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$James R. Van Zandt: Re: Refraction at the horizon.$

Re: Dip Anomaly
From: Robert Eno
Date: 2008 Mar 13, 21:21 -0400

I used a marine sextant bubble attachment on Chesapeake Bay for a similar purpose. In my case, I was trying to calibrate the bubble attachment using the known dip correction for my height above sea level. I still have the raw data in my logbook.

I do, however, agree with Peter that bubble sextants and bubble attachments are generally not precise enough to confidently determine dip anomalies, however, I believe it can, on occasion and with careful observation, be done.

cheers

Robert

----- Original Message -----

From: Peter Fogg

To: NavList@fer3.com

Sent: Thursday, March 13, 2008 6:50 PM

Subject: [NavList 4666] Re: Dip Anomaly

Greg Rudzinski asks:
"Can a bubble sextant be used to measure dip
anomalies from a known height of eye?"

The proposition implies using both a conventional and bubble sextant consecutively and comparing the results.

I guess one problem is that bubble sextants do not tend to give particularly precise results. They are also notoriously difficult to use (to hold level) on-board.
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$James R. Van Zandt: Re: Refraction at the horizon.$

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