Directions and Drift Alignment

I adjusted the eyepiece reticle xhairs to match the movement of the
star with the buttons on my handcontroller. Declination presses moved
exactly along the N/S line and RA presses moved the star along E/W
line.

While performing a drift alignment, i observed the star's movement in a
north-westerly direction. Hoping that it would come back due to a PEC, i
waited but it drifted further north-west. Is this PEC or a mount that
is still requiring Azimuth adjustments?

The equipment was a Meade ETX125 while tube, 12.5mm Xhair illuminated
eyepiece on a Televue 5x powermate. All of this on a Celestron CI-700
mount

Can anyone comment?

-Vittal

OK, north and west drift indicate two things happening simultaneously. The west drift means that the scope drive is running slightly slow,ie, not keeping up with the sideral rate. The north drift means either the azimuth position or the polar angle adjustment is off. You did not say where the star was, so it is hard to determine which is off the most. There are several websites that give very good info on drift alignment. S&T has some info as well as the Astronomical League. Check their websites. Once you have done the drift alignment where there is zero dec drift, then you can tweak the tracking rate by selecting the sideral or king rate on your CI-700 drive controller. Once you get the ra to track correctly OTHER THAN the slight periodic error, then you "train" the pec and it will give a better overall rate. Be advised that on the CI-700 the pec only works as long as the power remains on and you don't change the drive rate or the slew rate. Doing either of those or powering off loses the pec training and you have to start all over. That is why most folks do the pec training just before starting a long exposure. It takes eight minutes for a complete worm cycle and then the pec replays all the corrections you input during the training cycle. After that, the amount and degree of corrections necessary are much less.

Walt

Vittal,

Here's the method I use.

http://www.aa6g.org/Astronomy/Articles/drift_align.html

Based on that method, the answer to your question is: you only adjust the mount to correct north-south (DEC) changes. If you see east-west changes you can either ignore them, or correct them.

I guess if you have *significant* east-west motion, something is wrong. I haven't seen that problem. (I did swap the RA and DEC motor cables once. That was interesting)

As has been mentioned, you should polar align before engaging PEC.

sf