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Re: Toothy/Jagged Guiding with PEC

 

Thanks, folks. I wasted money on a new gearbox and RA cable all because of your suggestions.

I couldn't be happier. : )?

If nothing else, it confirmed an upgrade to a Titan RA axis would be money well spent for my C11 Edge. A community of folks helping out with issues, including user error, is pretty spectacular.?

My mount behaves absolutely normally when the star brightness values are under control. I used values between 5,000, and 15,000 here.?

Wasted money joke aside, thanks to all of you.?

George


Re: G11G Wobbles

 

On Wed, May 8, 2024 at 03:33 PM, Russ wrote:
With regards to the RA extension for the G11G, there are 2 adjustment/lock bolts on each side of it. I assume these are the only items that need to be tight???? I do see 4 other bolts on the RA extension and I have checked those and they are extremely tight. Just trying to narrow down this whole wobble thing.
Yes. There are 4 Allen head screws under each part of the RA EXT sides. These don't need to be crushingly tight - 2 to 3 ft-pounds should suffice. In many cases you are tightening a stainless screw into a threaded aluminum hole which you don't want to strip. The RA EXT halves fit together like a glove, so I would doubt there's any play there.

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


Re: G11G Wobbles

 

Just a gentle reminder (trying to help, not annoy¡­) that ¡®the screw is tight¡¯ doesn¡¯t necessarily mean ¡®the parts are tight¡¯. A too-long screw can bottom-out in a threaded hole and be tight without bringing the two parts together to make them tight. Thus the screw can be tight and allow the parts to rock back and forth.
Good luck.
-KW


Re: G11G Wobbles

 

With regards to the RA extension for the G11G, there are 2 adjustment/lock bolts on each side of it. I assume these are the only items that need to be tight???? I do see 4 other bolts on the RA extension and I have checked those and they are extremely tight. Just trying to narrow down this whole wobble thing.


Re: Guiding Comment and Question RE: L6.2

 

Dan,

After doing the upgrade, absolutely you need to rerun PEMPro and recalibrate PHD2. You are monitoring the number of steps differently and more than likely are out of sync with your previously PEMPro curve.? You should be able to simply update PEMPro to the latest version in the Help menu if you have the paid version. After I slew to the south and do a PEC curve, I do a second data acquisition run to see if the peak-to-peak distance has been reduced (or doubled if the curve is not inverted correctly). Since you're in that part of the sky anyway, running a PHD2 calibration curve, is just one more small step.

Best of 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


Guiding Comment and Question RE: L6.2

 

OK... so I believe I have upgraded everything required for the L6.2 upgrade.? I installed the L6.2 firmware on the circuit board, updated the HC to latest, updated Gemini driver to latest, update ASCOM to latest, and flashed my servo chips with the PIC kit with the latest .hex file.

I'm running an Edge 14 on a Losmandy Titan mount, using an ONAG, so with the 0.7X reducer, my guiding F/L is 2737mm.?

After the firmware upgrades, I tried getting away with not having to re-calibrate PHD2..... no way.? So, I started re-calibrating, and the first few attempts wound up in failure.? But, I wasn't seeing movement of the star for each calibration step.? So.... I increased the number of pixels per step, saw movement, and got a pretty good calibration.? The number of steps per axis were both in the teens, expected rates for both RA and DEC were extremely close, and orthogonality was OK.... previously with L5 I had a calibration of 1.0 or less, this time I got 2.9.... the axes looked perpendicular to the naked eye, but the value was a little high.? I can probably try again and do better for orthogonality.

But, my comment is that for each time I ran a calibration, and it was probably more than 5 times, the plots of the steps were exactly on the axes.... no deviation.? Makes me kind of wonder if that relates to the encoder resolution improvement.

My real question is this:? I recently ran PEMPro with L5, and uploaded a nice PEC curve to the mount.? My thinking was that the gears have not changed with the L 6.2 upgrade..... so would the improvement in encoder resolution necessitate my re-running PEMPro, or it would not make a difference??

I do have the newest version of PEMPro that handles L 6.2.

Thanks so much.

Dan??


