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Originally Posted by rogerg
I don't see that it should rely on tripod/pier level at all - the fact is you could have a level in the tripod knowing how "off level" it is, this could be taken into consideration quite easily I think.
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Mine has a level built in. If I level the tripod both e/w and n/s with a bubble level, including rotating the level 180 deg to even out any error in it, and then look at the built in level, the bubble is outside the centering circle. That can be corrected simply because the error is on the n/s line. I don't know what would need to be done if it was ne/sw.
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Interesting. I don't have an iPHone to test it, but I thought if magnetic interference would be a problem then the electronics, battery, metal in a device like an iPhone would have the same effect as reo, if it did affect the type of compass used in such devices?
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How accurate do you think the iPhone compass is? I would expect it would do for finding your way around when you are in effect using it as a GPS. My GPSs will all tell me which way is north, but only if they are moving and can work out the course I am on.
The fields induced by the electric currents are small are unlikely to matter. Any magnetic compass is affected by any magnetic materials around it. A fixed compass on a ship can be compensated for the metal in the ship. A portable one can't. You can never tell what will be close enough to affect it.
The iPhone level function has more chance because gravitational variation is much less, assuming a non-accelerated frame of reference.
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Originally Posted by bartman
It's a Meade ETX-LS. According to the article in Sky at Night Magazine - November 2009 - it takes about 10 mins to align and keeps objects in the 'eyepiece' for up to an hour.
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It is also an alt/az mount, so it is the same set of motors to align and track. The GPS tells the software where the mount is. The CCD lets the software work out where it is pointing.
All in all I don't see it as economic for an equatorial mount.