PEC Training

After all the hee-haw about getting SkyX to use Maxim for images, apparently I can’t actually use that to do the PEC training. Not sure where I had gotten that idea. So, fired up CCDSoft and used it to generate a trackiing log (with guider corrections turned off). 1 sec exposures, ran for 17 minutes or so.

Problem: there is a drift to the star, so it steadily drifts out of the track box. I don’t know how far out it can go – if it is out of the box, do we lose part of the image, so the centroid is calculated wrong? Or, does it actually “see” image beyond the tracking box?

So, when I load the raw tracking log into SkyX, I see


Raw Data from CCDSoft Tracking log

Hard to see the curve – Bisque picked some tough colors. The drift looks bad – don’t know why I would have this in the first place. When I hit the Fit button, the drift is removed and I get


Data after Fit button. Drift is gone.

Not sure what this means – do I have a net 6.6 Arcsec error? Or is the 3.3 correspond to the 4.4 pixel displacement on the axis, so I have about 2 racsec? I check the Last box “Periodic Error curve for TCS” and get

PEC curve for loading into the mount

Downloaded this into the mount. Turned on “apply PEC”, and reran the tracking log to see if I get better PEC. The raw data looks like

Raw tracking data with PEC running

Still a serious drift going on.

The fit data is now

Fit data with PEC running

Hmmm, it looks to me like the mount is worse with PEC running!

Repeat the process; also, I focus the star first. Now, the 3 stages look like:

Raw data 2nd time

Interesting, this curve is upside down from the previous one.

Oops – it looks like it is cloudy now – no stars showing up. To be continued next time….


Now, will the mount automatically use the PEC when it is turned on, or do I have to enable it every time?

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