Re: G11G Wobbles

 

On Sun, May 5, 2024 at 07:41 PM, Frank wrote:
Their cup like design and spring steel material may not fully compress to give maximum surface contact/friction.? Their sharp edges coupled with joint movement may carve out adjacent surfaces.
This is not the case, Frank. I've been using Belleville washers for years. They compress at 6¨C7 pounds of load and don't go any further. They do not have sharp edges and don't cut into any surfaces, especially the surrounding steel flat washers I suggested. Once the knobs snug up, you have all the torque you need to keep the mount in place. There is no need to tighten any further to gain mount stability and lock ALT/AZ into position.

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


Re: G11G Wobbles

 

I assume the 4x means 4 bolts? I have not heard of a 4x Hex Bolt? ? :-)


Re: G11G Wobbles

 
Edited

Thank you gents for the advice. I just ordered nylon washers from Amazon and will place them with all the screws on the G11G various tubes (RA extension...etc). With regards to the 4x Hex Head Grade 8 Bolts; anyone know the length? Only asking because it is pouring rain here and when it stops, I'll take a trip out to the observatory and measure the bolts, but just curious if anyone knew. Really appreciate all the help with this whole thread!!

I added?Belleville Washers to all 6 adjustment bolts on the AZ/ALT adjustment knobs on the G11G.? These belleville washers were sandwiched in between stainless steel washers so hopefully that will provide some additional help.


Re: G11G Wobbles

 

Re: Belleville Washers

Their cup like design and spring steel material may not fully compress to give maximum surface contact/friction.? Their sharp edges coupled with joint movement may carve out adjacent surfaces.

Another point I will make? is that what appears to be an accessory shelf is being held by one of the three button head screws (maybe more) there could be movement in between that connection.
A work around is to use stud+black nylon washer+nut tighten that and then add the shelf and another washer+nut.


Re: G11G Wobbles

 

Hello again,

If I had to firm up this arrangement I would add black nylon thick washers on the three MA bolts and the three Pier Extension bolts as there is very little mating surface between their flat Button Heads and the cylindrical mating surface.? (If there is improvement, then go for the Grade 8 fastener suggested below, don't forget the suggested washers)

In addition, I would place 4x Hex Head Grade 8 Bolts at the ALT Lock and Pivot points each with Black Nylon Washers. As your first post mentioned, you noticed improvement by tightening these button & knob points.? With the hex head bolts you can wrench/socket tighten them.? Be sure to use strong grade 8 bolts.? I believe that those mylar white washers (alt pivot) may allow movement.


Re: G11G Wobbles

 

Attached is a pic of my mount showing the adapter connection to my pier plate, the RA extension tube and then mounted to my G11G. I have verified every single bolt on the adapter plate, the RA extension and the RA/ALT bolts on the G11G are all tight!



Re: Drawing Needed

 

I added Belleville Washer to all 6 adjustment bolts above (in my 2 images) sandwiched in between 2 washers each. That wont solve my wobble issue but is a good tip to do.


Re: G11G Wobbles

 

Russ,

You are probably going to have to start from the bottom of your pier and look at every connection for play. Some connector which appears tight could be creating a gap when load is applied downward. I have 2 G11's, one with Gemini 2 and the other with the OnStep drive system, that I place on a single pier and neither one displays any movement like you're showing in the video. There are also internal bolts inside the G11 that attach the base plates to the mount head that could be loose, but that seems unlikely in a newer mount. You'll may just have to use process of elimination until you find the offending component.?

Best of 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


Re: G11G Wobbles

 

I have my G11 on the HD tripod in my living room right now, I will have it on my permanent pier soon and I will test for deflection.


Re: G11G Wobbles

 

Can you post more detailed pictures of the pier adapter plate your MA adapter is bolted to?


Re: G11G Wobbles

 

I have a center bolt through the adapter along with an additional 4 bolts and I verified those are all tight. Question, if you were to apply a slight force to the top of your mount, are you also getting a wobble effect??


Re: G11G Wobbles

 

Both of my MA adapters are the bolted 2 piece design. Just bought one last Fall. How new are the welded ones?

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Re: G11G Wobbles

 
Edited

Hello,
As an old car mechanic, my suggestion to track down subtle movement would be to use your fingers placed on/across adjacent parts to feel for any movement while rocking the unit.

P.S.: Rocking the unit may have created wear/rub marks on mating surfaces look for telltale marks.

Add this to your investigation.? I have the Losmandy Adapter Base #MA.? It is the older 2 piece design.? Upper portion being a cylinder bolted to a bottom circular flat plate.? Later design has the two parts welded together.? Do check for movement between these two pieces.


Re: G11G Wobbles