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Rainer

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  1. As far as I know CEM 120 can not be retrofitted to CEM 120EC or EC2.
  2. Hi John, No, I am not wrong and BTW there is no dealer of iOptron in Mexico so I have been dealing directly with the poor iOptron support in Woburn, Massachussets, USA. ! and Good for you and consider yourself over all very Lucky. There are many cases of iOptron CEM 120EC or EC2 mounts which do NOT work. So do not try to cover up the Sun with a finger. You know the stories very well ... have a nice day ... 👍
  3. Biggest problem is the newest firmware is introducing a periodic error with +-90" arcseconds and it can nor be guided out do I need to use an older firmware and that one does not correct the SDE of the encoders ... SDE = Sub-divisional error ... and iOptron does NOTHING ! Newest firmware dated 191120 Old firmware ( the slight drift in RA = horizontal is normal )
  4. Intelligent decision. CEM 120EC and EC2 still are plagued with encoder problems and that is going on for more then a year. Ask me why I know it. I have two of these CEM 120EC2 paperweights ... and no money to get something decent but that is my goal for next year.Scrap the two CEM 120EC2 and get another reliable brand.
  5. Hi, A GoTo command with this mount will always use the MAX speed. More then a year ago several owenrs of CEM 120XXX mounts suggested to iOptron to add a menu feature to set up this speed. No reaction from iOptron.
  6. Hi, I can not say anything to the size but as you mentioned CEM 120EC2 I would think it twice to take the EC2. If you decide to do it get a guarantee that it will work with EC2. I have two of them and It started all very nice but at full load it does not eprfomr as expected ... and iOptorn is doctoring with firmware since I have them. With encoders I would rate capacity down to maybe 80 to 90 lbs MAX! and not 115 as they say. I got my mounts in April 2018 and since then I have tested for them 16 firmware versions in 20 months and still I do not see the Silver Lining on the horizon ... I am at the max load of 115 lbs and it just does not work out ... I just wanted to warn you so you do not wlak the Road to Canossa as I am at the moment ... Yes I was very enchanted but now I am disenchantent 🤔 regards Rainer
  7. Interesting and OK I accept your point of view. We are talking heere of worm and worm wheel gears which most of the time have a speed of 1 revolution in 24 hours. Backlash in our case is more annoying then any friction and wear we will have all over the time we use our mounts. So as far as I know there are some " Premium " mount producers which do lap the worm against the worm wheel. They do not adjust the gear for having backlash. 🤔 I used to have two Losmandy G11 and had too adjust the worm gear at night after having adjusted it for Sun imaging and that is a total NO NO. So I made a custom floating worm with springs and since then I did not have to adjust them anymore. I also lapped my worm and worm wheel. The newest mounts from any brand are now using spring loaded worm assemblies pushing against the worm wheel ¿ why ? But OK, we can adjust our mounts as we think we need them, but my problem is now that I can not adjust my mount to have backlash Have a nice week 👍
  8. Great explanation except the famous slight imbalance is only necessary for mounts with backlash. When you have a mount with no backlash then slight imbalance can even develop to be a problem.
  9. None. The motors do not have much to do when it is very well balanced. I do not say perfect as perfect balancing is nearly impossible. It gets critical when you do auto guiding and need to move it fast for- and backward and there is where the Magic of the " Moment of Inertia " gets into our way. When setting guide commands very often then the mount can get into a resonance state and you will never get it out of it due to the pendulum effect ... And so we get now into the discussion of many more variables but this is not the main topic of this thread ...
  10. I took some images of my other set up but it is the same game. As you can see the heavier side e.g. the two Takahashi scopes are nearer to the center line then the AstroTech 8" RC
  11. No Problem. That is correct. And the balance there you achieve with the method below. Sometimes it is easier to balance a side by side set up as you have the freedom to move the assembly left or right and so find the correct balance when the CW shaft is vertical. Somewhere I recommended to make a simple side by side set up e.g. turn the DEC saddle 90° and even if you only have on scope then you have the freedom of sliding the scope left or right and so get vertical balance ... That even gives you the freedom to have you accessories in the orientation you like best ... So you balance first with CW shaft horizontal. Then you put it vertical and move the scope left or right and then, I do it that way I balance the DEC axis. Simple as that. Many people say balancing side by side is a 3 axes balancing. Well yes, but a normal scope set up also needs that either by adding weights ( 3rd axis) or by rotating until the whole scope weight is 50/50 over the vertical axis e.g. CW shaft ... Balancing means I have always 50/50 of the weight of each side of the rotation axis. RA has a rotation axis and DEC also has a rotation axis.
  12. This sounds like you do not get it balanced. Can you post some pics ? And now that I am writing this yes it is possible that when you have balanced in horizontal and you put it in another angle that you setup could move to some side. You can check this after having it balanced in horizontal and then put the whole set up in vertical position, If it stays there then you have it well balanced but if it starts to move to one side that means that you have an asymmetric weight distribution on the telescope side, which could be a finder scope, or a motor focuser, ot the filter wheel of the camera, etc. or whatever. if you see this then you have to add some weight on the opposite side to which it moves or rotate the scope in its rings, if possible, to get a symmetric weight ratio through the vertical line. Once you made that you will need to check balance in horizontal position again. You can even have an asymmetric balan on the counterweight side just by putting the knobs for tightening not directly over the shaft but to one side or the other ... of course it depends on how well or easy the RA shaft rotates. If the mounts has ball nearings then this is easily measurable. If there ar no ball bearing then this can be a source of stiction and balancing gets difficult as the stiction can hold up some wight distribution.
  13. Yes that is correct. Once you have balanced in horizontal the Center of Gravity will remain the same for both sides ... The length of the lever arm is equal to the position of the center of gravity and so in any position it will remain without moving. In the moment you have done it in real life then you will understand it.
  14. Look here at one of my mounts and yes that is most upper position of my counterweights as if the RA runs the most upper CW passes with a clearance of 1 mm from the mounts body. If I take off one of the 12 kg upper counterweights everything would be at the lower end.
  15. No, that is not correct as the center of gravity has to be the same ... I have 54 kg of counterweights on my mounts but know that my equipment just weighs maybe 42 or 43 or 44 or 45 kg and it is perfectly balance out with 54 kg of counterweights ... ¿ why ? Very easy 54 kg counterweights at let me say at a Center of Gravity of 35 cm will perfectly balance out 43 kg at ~ 44 cm Center of Gravity. Lever arm law ... as I posted a link above
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