Tech – Alignment & Guiding (Take 3) – Fail

We continued with our Hard and Software test regarding the telescope controller and the control PC. Since last test was quite successful (just the small problem with the guide cam and the pointing model) we didn’t expect much troubles ahead. — Oh man were we wrong!

First Fail

We tested the guide cam, a ZWO ASI120MM-S, previously and it worked as intended. It worked also with the actual control PC and its virtualized Windows.

As we tried to fire the thing up on the test site in Davidschlag, it suddenly didn’t work. The cam managed to acquire some images, but it randomly lost connection to the PC.

This was so often, that a guiding via PHD2 was simply not possible. PHD2 lost its guide star constantly.

We are now a little bit concerned  if the problem is related to the telescope control server. It seems that it s USB hubs are faulty and quit working when a lot of USB devices connected to them.

Second Fail

As already mentioned in Tech – The Telescope Mount, the friction wheels are quite corroded, which results in a quite bumpy ride for the telescope.

In our first tests this was annoying and caused position errors, but we were able to move the telescope to the positions we want.

But in this night, the ride was even bumpier, and constantly caused the SiTech Controller to go in “Blinky-Mode” — a failsafe mode which causes the telescope to immediately stop the movement. So this time we were completely unable to point the telescope to any position at all.

We were quite puzzled what happened, but after some thinking we identified the Problem: Temperature.

Our last tests took place in quite warm weather conditions, this one however was during a quite cold night (in comparison to the last test nights). This causes the metal of the mount to contract and therefore we ended up with different pressures on the friction wheels. This seems to interfere with the bad friction wheels a lot more than in warm weather conditions.


We now decided to stop testing and therefore disassemble the telescope and start with the refit and repair tasks. This means to update the telescope with new friction wheels, additional absolute encoders and motorized mirror/corrector shutter.

However, we obtained some nice images during the last tests, which we plan to present here in this blog and on our other social media channels during the telescope downtime.

If you like it like it 🙂 …

Of course we will keep you up do date on the repair tasks.


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