NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Best Budget Sextant for Novice Celestial Navigators
From: Lu Abel
Date: 2016 Nov 10, 21:31 +0000
From: Lu Abel
Date: 2016 Nov 10, 21:31 +0000
I've been teaching celestial for the US Power Squadrons for about 20 years. Here are my opinions:
Davis Mk3 - remarkably accurate for its very inexpensive price, but not a good sextant for learning. Without a true micrometer drum, it's hard to get readings to within a few minutes, much less a few tenths of a minute. Good emergency sextant, but not good for learning.
Davis Mk15 (and 20 and 25) - remarkably good as a true sextant, easily produces results to a few tenths of a minute. Biggest issue I've found with them is that is some backlash in the drum, meaning that you get different readings (by tenths of a minute) bringing a body down to the horizon vs bringing it up. I tell my students to be sure to measure Index Error in the same direction (up or down) as they brought the body.
Astra - truly great. Easy to handle and very accurate.
I have no experience with Russian sextants such as the SNO-T.
I have handled WW II sextants which seemed great but were very heavy.
For anyone buying a used sextant, I would urge that you be allowed to have it checked by a true sextant shop (eg, Robert White Instruments) before consummating the purchase.
Last but not least, beware "sextants" from South Asia. Many are on Amazon simply listed as "Sextants" but they are decorative objects, not true sextants.
From: Greg Rudzinski <NoReply_Rudzinski@fer3.com>
To: luabel@ymail.com
Sent: Tuesday, November 8, 2016 4:08 PM
Subject: [NavList] Best Budget Sextant for Novice Celestial Navigators
The beginner celestial navigator needs a sextant that gets the job done without breaking the bank. The following are the budget options and my grade:1. Davis MK 3 ... C2. Ebbco Special ... C+3. Davis MK 15 ... B4.Used metal sextants from Indian ship-breakers (Ebay) ... AThe Davis MK 3 is the cheapest sextant and can be had used on Ebay for $20. They have the very minimum of features and a vernier scale that could spell trouble for the beginner who transitions to a metal micrometer sextant. For piloting this sextant does get an A.The Ebbco Special can be found for $45 on Ebay but expect the Sun filters to be ruined. Replacement is not difficult but most likely beyond the skill level of a beginner. This sextant is great when traveling through airports. Light, compact, and airport X-ray friendly.The Davis MK 15 does everything a metal sextant does at the expence of an acceptable reduction in precision. $150 new or half that used. This sextant is the best option if traveling through airports to meet a vessel as crew or passenger.The most interesting budget option can be had from ship-breakers out of India. Ebay has some very nice examples to choose from with the best buys beiing those sextants that for some reason are missing a scope ($200). A sextant without a scope is still functional so these offers are the best buy IMHO. A beginner can add a scope at a later date if the CN hobby takes hold.Greg Rudzinski
Attached File:
