In my experience, cellphone compasses are completely unreliable for dialling. Some are off by more than 20 degrees. You can quickly check the accuracy on Google Maps: the narrower the blue cone is, the more accurate results will be.
Dan Uza On Tue, Sep 11, 2018 at 10:39 PM Steve Lelievre < [email protected]> wrote: > Hi everyone, > > How good is a cell phone compass? I mean, if I have no metal nearby and > I have the phone set to show True North, what kind of accuracy can I > expect if I lay my phone flat and use the compass app? > > I'm working on a vertical west sundial for a community garden (a.k.a > allotment) and have a deadline of end of September to get it installed, > because the aim is to unveil it at the group's annual meeting. > > The dial is to be installed on two posts. I want to get the posts lined > up as close to north-south as I can, to make aligning the dial easier. I > will use adjustable bolts to fix the dial to the posts, so can I > compensate for the line between them being a couple of degrees off - but > no more than that. > > I already have one post installed and concreted in place. I had hoped to > use the sun's meridian shadow cast by it to give me a precise line N-S > for placing the second post. Unfortunately, rain has set in here and it > looks as if there will not be a sunny day for at least a week. I don't > think I can wait that long to get the second post installed; otherwise > I'll be short of time for the other remaining tasks. Hence my interest > in using my phone compass for alignment. > > Cheers, > > Steve > > > > > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > >
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