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Hi,

I dont understand, the image is no longer displayed and has been replaced by "May be an image of sky"

Have I done something wrong here ?

Thanks,

Carl

I don't remember where I found it (so I can't verify the accuracy of it), but this is a SketchUp (.skp) model of the G11 which I used for designing an automated slide-off enclosure for my rig.

There is a Losmandy titan group...but it kinda been not used much these days.
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Brendan

I am reluctant to do anything more than routine adjustments on a brand-new mount; I'm hesitant to even do that.? So far, I have gotten good tracking.? The mount is sturdy enough that if I simply get a good polar alignment, there are hardly any dec corrections, ever.

At the same time, I want to see how this develops.? Ultimately, if the current technology doesn't satisfy people, Losmandy will come up with some modification.

I see a lot of people making observations like mine, but (thankfully) nobody complaining that the G11 is unusable for astrophotography because of it.? If I start having serious problems with guiding, that will be a different situation than the one I'm in now.

You will find many threads with similar observations.? When I noticed that my G11S (before I added my DIY SLW) had a lot of backlash, I tightened it using the easily accessible adjustment screws.? Turns out, by doing so it then easily binds up when slewing - at least with the 3rd party motor / controller kit that I bought (the G11S has no goto).? The reason for this is that either the ring gear is not round, or that it does not rotate centered due to some other reasons such as play in the axes.? So, without SLW in order to slew there needs to be a good amount of slack.? In my case, as it was delivered from Losmandy, the slack was very noticeable and annoying in the FOV when just moving the scope gently back and forth.

The Losmandy SLW has a backoff screw that basically disables the SLW so long as the gear is below the worm setting as determined by the backoff screw.? Once the gear is engaged in the worm to the max due to whatever non-roundness, the SLW engages and there will be extra pressure from the spring - which seems to be quite strong.? That will cause friction and may have side effects (I don't know - for my DIY SLW I use weak springs that slowly engage but I don't need a backoff screw).?

Being practical, forgetting about the SLW, backlash in RA does not matter much for tracking so long as the gear is pushing (use a counterweight if needed).? For DEC, once you reach your target it won't need to change much.? That means that you can tighten it to reduce the backlash, just for that position.? When you have to slew again, loosen it so it won't bind.? Or you can live with slack in DEC and see if PHD2 can fix it - but it's not ideal.? These types of problems are quite commonly discussed here, and it is also my personal experience.? If you have the SLW, in that case you should engage it fully by turning the backoff screw so the worm is fully engaged without slack.? Or you can take it off and follow the above and see what works better.

While I don't have a Losmandy SLW myself, at the Grand Canyon / Kaibab Lodge star party I have adjusted one from a friend who had just received his G11G with all the trimmings from Losmandy and had horrible backlash.? I don't think this was Losmandy's fault, I think it happened because he did not know to disengage the clutches when transporting the mount.? As a result, huge forces occur that can cause the settings to be dislodged.? Fixing it was easy though.? We had looked at the Losmandy video on this and it's quite easy following Scott's instructions.? However, if your mount is like mine, you may need different settings at different positions of the OTA.

While Losmandy recommends to not change the factory settings, my experience is that you need to know how to change it when it is needed.? The Losmandy is made for DIY so I take advantage of it.? It is nice to have full control.? If it were me, I would try running without the SLW (by taking them off) and with the SLW, and see what works best.

THANKS SO MUCH CHIP! ?Very informative. exactly the kind of info i needed. I'm amazed the G11 only uses 5" including the MA adapter, but I've only see pictures and videos of it, never had my hands on one. I wish they had a 3D scale drawing on their website of it. I plan to only remote image and remote view from my warm house, but when I poured my last pier I was only planning to do visual, so I know how interests can change. Building it to accommodate either makes sense.

I went 36" deep with the last 36"x 36" block of concrete and an 11" concrete pier, topped with a custom 6" steel adapter and had I no issues that I detected, but was considering 48" deep this time with a 12-14" concrete pier just for overkill.

Assuming Titan motors are coupled the same way as G11 and GM8, another item to add to the checklist is that the Oldham couplers between the gearbox and worm are not slipping.
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Edward

Thanks, Brian.? I will monitor the situation and in particular look for improvement as the mount wears in.? Since this is Losmandy, I know you and your colleagues will be on top of the situation.

It did concern me that not only does PHD2 report large backlash, but also, it takes a very long time for me to nudge the telescope north or south at Guide speed with the hand controller.? In any case, we'll see what happens.

