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Ryan,

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Thanks so much for your time looking at this and your observations, it definitely gives me a starting point of what to look at. My current plan is to adjust what I can with the mount as it is (steel worms, original worm blocks, existing grease etc) to see where I can get to. Hopefully this will then give me a good (and improved) baseline before I dismantle, re-grease, install new worms and one piece worm blocks with Belleville washers. I’ll also look into whether replacing the oldham couplers is feasible too as getting them in the UK might be tricky? Hopefully after all that, and correctly adjusting everything, there will be an improvement?

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Then it’s similar again with my ageing G11 with an Ovision RA worm. The difference this time being that I don’t currently have any upgrade parts, so it would be adjustment and re-grease only.

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I forgot to mention that I polar aligned with a polemaster (first ever time doing it), so will look at that again and also confirm alignment with NINA 3 star PA. (Also never done before). I might also try another first of drift alignment just to get the best baseline I can! At some point, I might actually get some imaging done!

Thanks again and any more advice welcome.

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Bryn

I re-read that you already have the brass worms in hand. Curious what a measurement with those in would look like. I'm curious how much improvement others have seen as they transition from steel worms to brass. I've only had the brass ones.?

Bryn,

Nice work. This is not a simple process to navigate but I think you are doing fine. Toward the bottom of Michael Herman's instructions he goes into how to interpret your recorded guide logs. I went ahead and loaded yours into PECprep and took a look... your raw guide log showed a little polar alignment error, which is why the DEC and RA lines sloped up. While you want that to be as accurate as possible, as far as I understand it, that is not a show stopper (my feelings won't be hurt if someone needs to correct me).

I used the focal length you gave (360mm) and made an assumption on the pixel size since you labeled the file ASI1600. The screen capture above is what I saw after I clicked "Auto Filter" at the bottom. This measured a "baseline" peak periodic error of your mount at +9.75/-9.57 arcsecs, while the average periodic error was +3.0/-3.64 arcsecs and the MaxRate was 0.36 arcsec per second... sidereal rate is 15.041 arcsec per second so this should be well within the capabilities PHD2. The next tab show what a generated PEC curve might look like if you loaded it into your mount. This is a little superfluous at this point, since we are just talking about recording a starting point, but it does give us some data, there are some large swings in your curve besides from your worm gear and it does look like your worm gear adjustments could be tweaked. I'm a newer mount owner (G11 with Spring Loaded worm and tucked motors) so the other guys out there with single piece worm blocks may have better experience conveying worm adjustment techniques.

Finally if we look at the frequency spectrum tab I see two large spikes. One is your worm drive and one is about 1/3 of your worm period. This may be an oldham coupler that needs to be adjusted? I'm not too familiar with the single piece worm, sorry... but it does seem like worm adjustment could give you the most bang for your buck.

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as far as comparison goes, I'll show you my own mount after I tweaked the oldham coupler, cleaned and regreased my worm/ring gear/needle bearings, and refined the spring loaded worm tension:

Period error got down to about plus or minus 1.5 arcsec with average error plus or minus half an arcsec.

PEC can cut that in half, which is pretty much what I see in practice, getting me to seeing-limited guiding. If the seeing is average, I can guide within 0.5 arcsec... if I get blips of excellent seeing it may drop to 0.35 arcsec for a little bit. Poor seeing is up near 0.8 arcsec or greater. Various blips on the curve are visible on the screenshot below. You can see that PECprep gives a little more detail for the G11 setting than it does for your G8 setting. That huge mountain to the right of the curve is from polar alignment error... it is a super long period error that you can pretty much ignore.

Basically I shared my PECPrep results so that you can see what is possible and see that even with small periodic error left over, you are still going to have some spikes on the graph.?

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Hopefully it gives you an idea of where to go from here. Try following the worm adjustment instructions until you can reduce that worm period and 3rd harmonic peak. From what I've heard from other folks here and there, your starting point is really not too bad, but there is room for improvement. There are of course mechanical upgrades you can accomplish, but I would encourage you first to try and maximize what you have first. When you accomplish that, if you still want to upgrade to a precision brass/ spring loaded worm you will have a newer and better baseline to compare that to.

Hope that helps Bryn, and I hope that someone out there with a one piece worm block can offer up some sagely adjustment advice.

Good luck and clear skies,

Ryan

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So, I have had my first attempt at trying to get a baseline. I followed the guidance above and produced the logs in the attached file over about 50 mins on a GM 8, with Zenithstar 61 at 360mm focal length.

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Even despite the explanations given in Michael's documentation, I have no idea what I'm looking at! Whatever it is, to me at least, it doesn't look good?

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If anyone could give me any pointers, that would be great!

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GM8, original steel worms and 2 piece worm blocks probably needs some TLC which is why I trying to get a baseline (I have new grease, brass worms and one piece work=m blocks for each axis to go in) before I implement upgrades.

