Register | Login
Attackpoint - performance and training tools for orienteering athletes

Discussion: Moscompass for Southern Hemisphere(Australia)

in: Orienteering; Gear & Toys

Apr 19, 2011 8:33 AM # 
Dmitry_oz:
Is anyone aware if such thing exists? My research was not successful. I'm looking for model 3L

Dmitry
Advertisement  
Apr 19, 2011 8:42 AM # 
gruver:
Such a thing DOES exist. I traded some used ones after the World Masters in Oz.
Apr 19, 2011 11:03 AM # 
Hawk 3Peat:
Just received confirmation of my order for Moscompass 3L from INUS
Mäntysuonkatu 6 C
53100 Lappeenranta
Finland
Puh. +358 405732608 Fax. +358 5 4120850
E-mail: sergei.murskij@inus.inet.fi
Apr 19, 2011 11:04 AM # 
Hawk 3Peat:
And this was for Australia. So definitely southern hemisphere.
Apr 19, 2011 11:56 AM # 
andzs:
Maybe little offtopic but are these compasses any good ? My wife had Moscompass model with stable needle (I guess Model 3) for 2 or 3 years and then needle started to freeze and finally stuck completely. Probably we got bad sample but we lost interest in experimenting with them any further. Currently we use Silva Jet Spectra (~10 years in duty and still going strong) and Suunto Arrow 5 which also feels OK.
Apr 19, 2011 12:06 PM # 
jjcote:
I've been using Moscompass for about the last 20 years, and the only issue I've ever had with them is the tendency to develop bubbles.
Apr 19, 2011 12:55 PM # 
NSW Stinger:
Stick with SILVA.
Hawk08- that explains a few things...
Apr 19, 2011 1:34 PM # 
simmo:
OAWA Shop has them Dmitry - send me an email. They are around 1/3 the price of Jets - which are admittedly good quality but as you get older Rob you'll fall and smash them on a rock more frequently. I've done 2 that way in the past 3 years.
Apr 19, 2011 1:44 PM # 
Hawk 3Peat:
Paid $140 for a new silva 3 weeks ago. Got 2 moscompass for judy for $91. Dont think it has anything to do with the compass stinger!!
Apr 19, 2011 4:55 PM # 
erict:
Compass hemisphere explanation can be found at http://sportident.ca/archive/2011/04/19/compasses-...
don't know if possible to put pics here)
Apr 19, 2011 9:47 PM # 
Dmitry_oz:
Thanks guys and especially you Tony!

There are number of reasons why I want Moscompass(apart from admittedly they have good reviews etc.);
1) I returned to orienteering couple of years ago after not being in action for the last 15 years. At that time/place we only had base plate type compasses and I never had any experience with thumb ones. Times changed so did I and why not to try! So it is an experiment !
2) simmo was right - I smashed One Silva Jet already! It was during NSW middle Champs in Waggga Wagga. Next day I was supposed to be running Long and I did not have a spare compass. Luckily someone sold me compass. Lesson learnt well - now I have 3 and about to buy 4th :)
Apr 19, 2011 9:56 PM # 
Dmitry_oz:
Just a bit off topic. I was a bit sceptical about all this north/south hemisphere stuff before. Note, 99% of o-shops or even manufacturers(check Silva web site) don't even mention for which hemisphere particular model. Couple of years ago I went to Russia and took my aussie compass with me. When I tried to use it over there it wad hopeless! The needle just never settled and was constantly turning!
Apr 20, 2011 4:58 AM # 
tRicky:
I thought southern hemisphere models worked in the north but not vice versa? Simmo tried to sell me a northern hemisphere model for Australian orienteering - I wouldn't trust him :P
Apr 20, 2011 7:37 AM # 
simmo:
tRicky has since been supplied with the correct hemisphere model - not that it will help his orienteering :D

Silva compasses have a small MN or MS engraved on the housing - a bit hard to spot, but its there. The Moscompasses I've been getting have 'AU' written in ink on the underside of the needle.

(re tRicky: I did receive a shipment of N. Hemi Moscompass from a British supplier, because I didn't actually specify S. Hemi - assumed they would guess since they knew I was in Australia. I didn't realise until tRicky tried one, and then I sent them all back. The ones I get now are definitely S. Hemi.)
Apr 20, 2011 8:05 AM # 
mprg:
Someone told me once that this has something to do with the little weight on one end of the needle; in my Moscow thumb compass there is a tiny metallic dot on the underside of the red half of the needle, slightly closer to the tip than to the pivot point. I think this balances the needle for magnetic declination in Europe. I presume that if I took my compass to Oz then the needle would behave erratically because the little weight would now be in the wrong place, i.e. the needle would be unbalanced.

I'd be interested hear from any southern hemisphere Moscow thumb compass owner, is the tiny metallic dot in the same place as described above?
Apr 20, 2011 3:47 PM # 
jjcote:
The difference between compasses has to do with the fact that the magnetic field lines are not parallel to the surface of the earth (this is inclination, or "dip", not declination). The lines are horizontal at the (magnetic) equator, but they get steeper and steeper as you approach a magnetic pole. If you were standing at the magnetic north pole, the field lines would be vertical, plunging straight into the ground. So in order for a compass to work when held level (which is how we like to hold them), the needle has to be unbalanced. If you had a neutrally balanced compass and you were close to the magnetic north pole, the red end of the needle would be pulled downward and would drag on the bottom of the capsule (assuming this is a compass with a "traditional" style bearing consisting of a recessed spot that balances on a pin). So the needle is made with more weight on the white end, and everything is happy. Unless you're close to the magnetic south pole, in which case the lines tilt the other way and the extra weight is on the red end. Manufacturers have determined that five different weightings are adequate for most orienteering purposes.

Now, modern compasses like the Moscompass have a more sophisticated bearing that consists of two pins, one pointing up and one pointing down, and this should be able to take out the non-horizontal torque such that the balancing would be unnecessary. I don't have any personal experience outside of my home magnetic latitude, but I'm told that the Moscompasses do very poorly in the wrong location. It's not at all obvious why that would be the case.

Also interesting to note here is that modern racing compasses do not use a magnetized metal needle. The needle is made of plastic (lower mass means faster response) with one or two tiny rare-earth magnets attached at the hub.
Apr 20, 2011 9:37 PM # 
Juffy:
but I'm told that the Moscompasses do very poorly in the wrong location.
Hoo boy yes. We got some northern ones here by mistake, and they were effectively unusable.
Apr 21, 2011 6:08 AM # 
Eriol:
From my experience, being just one zone off is not a problem with a Silva compass. I have been using a MN compass in the middle east and a MS compass in southern Brazil successfully. You don't really need five different ones to be an international orienteer...
Apr 21, 2011 7:18 AM # 
gruver:
I think it's more variable than that. The behaviour of basic Silva compasses with an "ordinary" needle whose weight is distributed along its whole length, is merely to drag one end down when in the wrong hemisphere (or zone) and hence they might "stick". I have seen people orienteer quite successfully with these (baseplate) compasses by holding them on a bit of an angle.

The behaviour of fast compasses like the Jet when in the wrong hemisphere is quite different. They seem OK until you tip them slightly off horizontal, then they go crazy. I haven't worked out the physics but it seems quite plausible that this arises from the concentration of the needle weight close to the pivot, as JJ says.

Eriol, is your out-of-zone experience with a basic or fast compass?

Related issues: Silva balances for 5 zones. Suunto has only two. Moscow?

This discussion thread is closed.