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 6–7 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

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

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: 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.

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.

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.

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

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.

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

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??

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.

I would agree with that, on my pier I do have the center bolt but also have 6 others spaced out further.

Just a thought…

The ‘Drawing Needed’ thread implies that the pier adapter is attached using a single bolt through the center 0.50” thru hole.
You might instead want to use 3 bolts through 3 of the various sets of (smaller) thru holes (3 points determine a plane…) which should provide better stability.

KW

Hi Ray,

That makes perfect sense. Just a suggestion: maybe you can implement in PEMPro a monitor that would detect a star that is exactly the same brightness for minutes at a time, over multiple exposures. You could then warn the user to adjust the settings, exposure time, check for a hot pixel, etc. During testing of PEC + L6, I saw a number of logs that contained that same saturated pixel level, so it's not that unusual.

Regards,

?-Paul

On Fri, May 3, 2024 at 06:14 AM, Ray Gralak wrote:

ecause in your log the star brightness values are all exactly 32767.00. When a star is saturated it can produce a large flat region of the same brightness which can result in an inaccurate star centroid calculation, thus the jagged graph.

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You mean to tell me this program has trouble chasing the centroid of an artificially bloated star that is already scintillating due to poor and variable seeing conditions and a mount with periodic error that also moves it? That doesn't seem likely at all.?

Jokes aside, this makes sense. From what I've seen, the mount has periodic error visible in the graphs and follows this pattern (somewhat M-shaped) for a number of cycles and then it goes what seems to be chaotic for a cycle or several and then back to "normal." I'm wondering if the smooth parts of the graph are during steadier seeing, when PEMPro might have more a shot at getting the centroid of an otherwise bloated star correct. There didn't seem to be any rhyme or reason for the jaggedness (exact part of the sky I was collecting data, length of time I had been collecting data, tightness of the gear mesh, temperature). My cables appear like new; my batteries are new or newer; I've used a variety of quality power cables; grease looks good; the worm and coupler appeared to be moving normally, at least visually, and things appear to be in a straight line when slewing; when not in use, the mount is stored in relative humidity levels of between 20-30% inside of a mattress bag on a pier with desiccant).?

I'm a little nervous to get my hopes up, but "user error stemming from thinking he is so smart he didn't need all of the detailed and easily-understood instructions provided with the software and available online," has been an accurate description of some of my behavior in the past. You were too polite to say that exactly, but I know myself. I'll report back.?

George

The second video suggests that the wobble is coming either from the adapter base to flat pier plate connection, or the flat plate to pier connection.

I think I’d take a close look at those connections around the flat plate. Maybe the plate isn’t flat, or something is giving the false impression that a bolt is tight when it’s not fully tight.
If you don’t have washers between the pier adapter and the flat plate, try inserting one at each bolt.
Good luck.

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