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Many thanks

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Bryn

This could be either the 160 pr 200 extension?

thanks

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jim

I think I see now. The 200 is a pier extender, and the - 1/2” bolt goes through the extender bottom and MAL MA adapter, and a 3/8” bolt goes through the top of the extender into the ZWO Could I also do this with the 160 extender?

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thanks

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jim

Thanks, I am a bit confused (does not take much ?). I thought the MAL to MA adapter would attach directly to the Losmandy HD, and I would have a bolt come up from underneath that to attach to the ZWO AM5. I must be missing something?

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jim

Also check out the ADM "MyT Tripod Adaptor" for the G11 ().

It has a square plate on top designed for the Paramount MyT, but works perfectly.? It has a hole, threaded M12, in the center of the plate.? You will probably need the pier extension.? I use this with my Pegasus NYX-101.

Also suggest you get the ZWO pier extension as your scope will swing in much closer than a Losmandy at the bottom with the AM5 being a much smaller mount.

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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, NINA, Sequence Generator Pro and PixInsight user

I did just that. Works perfectly with no wiggle, very solid.

The center hole in the adapter accepts a 1/2” bolt. ?I drilled out the center hole in the base plate of the ZWO 200 pier (was almost 1/2”, little needed removed). ?A 6” long 1/2” bolt goes through the pier base, MAL adapter and into threads of the Losmandy HD tripod. ?A second bolt goes through one of the 2 oval slots in the 200 pier base and into a threaded hole in the adapter. ?I think it was 1/4”.?

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Appreciate the help and will try NINA Discord. I have tried the Restore Guiding and although it was not selected, it did not help. System ran great for 2 years but now after a Meridian Flip, the guider does not try to 'find new guide stars'. It still tries to track but it thinks it is on where the old stars are and does not update.

That would be worth a try. ?I have longer vids too and want others to see them on the hope someone can assist with the drift in the tracking. ?On the one minute video the station just starts to drift slowly towards edge of frame. ?SkyTrack offers tracking ‘adjustments’ but I want to make sure the baseline is as good as I can get it first then apply corrections. ?I’ll see about YouTube.

On Fri, Sep 13, 2024 at 11:59 AM, Bill Grogan wrote:

Anyone have any advice on video file editing or compression? ?I have several vids but I can’t post them do to size. ?My smallest is 85mb and is only 2 sec. ?Some type of compression needed? ?Edit into different format? ?Capture at lower resolution? ?I’m not a video guy! Ive worked on still photos since the beginning.

Anyone have any advice on video file editing or compression? ?I have several vids but I can’t post them do to size. ?My smallest is 85mb and is only 2 sec. ?Some type of compression needed? ?Edit into different format? ?Capture at lower resolution? ?I’m not a video guy! Ive worked on still photos since the beginning.

On Wed, Sep 11, 2024 at 01:49 AM, Ed Harp wrote:

Yes, with the RA horizontal for balance and great polar alignment, I am getting guiding at 0.4" most of the time.

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I have been doing a lot of this stuff before I found the page I wish that I had found it sooner! Look at the balance, clutch washer assembly order and orthogonal alignment tips and follow his examples.?

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https://www.wilmslowastro.com/tips/g11gemini.htm

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Let me know if you have questions.?

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On Thu, Sep 12, 2024 at 06:34 AM, Dnorton wrote:

At the risk of sounding like an idiot, I hate to ask a question that may have already been asked... I recently bought the G11 with Gemini 2 at Level 6. I promptly updated the firmware with the firmware update program.

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In the HC menu is a high-resolution tracking mode for RA and Dec. I have tried to find out specifically what that means. I cannot find it. Maybe I am stuck on the word "tracking". Is it high resolution for slewing from object to object or is it high resolution tracking for guiding during astrophotography? I've been out under the stars with the mount exactly twice and I did two nights of photographing the Cocoon Nebula. A total of 10 hours. First night I had it turned off. Second night I had it turned on. I couldn't tell a difference. Using the ASIair Plus, my guiding error was .25". If anyone can explain this high-resolution tracking to me, I would appreciate it.?

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Doug

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There are no stupid questions here. I do sometimes have a stupid answer...

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Hey, I'm an ASIAIR user and if you are seeing 0.25" guiding error you are doing as good as it gets. Your mount and PA must be very good and the seeing excellent to get those numbers consistently.?

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If you didn't buy the mount and Gemini 2 new from Losmandy you should verify the firmware versions. Go into the HC - Hand Controller - sub menu then select the "Info" screen and you will see the HC firmware version, Mainboard firmware version and the PIC chip firmware version. As I recall the current versions are: Mainboard L6.02, HC 1.61 and PIC version 3.?

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Thank you for the information, that really helps. Now I know to keep those settings on. I will check every time I turn the mount on. And yes, my mount is the new L6 and the chips have the updates. Thanks again!

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Doug

On Thu, Sep 12, 2024 at 10:38 AM, Dnorton wrote:

I have seen the check boxes for the RA and DEC 4x mode. By default each time they were unchecked. I had to check them to activate them. I assumed this was called high resolution mode. I don't have the hand controller in front of me at the moment.?