Hello All,

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This is my first post here, so hello to everyone! I've been following this forum for a while and have learned a lot from you all. I am looking for some help though, to improve guiding for my G11 for imaging. I purchased it new from Losmandy in April of last year, however I've found that I'm struggling to consistently get round stars. When observing the PHD graph during a typical session, it's not uncommon to see swings of 5 to 6 arc seconds while guiding (my setup is imaging at 1.37"/px and currently guiding at 2.99"/px). A lot of subs have eccentricity around 0.7 to 0.8 when measured in PixInsight. That being the case, I've been discarding probably over 50% of my subs, so I figured it was time to start trying to improve this. I suspect that I might have some mechanical issues in my RA axis, however it's entirely likely I'm doing something wrong and probably stupid. Any insight will be appreciated!

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To start with, I have followed the suggestions in the PDF "How to create a baseline for guiding results using OpenPHD2" and have attached my guide logs.

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As far as the basics go, these are the steps I've taken thus far to troubleshoot:

1. Setup and leveled the Losmany FHD tripod on flagstones in my backyard. I run the rig from inside the house, so there is no movement near the mount while imaging/guiding.

2. Balanced slightly east heavy in RA. Using 21 and 7 lb counterweights higher up the counterweight shaft to reduce the moment arm.

3. Secured all cables: I'm using a PrimaLuceLab Eagle and have all cables fastened so there's no snags. I'm running the Eagle power cable and ethernet cable to the Gemini along the front of the refractor and strapped down along the counterweight shaft. These are the only two cables coming off the Eagle.

4. Investigated differential flexure: Spaced out the OTA rings as wide as possible. I was using an Orion ST80 guidescope with some ADM 3-point rings on top of the Eagle for the past year. I had noticed some "slop" in the ST80 focuser and was able to tighten it, no difference in guiding. I replaced the ST80 about two weeks ago with a William Optics uniguide 50/200 and securely mounted with a dovetail clamp to the top of the Eagle, no difference in guiding.

5. Investigated periodic error using PEMPro: Followed the suggestions from Brian in the "Losmandy_PEC_Primer" PDF. PEC curves were recorded using a camera on the primary OTA, so no potential from flexure as if using a guidescope/cam. The recorded PEC curves were not consistent through worm-cycles, so needless to say, the generated PEC curve didn't help. I've attached PEMPro file in case this is usefl.

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I'm pretty much out of ideas on what else I can do to improve guiding in RA. Please let me know if there's anything I'm missing.

Thanks in advance,

Frankie

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