Quote:
Originally Posted by SpaceNoob
Hi Greg,
I had a similar issue recently, somehow my PEC got all wacky and threw out my subs. I used the wizard in theskyX to refine my polar alignment and now it sais my error is 0" and 0" to the refracted pole. New PEC run via pempro showed no drift from polar misalignment, the new PEC resulted in +/- 0.2" corrected. I now have perfect tracking again. I'm assuming the constant nights of -6 here have probably contributed to whatever suddenly threw off the usual perfect performance I get from my mount. 30minute guide logs are a flat line and I had a few subs with 1.3" FWHM at 2.5m focal length.
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Quote:
Originally Posted by PRejto
Hi Greg,
I think it is a mistake to expect that T-Point and PEMpro drift alignment are going to "agree" very much on where to place your PA! There has been endless and heated discussion about this on the SB forum. If I have digested the discussion properly T-Point is making a mathematical construct of all the pointing combined with flexure issues of every setup and offers various PA recommendations based on what one desires to do. But, PEMpro offers great PA at just one sky location. (Dec=0, etc) So, it seems all PA Is a compromise. Patrick W. has said (perhaps reluctantly) that using drift alignment is good enough as long as one also uses T-Point to model the sky so that Protrack can do its thing. But, so is T-Point PA!! Of course, if you moved the polar axis when you ran PEMpro drift you've got to recalibrate into your large model to get it to work again! The recommendation is to recalibrate as a "portable mount." The other possible reason your new T-Point model didn't work so well is that maybe your polar axis moves, especially MA, might have not been as accurate as you thought. There has been much discussion about that as well and now are methods to move using fiducial stars to confirm accurate adjustments. So, you re calibrated after you made moves of PA?
Peter
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What are fiducial stars? Fixed stars?
I did use the accurate polar alignment once and it did work reasonably well.
I was getting round stars and then I noticed my mount needed more setup - the bolt on tripod legs bolts were not all tight and the mount plate needed a shorter bolt etc. Plus after that it needed to be relevelled.
I did more last night. I used T-Point again and got it close but not round stars. I did another 105 point model and got the report saying to do a very large lowering of the altitude. It wasn't right. I wonder if this tripod pier has some flex in it still. Not all bolts are as tight as they could be.
Yes I redo a full model once I change PA adjustments in PA.
I did the Pempro drift again. That got me reasonably round stars. Not good enough long term but good enough for one night.
The thing I like about Pempro is that drift is actually measuring the thing you want to eradicate directly rather than indirectly with Pempro. I have had great results with Pempro before though. As a contractor I always want the actual measurement over the planned or ought to be measurement. It saves a lot of errors from off assumptions.
Greg.