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Author
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Topic: cassens-plath bubble horizon altitude corrections
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tkuhns
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posted August 18, 2024 10:09 AM
bubble horizon sun altitude corrections: dip,s.d.& aug. are ignored. star refraction corrections. are used. since sun h.p. is 0.0024 degrees ( 0.14') and since hp x cos.Ha is even less altitude parallax correction can be ignored. are these rules correct for sun bubble altitude corrections? thank you
From: tkuhns
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David Burch
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posted August 18, 2024 07:16 PM
Yes, that is correct. No dip because you are measuring effectively relative to the true vertical, not the visible horizon, and no semi-diameter as you are aligning the centers of direct and reflected views.
But may I ask which model of artificial horizon you refer to? They are fairly hard to find these days.
Does this manual describe your device?
I might add that even though these instruments cost about $2,000 (more than twice the cost of a good sextant they have to be used with), they are intended for use on land, not at sea. Even the very slightest motion of the boat inhibits their usage.
From: Starpath, Seattle, WA
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tkuhns
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posted August 19, 2024 09:59 AM
thank you for confirming my bubble sun alt.corrections. I was most interested in the parallax calculation. yes. that is the C-P bubble horizon. they are available from celestaire in whichita, kansas and direct from Germany for $950.00. they are best used from shoreline or an unobstructed hs altitude inland.i teach cel.nav.in the new york power squadron; my students have the most trouble with parallax calculations. moon. next. t.kuhns
From: tkuhns
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David Burch
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posted August 19, 2024 10:01 AM
Sorry i did not mention it but you are right the sun parallax is small and can be ignored for these sights.
From: Starpath, Seattle, WA
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