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» Online Classroom   » Celestial Navigation   » Public Discussion of Cel Nav   » If you don't have an artificial horizon...

Author Topic: If you don't have an artificial horizon...

 - posted April 09, 2020 04:05 PM      Profile for Lance           Edit/Delete Post 

Here is my attempt at an artificial horizon.

Cost: about $20 for the leveling feet and about the same for the spirit level from the local hardware store. The bread board was a cast off and the mirror was a table decoration left over from a wedding. I failed woodwork comprehensively at school, but it came together fairly easily. Accurate? Not really, but if I spend about 10 minutes before taking sights leveling the mirror as carefully as I can, I can mostly get within 5 miles.

One issue is the bevelled edge of the mirror, which creates unwanted glare from street lights in the wrong position. I think I might put black tape over that.

Another issue these cold nights in Tasmania is fogging of the mirror, which makes stars reflected from the artificial horizon mirror get progressively fainter.

It worked better when I realized that the index error has to come off the initial height!

I wouldn't necessarily suggest it for sun sights, though, unless your horizon filters are good. A basin of water and a calm day might be better for sun sights, although I've found the Davis artificial horizon quite good. It can fog up, too - I find the plastic filters better than the glass.

From: Hobart, Australia

 - posted April 10, 2020 01:51 PM      Profile for Lance           Edit/Delete Post 
Actually, 5 miles might be a little optimistic... Much depends on the accuracy of the leveling and there are better spirit levels on the market.
From: Hobart, Australia
David Burch

 - posted April 10, 2020 02:55 PM      Profile for David Burch           Edit/Delete Post 
Right. That level is not within 5'.

There is an ongoing discussion on mirror horizons in a facebook group called Practical Celestial Navigation.


From: Starpath, Seattle, WA

 - posted April 10, 2020 07:24 PM      Profile for Lance           Edit/Delete Post 
I had a look at the facebook page. Some interesting ideas there. Thanks for the URL!
From: Hobart, Australia

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