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Hello all.??

I have a G11G that was new in August of 2023.? It has been a great performer.? I leave it outside all Fall, Winter and Spring under a 365 cover.? I have had fine results guiding my 130mm f/7 refractor. Overall very happy.?

I took it off its permanent home and travelled to an outreach event at our club this past weekend.? ?Some software issues meant my guider wasn't working, but I was just doing some unguided 1min subs for live stacking for outreach anyway.? ?I noticed later looking at the subs that many showed some pretty hefty tracking errors - oblong stars all the way up to 'jumps' where each star was doubled along RA with a little trail between.?

Even with good guiding, I have noticed a lot of nights where the RA error is 1.5-2x that of Dec.? I'm happy with the guided images, but I'm starting to wonder if an RA adjustment is in order?? ?Perhaps sitting out through all the temperature cycling has caused something to loosen or tighten up?? ?If I cold get RA tracking closer to DEC that would seem to be better.? I'm not sure if the mount ever did that - I was new to guiding at the beginning and didn't pay attention.??

So my question to you is - how do I know if or when to try and adjust that spring loaded worm gear???

Brian

I am in a somewhat similar boat to you with RA being consistently higher than DEC. I don’t mind because it’s below my resolution but I would eventually like to upgrade to a larger scope. But I digress, on to your questions.

First thing to do would be to run PHD’s guiding assistant and accept its suggestions, then do an unguided run for about 40 minutes. Upload your log so we could take a look at your PE curve. Your next steps will be based on that curve as there are many areas that could use some tweaking. You can also use PHD log viewer to look at your PE curve and there’s another program called PECPrep or something like that, it’s free and is very helpful in analyzing curves as it gives the reasons for the peaks. If you don’t feel like wasting a good imaging night, you can guide while imaging and then PHD log viewer will “deconstruct” the guide commands and build your PE curve. Very handy if you ask me :)

Lastly, sometimes guiding can be improved just by tweaking settings in PHD2. I’ll let others more experienced make suggestions in that regard.

good luck

jonathan

I am using an ASI Air, and have several guide logs from that from recent sessions.? ?Is there info out there on how to de-construct these guide logs in to the PE curve???

I never have adjusted the spring in over a year. Once I got it set for good guiding, I stopped touching it. I don't want to waste a good night playing with it in the field. The G11G is odd, Sometimes the calibration fails in PHD2, I leave it and get great guiding or rerun it and it's still great guiding. The Guiding Assistant reports different backlash every time it's run. Still great guiding.? The only thing I would recommend, based on lots of trial and error, is to keep the distance between washers of the adjustment spring at a length of 8.5mm. That's what Brian V. said it's set at the factory.? One less variable to contend with.? Was out this Saturday and guiding was great. My RA is always larger then DEC. Here is the Guide Log. As per your jumps, might be some dirt got knocked into the worm or a bearing when you moved the mount.

On Mon, Jul 8, 2024 at 01:49 PM, BBasiaga wrote:

Even with good guiding, I have noticed a lot of nights where the RA error is 1.5-2x that of Dec.? I'm happy with the guided images, but I'm starting to wonder if an RA adjustment is in order?? ?Perhaps sitting out through all the temperature cycling has caused something to loosen or tighten up?? ?If I cold get RA tracking closer to DEC that would seem to be better.? I'm not sure if the mount ever did that - I was new to guiding at the beginning and didn't pay attention.??

So my question to you is - how do I know if or when to try and adjust that spring loaded worm gear???

Hi Brian,

I would agree with Jonathan and others that you need to do some PHD2 runs for analysis since that is what this forum is used to working with. Hopefully you have a PC you can connect to your camera and mount and have the ASCOM platform and ASCOM drivers for the gear installed. Once connected go to the brain and the guiding tab. Uncheck enable mount guide output so you can so what your tracking looks like without corrections. Click on a guide star and try at least 20-30 minutes. Then try to open your guide log (not debug) in Documents>PHD2 with PEMPro Log Viewer and PECPrep and look for the common errors. Then you might get some better advice here - not sure if the ASIAir data can be analyzed in the same way. Or post your guide log here so someone can comment.?

Good luck,

John?
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Losmandy G11G2 on pier; refurbed Losmandy G11 with OnStep controller; SkyShed design roll-off observatory; ZWO ASI2600MM-P; ZWO ASI071MC; Sky-Watcher Esprit 100 ED with field flattener; Celestron C925 Edge HD with 0.7XFR, William Optics Zenithstar 61 APO; PHD2, Sequence Generator Pro and PixInsight user

I am using an ASI Air, and have several guide logs from that from recent sessions.? ?Is there info out there on how to de-construct these guide logs in to the PE curve?

Sorry, I missed that you were on the AAir, I have no experience with it so may not be of much help. However, if you manage to rescue the guidelogs it’s easy to get the PE curve from them. Just download PHDlogviewer app on your computer, open your log, on the main window choose the session you want to analyze (preferably a long one), then on the guide graph right click and select “analyze selected, raw RA”. In the new window select “frequency analysis” and you’ll get your PE curve. Slide the cursor over the peaks and the software will tell you the amplitude and period.

Hope this helps

Jonathan