iPolar users: How long does camera calibration hold up?

[rickwayne]

Once my CEM70 ships (always assuming I'm not too old to lift it by then), I plan to do a little quantitative experiment on  iPolar calibration. Once calibrated, asserts the manual, one needn't shoot two images every time one aligns, it's just  turn on the iPolar, match dot to cross, and you're laughing.

I'd expect the vicissitudes of using gear in the field -- thermal cycling, if nothing else -- would eventually perturb the relationship of iPolar unit to RA axis sufficiently to require recalibration. But I've no idea how long "eventually" is. (As in,"eventually iOptron will make more mounts and you'll  get one, Mr. Wayne.")

So I'm going to record alignment stats every time out -- PHD's estimate of PA at least, a DARV if self-discipline wins over eagerness to get photons on sensors.

Has anyone done an exercise like this, formally or informally? What's your experience with how long your iPolar "calibration the camera", to quote the manual, tends to last?

[Shimrod]

29 minutes ago, rickwayne said:

Once my CEM70 ships (always assuming I'm not too old to lift it by then), I plan to do a little quantitative experiment on  iPolar calibration. Once calibrated, asserts the manual, one needn't shoot two images every time one aligns, it's just  turn on the iPolar, match dot to cross, and you're laughing.

I'd expect the vicissitudes of using gear in the field -- thermal cycling, if nothing else -- would eventually perturb the relationship of iPolar unit to RA axis sufficiently to require recalibration. But I've no idea how long "eventually" is. (As in,"eventually iOptron will make more mounts and you'll  get one, Mr. Wayne.")

So I'm going to record alignment stats every time out -- PHD's estimate of PA at least, a DARV if self-discipline wins over eagerness to get photons on sensors.

Has anyone done an exercise like this, formally or informally? What's your experience with how long your iPolar "calibration the camera", to quote the manual, tends to last?

I use my ipolar with a Celestorn AVX mount. The camera sits quite securely in the the mount and I don't generally remove it. I have not noticed any need to re-calibrate at all in those circumstances. I have only re-calibrated when I have removed it (to pack the telescope away for summer), and once for a long journey when I was concerned it might get damaged as it sticks out a bit from the mount.

[rickwayne]

Thanks! I've heard from at least two or three other people, in other fora, with essentially the same experience. That's encouraging!

Sigh. The iPolar app runs very nicely on my Mac, but it's sort of boring running it with no camera to connect to...