Looking for knowledgeable input recommending very precise marching / navigation hand-held compass.
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Looking for knowledgeable input recommending very precise marching / navigation hand-held compass.
If it was me I would look at a Francis Barker prismatic in mils.
Military grade compasses.
If you are not worried about precise accuracy(not really needed in general navigation) I would look at most Silva
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Silva a possibility, but interested in a bit more precision. However, while I have basic understanding of mls I don't see a mls scale on any of my topo maps; only degrees, minutes, seconds and conventional compass rose; therefore I am opting more to degrees , minutes, seconds and a compass needle that is properly adjusted to NZ declination. At least 1 degree accuracy preferred and suitable for in-field map work. The old ex army prismatics were not too bad, and Suunto OK to march on once a proper bearing was established, but to establish the proper bearing from map and compass rose in the first instance when in the field leaves most Silva's wanting I feel, unless there are better models available than displayed in the sports and yuppie shops. Any other references or pointers will be appreciated.
For most land based navigation you don't need a great deal of accuracy as most navigation is via streams and ridges. The compass is really only to give you a rough idea. Greater accuracy was required for surveying but that is all GPS based nowadays.
Somebody we know is a bit more fussy than that, so I am looking about :)
There are ways around it. I just might have to pack a protractor and square and ruler along with the Silva :)
You will only find mils on any map regarding declination.
If you want precision you use mils to navigate. Shooting bearings and back bearings it is far more accurate and simple.
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OK. Thanks for the input fellas.
As time in based on the location of the sun and moon, time can then derive Latitude, Longitude and heading. The hour hand on a standard 12 hour watch runs 2 times the speed of the sun. Using your watch set in GMT in stead of local time and knowing the the even minute of time the sun moves 0.25 degress, you get very easily caluclate you Longitude, and using you Protector or Sextant, align the Sun the Horizon together blah blah blah......
Or get a Suunto compass or a GNSS (note the GNSS systems use the same principle as above, this is why GNSS Time is so important).
Personally, I use a Casio watch with a inclination correctable compass. It does NOT use position buffers like most GNSS devices. Sunnto make good/better watches for this too.
The accuracy when you purchase one only a small part of long term accuracy. The three in picture a of similar age, yet the one on the right has been stored near metels for most of the time.
I have two compasses that I have been using for the past 10 years or so and are still trucking along fine. Both are made by silva.
The first is my back-up that I use when navigating primarily by GPS, it sits mostly in my back pouch with my med gear, it is the silva Ranger (in Mils) this compass has an adjustable declination so that you can use it for all that map work straight away at a moments notice, shooting and following bearings is fine with the lid acting as a sort of aiming device.
The second is my primary compass which is the Silva prismatic (Expedition) this is my go to compass that is always secured around my neck, once again it is in Mils the beauty of the silva prismatic is just that, it has the straight edge and dial bevel of the type 54 (great for plotting routes on maps etc) but has the added bonus of a viewing window to use it as a prismatic to get that super accuracy reading that some (not many any more) strive to obtain. When I navigate on compass alone then a protractor is essential and is always safely secured the center of my folded map.
Why Mills? well as many of you will know there are 6400 Mils to a circle compared to 360 degrees, it is simple maths to work out that there is roughly 17 Mils to 1 Degree. If you are worried that your map does not have any reference to mils, then work out your Magnetic Variation before heading out and convert it to Mils, job done. Once you go Mils you will find it hard to go back lol.
Yes I rate GPS units but it is paramount to have a serviceable map and compass as a back up at all times (which is the ranger for me). More often that not I meet people who only venture out with a GPS and many that do have a compass on there person admit to not knowing how to use the damn thing! I love maps and navigating so I frequently navigate via map and compass be it map to ground or plotted routes leaving my GPS to be the backup in the rear pouch. The fact is that carring a compass as a backup etc is not enough unless you know how to use a compass effectively and maintain this skill by practicing.
I am happy to help people out one on one if you are ever passing through the central plateau.
My 2 cents :)
Thanks for that Shooter. I have pretty near decided on a Silva expedition compass. If possible could you pm me please so I can have a further discussion with you before I purchase one? Thanks in advance.
Yep no worries.
I did a search for the francis barker M73 prismiatic compass , got to a USA shop , and they have this British compass listed under ITAR , which means they will not export outside the USA , unless you have state dept approval & export licence etc .
Its a bloody compass , not firecontrol system for a tank , so NOW a piece of kit that has basically remained unchanged since the Ye olde Pirate days , is a modern day weapon of WAR .
Just INSANE .
Nice compass thou
I would be interested to know how the compasses made for the Brit Army work down here , the reason I say that is I know Yacht compasses have a way of re-balancing them , when they move from say here to the tropics etc , also Silva has 5 zones for their compasses , depending on where you are in the world
Compasses can be made with the needle balanced specifically for the particular magnetic "zone" or made with a deep bowl and or special magnets and dampeners such that it may be used anywhere in the world. The latter generally cost a little more. It is not uncommon for compasses made for the northern hemisphere to be "sticky" or even jam, down here.
Interestingly, almost all the compasses I have examined specs for in the grades costing less than $150 have a limit of accuracy of around =- 2 degrees assuming you can read the scale and set it up rigidly. Realistically these compasses will allow you about +- 5 degrees which is good enough to march on when used in conjunction with a good contour map. Higher quality survey grade sighting and prismatics with half degree accuracy cost upwards of $150 and mostly well over that; commonly around $400+ for good quality survey hand held sighting compasses.
Silva;s made in USA or Canada are made in China and are rubbish, but genuine Swedish Silva are good. Suunto is excellent and so are Brunton. Prices per model vary considerably depending on who you buy from so it is worth shopping around.
A good protractor with imprinted map scales matching your up to date map is an essential bit of kit if you are doing any serious navigating.
Thought so , I am familar with the old prismatic compass , and have not seen anything to match it ever , its a shame they are so expensive .
I use the Silva Type 15TD-CL Sighting compass, graduated in mils, with adjustable declination. You crank in the current magnetic variation, using the brass key on the lanyard and then ...:
NO MORE MGA - mag to grid add OR GMS - grid to mag subtract!
N.B. You will have to specify ... Sighting compass with mils and adjustable declination. Yes it costs more BUT it is a great deal easier to use, especially at the end of a day.
Yep great compass, it is essentially the new version of the older Ranger (curved lid rather than square) that I carry as a back up and like you have the MV pre-loaded on to it to assist with those end of day or rapid setting of bearings.Quote:
Originally Posted by ZG47
I think the multiply region compasses work because, like a Yacht compass the "needle" can move on two axis, however a yacht compass is so large, it counter balances via gravity. The pivot of the needle for 5 zone compass is a lot more complicated. The cheaper compasses only spin like a watch as they are weighted for the region to counter balance the magnetic field... If you use them in another region they may potentially touch the housing.
I.E if you used a NZ compass in Canada expect problems.