just saw a guy on flickr that appears to have a bad one… or is this v1 vs v2?
http://www.flickr.com/photos/latent0image/12099683875/
rob
That was me and it was version 2 of the iOptron SkyTracker. I ended up returning the unit since with about 90 arc seconds of periodic error it was only useful for lenses below 100mm (unless you wanted to reject the majority of you subs). With a 50mm lens (APS-C) you'd probably be able to do some captures between 30 seconds and one minute, but for anything longer you'd be limited to wide-angle lenses in the range of 18 to 35mm. Basically, I found that it wasn't capable of doing DSO work. It would be okay for wide-angle captures of constellations and such, but not much else.
I actually tried two different units, the first one had less periodic error (but still not great) but it stopped working after one day. The second one I used on several different nights and the tracking performance was consistently bad. If you search on the internet you'll find several test reports that all show periodic errors in the 100 arc second range (+/- 50 arcs), so it seems that a good number of these are really that bad. However, there are a few users that have shown results that suggest that some of the SkyTrackers can be used with lenses over 100mm.
The polar scope is really nice and mechanically the entire unit seems sufficiently sturdy, but there seems to be a pretty wide range in the quality of the tracking.
