QHY Polemaster Works!!!

I've been quietly grumbling about the guiding performance of my AP900 mount for the past few years.   It hasn't been great, but it has been passable.   For my seeing conditions, I can't really complain since we really don't get many nights below 2 arc sec seeing.

My total guiding error tends to be around 1.25 sec. on average.   The real issue is that my stars tend to be slightly oblong (eccentric).   Often times, my DEC errors are double my RA errors.  This annoys me to no end considering that the mount is perfectly capable of great performance.   How do I know?   Back in August 2014, Charles and I made our second visit to Van Vleck Bunkhouse in California.  Though I had setup the AP900 that was purchased in 2009 a few times, the Van Vleck trip was its first real imaging session.   It performed impressively with 3 min unguided images with perfectly round stars.   I was using the Explore Scientific 80mm f/6 with a .8 Televue reducer.   When I did guide, my total guiding error was around .3 to .5 with PEC on.    Very good.

My polar alignment routine was primitive and started with the polar scope for rough alignment.  Then I used a modified drift alignment method using the DSLR and the hand controller.   I had read about this online, then tried it as documented in some of my earlier posts.   It seemed to work okay, but sometimes, it just didn't produce good results.  I base this upon the subsequent guiding that ranged from .5 to 1.5 seconds total error.   The problem with all this is that polar alignment can take 90 minutes or longer.    Also, the "DSLR iterative" method takes a toll on the handpad buttons.

Only recently have I experimented with placing weights on the DEC to see if one direction is beneficial over the other.   I discovered that placing a little weight so the DEC is imbalanced toward the COUNTERCLOCKWISE direction helps the guiding.  Since I've been using dual-saddle recently, I can achieve the same thing by making the LEFT side (as I face north) heavier than the right.

But the biggest improvement has come from the QHY Polemaster doodad.   A few nights ago, I met up with Jeff at Wupatki to do imaging.   I had him help me do the "first light" on the Polemaster.   It was a little confusing but within 15 minutes, we had completed the routine.   The first target I guided on produced .4 sec total error!   As the night progressed the error ranged from .4 to .8 depending on where I was pointing. 

Last night, I went out and used the Polemaster routine on my own.  I got the same results again!!!  The Polemaster is a godsend.   Including the rough polar alignment, the total time to get excellent polar alignment has been cut to 20 minutes total.   Now, I just have to get PEC going again.