie we do not need to consider such sophisticated questions as is a number getting more negative, getting larger or smaller.
From: Starpath, Seattle, WA
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Jim
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posted January 03, 2020 10:27 AM
Thank you. I had a feeling I was making more of this than it was.
From: USA
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