I have a CEM40 with iPolar.
According to PHD2 guiding assistant, I am off on polar alignment, the last three times it was 5, 20 and 8 arc minutes.
I have not done other alignments like drift -- I know they are available, this hasn't reached the top of the stack until now. But last time out I took a LOT of time with iPolar to get that plus really centered in the circle, and I left it running until I started imaging and it stayed centered in the circle. Then GA said it was 8' off.
I have (though it was 2 times ago) recalibrated the center of the iPolar camera per the manual. I do not do that each time. It's supposed to be once and done unless you put in new firmware.
I've read a few older threads suggesting it should be accurate to 1' or less. I also found a brief comment about comparing to PHD2 and not getting good comparison but no real info.
Should a three minute guiding assistant run be accurate? Should I trust it more?
Next time out I'll do a drift align for comparison, but in the meantime so I have things to check -- what can throw off iPolar?
In particular, does the alignment of the guide scope matter (i.e. if it's not perfectly parallel to the RA axis, I'm not talking more than a few degrees, I just have not tried to make them perfect as my guide scope has plenty of FOV).
A slight twist on that question is does it matter for PHD2's determination during Guiding assistant of the polar alignment accuracy?
Other than doing a careful drift align to see which is right, anything else I should plan to check the next time out -- if the clouds ever part again?
Edited by Linwood, 23 September 2020 - 03:51 PM.