Ioptron Sky Guider Pro DEC Oscillating Error

Hi Tomas:

I've not used the guiding advisor, so I'm not sure I follow what's happening in the second image, but your first image looks VERY similar to how my Skyguider guiding graph normally looked, with the long wandering DEC patterns. Sometimes mine would wander right off the graph and I would check my guiding and see RA only for most of the evening. Sometimes the DEC would hold still for several 6-minute subs only to slowly wander away again. My PAs were pretty tight.

In the end, my stars were still mostly round when reviewing the subs - I was able to keep about 80% of my 6-minute subs. I upgraded to the William Optics base (best upgrade I ever bought) and I was sometimes able to keep 100% of my 6 minute subs, and I even stretched that to 10 minutes. If I'm being honest, I can't remember if the WO base improved the DEC oscillation, but it did happen nearly every night, to some degree.

The most important question is: how do your stars look? If your RA and DEC error balance each other during your typical exposure length (other factors like sample rate can come into play too) then this might be tolerable, or even unnoticeable.

I'm really curious to see if anyone else can chime in with the reason this is happening. Is the rig sinking into the ground slightly? Is the latitude slipping? Would really love to know.

CS,
Mark