Re: Mount "shaking"

Maxime Spano

Hi all,

So I went to the observatory yesterday.

The shaking was discrete but the mount was still not behaving well. It was blocked again while pointing low toward West.

The shaking was present in precise, ignore and cascade mode. However in cascade mode the star was almost constantly going up and down (i.e along the RA axis) like if there was backlash to compensate even if there is not (I didn’t find where was the backlash compensation in SiTech but I guess it’s there somewhere).

For the encoder, the number of ticks per rev, on ServoConfig  I read 15097436 for RA and 15038461 for declination. I found these numbers too on SiTech.cfg plus two other ones: AlScpTicksPerRev=12505200 and AzScpTicksPerRev=12595200. The 12.5 million(ish) is coherent with the number calculated according to what Jan indicated in his previous message (and I guess means Scope ticks per rev). For the 15 million(ish) I don’t know where they could come from and if the difference with 12.5 millions affect anything.

-I did some Test in precise mode:

Toward West (Leo const.): PRiERROR was around -90 while pointing toward the horizon but only around 5 when I was pointing away from it, when tracking it oscilated around +-5. SecError was around +-1

While tracking the RACur was around 3.3amp with spike at 4.5amp (lowest to 2.9amp) while DecCur was at 0.4amp

Pointing toward the horizon keep RACur around 3amp (it was between 2.8 and 6amp very variable), pointing away from horizon RACur was more around 4.5amp (between 2.8 and 6.8amp).

Another test with the telescope pointing toward South at 45° altitude (which is a position when telescope usually working fine, i.e no blinky ) showed roughly the same numbers for RACur.

I also did a video where we can clearly hear that the motor is not working smoothly and jerks. Telescope was pointing a bit low toward West and I was moving it with the handpad (I stopped the movement before it goes blinky)

I will contact Mathis too, to see if they have any tips to improve the situation.

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