Originally posted by normhead Since I've never used astrotracer and all my star shots have shown streaking everywhere I'm not the guy to help. If what you say is true, then I may have to take advantage of the extremely wide 14mm lens on the K-1 and just crop off the edges.
I find the old 500 rule for streaking not really working well with high res sensors such as the one in k-1. For me personally I find around 15-20s exposures work best with 14-15mm lenses. Which means I need to bump up iso to 3200-6400, not the worst thing with such highly rated sensor for low light, but I did like clean files that 1-1.5 min exposures with astrotracer can provide. I can live with some streaking at the edges, I was curious if there's a way around that (I've tried calibrating the GPS at the location which improved things a bit, maybe I need to calibrate it further).
The app I use (photopills) for calculating exposure time for astro has two settings - the old 500 rule, and for high res sensors. With old 500 rule it suggests 25-30s exposures, and 15s with second option.
Still beats buying astro mount for casual use although I am tempted to get one in future.