Know your limits! Shooting at 200mm on a cropped sensor for 120 seconds brought me nothing but disappointment and trailed images. So... after a year of using the StarAdventurer tracker and being at times frustrated, at times very pleased, I ran some tests at various focal lengths and exposure times to illuminate the "zone of operability", at least for my unit.

• 100-150mm at 45s: 87% useable; for 90s down to 70%
• 200mm at 30s: 67%; for 45s only 40% useable

"Useable" here satisfied my taste of what constituted "round enough" stars when viewed at 400%. ImagesPlus outputs eccentricity data, a convenient metric that is suitable enough. For me that value was 0.47 or less.

Now of course one can add a small guide scope and use PHD2 software on a laptop to correct for this tracking error; it's up to you to determine the level of hardware, complexity/time to setup, and cost that suits your situation/mindset. On a friend's setup using a guider, we can readily do 2 minutes at 300mm.

Bonus discovery! Halfway through my imaging session, Josephine asked me where Polaris was on the "clock" utility, and upon checking, I realized that I was on the wrong side of the pole! But at 130mm, the polar alignment error was not noticeable compared to the tracking error! So, if you're shooting less than 100mm, don't fret much about pointing.