NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Robert Eno
Date: 2019 Jun 14, 09:46 -0600
I will wade in here, having a considerable amount of practical experience with bubble sextants and marine sextant bubble attachments. I will try to be brief.
I had a C&P bubble attachment but ended up selling it because the size of the bubble is fixed and I found I could not obtain accurate sights with it. In my opinion, and I may face some criticism for saying so, unless you can adjust the size of the bubble, the instrument is of questionable value as a means of obtaining accurate fixes. I still have a C.Plath attachment that has a provision for adjusting the size of the bubble and this instrument, I have found, is far superior to all others that I have come across.
To answer your other questions:
1) Is anyone here who can share his practical experience with this type of sextant on land or at sea ?
Yes to both. I have been able to consistently fix my position on land, within ¼ of a mile using my C.Plath bubble attachment. At sea? Forget about it. It will drive you insane trying to stabilize the bubble. I have even tried observations when in harbour and with dead calm water. The bubble still scoots around because your boat is always moving to some degree, although I was able to get some reasonable sights under calm condition in the harbour. If you were ever in a position where you needed to fix your position from a harbour and with no other means of determining your position, I would go ashore and take your sights there. In the old days, pilots, when flying in the arctic, would regularly land on lakes, go ashore (in open water season) and take observations using an artificial horizon.
2) Is it suitable to do lunars from the backyard ?
Yes, for the altitude portion of the exercise. I have done dozens of lunar observations on land using my C.Plath bubble attachment.
3) I could not found manual or technical description of this particular bubble horizon attachment on internet. Does it exist ?
I believe C&P does/did sell this unit with an instruction booklet. I suggest Celestaire is the best source of this information.
I am sure other, more knowledgeable folks on this forum will chime in with additional information.
Robert
From: NavList@fer3.com <NavList@fer3.com> On Behalf Of Igor S.
Sent: June-13-19 11:02 AM
To: enoid@northwestel.net
Subject: [NavList] C&P bubble sextant - practical issues
Hello everyone,
I was very happy to borrow C&P sextant with bubble professional horizon (see picture below). After eliminating side error and reducing index error till1' I was trying to "catch a star" together with bubble in the crosshairs but found it very difficult. Perhaps I need a solid support for hands and more experience ..
I have further several questions:
1) Is anyone here who can share his practical experience with this type of sextant on land or at sea ?
2) Is it suitable to do lunars from the backyard ?
3) I could not found manual or technical description of this particular bubble horizon attachment on internet. Does it exist ?
kind regards,
Igor
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