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Yes, the SW 0.77 FR has 2 adapters on it. Tonight I removed the longest adapter and will test everything with that Removed.? ?Unfortunately it looks like clouds for next few days so I cannot test.

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aughtago,

How high? An imaging camera doesn't care so much but your back and knees will let you know if you get it wrong. A Celestron EdgeHD11 is not huge but when you consider the possibility that you could? easily have over 12" of imaging hardware sticking out the back of the OTA not counting an external focuser or any cables the shortest pier height is not going to be all that short. If we start with?a Losmandy G11 I at a pier height of 30" from the finished floor to the base of the Losmandy MA mount adapter the mount will be about 35" high. If you are planning to image with the C11 your imaging train will be getting uncomfortably low anywhere near zenith and you probably do not want to be dragging any hardware or cables on the ground which would be a possibility with a sort 30" pier. It seems like a safer imaging pier height from finished floor to the base of the MA is probably about 36" on the short end which puts the mount at a tic over 40" and provides some future flexibility in imaging options.

If you plan to use the EdgeHD11 visually you gain about 10" or so without all that hanging off the back of the OTA. I'd suggest nothing less than 42" depending on how tall you are. At 42" the mount is actually sitting just under 47" or so. Low enough to not need to be on tippy toes for horizon hugging objects if you rotate the diagonal but still high enough to be sort of comfortably seated for observing at the zenith. Slightly taller is a plus as you will not be giving your knees as hard a workout and for taller folks 46"-48" is not out of the question.?

If you add other popular scopes lets say a typical 130-140mm f/7-f/9 refractor you will need to use an even higher pier to observe comfortably at or near the zenith. My favorite visual scopes are the bespoke Parallax/AT130mm f/6 apo and the slightly longer 100mm f/9 Takahashi FC-100DL apo. For visual use with these OTAs I usually have the tripod height set to about 44" or about 48" mount height. Which is also where I used to set the tripod for the C14 with the G11 under it.??

The other things to think about is that visual observers take up a lot of room around a scope. The longer the OTA the more room it and the observer needs around the pier. Taller walls provide much better wind protection and reduces OTA disturbances. If it is cold where you live or you like to not be cold a standalone warm room to operate the scope imaging sessions from will be a plus by all? accounts. isolation of the floor and pier foundations is really important, you cannot walk on the same floor as the pier is poured on! Frost depth is something to know if it snows or freezes at your location. Do not believe the freeze depth charts, by digging 12" deeper your telescope pier will probably still be plumb in 20 years. Build your pier foundation upside down, put the largest width on the bottom and use Sonotube for the main pier base set 6" above ground height, use rebar from the base and up the pier and tie them together. Use quality 12" S.S. L/J-rod anchors in a 1" plywood form to hold the rods accurately in place during concrete cure and take the time to finish the foundation top level and flat to minimize the need for shims when installing the steel pier. If pouring a concrete floor pour it after the pier foundation has cured. Use a perimeter footing to help stabilize the pad and leave a 1/2" gap around the concrete pier and poured floor, once all are cured fill the gap using a soft flexible expansion gap foam.? ? ? ? ?

Just some thoughts.

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Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?

Hi Andrew,

Where are you located? I'm in the L.A. area and would help if nearby. If not maybe there is a Losmandy user_group member nearby who would meet to help you. We are a pretty active group and members here often go well out of their way to help a fellow Losmandy user, especially if it is going to help a larger group like a class of students.??

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Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?

Hi Russ,

Now that's weird. I'd call and ask SW about it, maybe there were some out of spec reducer/flatteners or out of spec lens cells. In any case well worth asking, they probably know how to resolve this issue.?It is odd that I have seen it used this way with a DSLR and the images seemed to be well corrected. Maybe I needed to pixel peep on a large computer screen, when zoomed in on the camera LCD the images looked good. This was a while ago maybe eight or nine years ago on a then new Esprit120 apo using a Canon EOS5D but AFAIK not much has changed.?

Sorry I did not help you much.?
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Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?

I have my setup exactly has my photos above (but in case of the photo above, my distance is about 51mm behind the spacers that came with the FR).? I have to use 51mm because if I add spacers to get to 56mm, I cannot obtain focus because the focus tube on the Esprit is all the way forward reading 0).? My configuration also matches what ZWO shows for proper spacers with the ZWO Filter Wheel.? I'm am TOTALLY lost why this is such a problem and was hoping to see how others have resolved this.

I just Googled the Esprit 120 manual and it is as I recall, I'm not loosing my marbles yet!? Is this how you have it setup??










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Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?