Hello - maybe someone will have an idea what the problem is - I'm beginning to feel that perhaps it must be a faulty product.
I bought a new "Sky-Watcher Star Adventurer 2i Wifi Pro Pack" in the spring and after learning basics, I spent using it several nights in July shooting the sky (with my Nikon D600 camera and Samyang 135/2 lens). In many of my shots, the mount was "delaying" and couldn't even hold 30 second exposures. I thought it might have been due to poor declination axis balance - and anyway decided to invest in a guiding accessory (ZWO mini 30/4 guide plus ZWO ASI120MM Mini) for better accuracy, so I could work with longer focal lengths and longer exposures in the future.
I tested this setup last night, the guiding camera ran well as well as working seamlessly with the PHD2 on macOS. Unfortunately, the problem with the mount continued and so I was able to document it better also thanks to the ZWO guiding camera.
The Start Adventurer ran quietly, but the mount drive systematically lagged slightly behind the rotation of the sky. Always after some time (5-10 minutes) the motor started to run faster for a second or two, as if making up for the accumulated delay. This also happened during the guiding calibration in PHD2...
Occasionally, the assembly ran fine for a few minutes before it started to lag again.
What i believe i can rule out as the cause of the problem:
- Mistake in polar axis alignment. I know how to point telescopes from several years of practice at the astronomy observatory, plus Polaris stayed during the whole session (2.5h) exactly on the circular mark in the viewfinder of the pointing telescope (moving along its circle a bit over the time).
- Overloading of the mount. My combined equipment weighs about 3 kg, half of the nominal load capacity of Star Adventurer. In the end, to really rule out this as potential cause, I took everything off and left only the super-light ZWO mini guide scope on it - but even then, to my frustration, I watched the shifting stars on the PHD2 monitor (at this point, of course, I had the correction cable from the ZWO camera disconnected from the Star Adventurer)
- Low batteries. At the end of the 2.5 hour test operation, the battery pack (4 x AA) measured 5.3V. In addition, to be sure, I also replaced the batteries, but the problem re-occurred again.
- Entangled cables or other obstruction to the movement of the Star Adventurer's axis.
- An incorrect mode. The problem occurs both in "star" mode (when I tried to use the additional control from the guiding camera), as well as in the "App" mode when i control the mount through a mobile app.
- Finally, neither random wind movement nor tripod instability: the stars always made "dashes" in the same direction, and their steady drift in one direction was noticeable even on the PHD2 monitor - that is, except for those moments when the motor "caught up" with the delay and suddenly accelerated to a new position.
I am attaching a couple of illustrative pictures of the problem: the assembly, screenshots of the PHD2 at the moment when the motor was accelerating to a new position (the stars are visible in both the old and new positions), and the assembly "ramping up".
I'm getting quite desperate - this is not how I imagined shooting with Star Adventurer... 😕 Does anyone have any idea what this could be, or am I left with no choice but to advertise the device?
Thanks for any advice... 🙏