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Rainer

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Everything posted by Rainer

  1. Hi Roland, Most people are likely somehow a bit lazy or do not want to disclose what they do. Of course the result can be the same. I only have EC2 mounts but from my former experience I can say. With encoder you mainly correct for drift and atmospheric refraction over a long period and perhaps the one or other sum up of seeing and a bit of rest PE. In reality it is not PE but it is more a summing up of different error and that is what you guide out from time to time but mostly drift and atmospheric refraction. Without encoders you add the PE for guiding out and that is compared to drift and Atmospheric refraction a quick changing error whereas drift and atmospheric refraction are a slow changing error and are constantly moving only in one direction. PE is moving backwards and forwards and even can have additional peaks or valleys overlaid over the sinusoidal curve. There are plenty of images of uncorrected PE curves and corrected PE curves in Cloudy Nights. iOptron delivers with each of their mounts plots of your RA errors be it non EC and EC mounts. Look at the images of the plots of my mounts. Rainer
  2. Hi, As they say 60 lbs carrying capacity and that means 60 lbs carrying capacity excluding counterweight. Counterweights are extra You can put 60 pounds of equipment on top and put 60 lbs of counterweights on the counterweights shaft or even more depending where the center of gravity of your equipment is. My mount CEM 120EC2 is specified with 115 lbs carrying capacity and I have 118 lbs of counterweights on it and no problem. but that does not mean that my equipment is also 119 lbs. My equipment on top is perhaps 105 lbs but due to the high center of gravity and the preferred way I put my counterweights for balance i get that combination. In the image you can see from top to bottom 3x 12kg, 1x 8kg, 1x 6kg and 1x 4kg counterweights (those ugly golden pieces ? ) which adds up to 54 kg ~ 119 lbs Clear ? Rainer
  3. Hi souls33k33r, I would say yes and if you do not like just send it to me in Mexico ... Again, encoders are not there for taking away the guiding in the way way as a car with an automatic lane reading and keeping from time to time needs to be corrected a bit ... I am sending a guide ping every 15 seconds just to correct drift in RA as well as DEC and that is it ... I am guiding through an OAG at 3203 mm focal length and my main interest are the Arp Galaxies ... I am not guiding with PHD2 but with Sky Guide from Innovations Foresight. PHD2 guides on one star. Sky Guide uses the whole frame of the guide camera ... More info below. I tested it for 60 days and that convinced me and yes even having encoders I do guide and if you want tog et into long exposure time like 10 min subs you will need to guide (even having encoders) as drift is going to ruin your images. I do 15 minutes subexposures on the faint fuzzies of Arp ... at an image scale of 0.476" arc seconds per pixel and guess what ... I do get round stars ? www.innovationsforesight.com https://www.innovationsforesight.com/education/full-frame-guiding-focusing/ Rainer I know I am a strange moth between all those butterflies still thinking that encoders do make guiding unnecessary ?
  4. What about all those happy guys with any mount brand ? They just do not post anything ... From 100 messages one is positive and the rest is complaining and whining ...
  5. and I have found a lot of horror stories too about every mount brand. A guy owning a 10micron ( just US $ 12,000.00 in the base model) mount is now without it since 3 weeks, had to ship ti for repair and the culprit is a defect of an electronic board and this electronic boards can only be made by 10micron ... If you base your decision on horror stories better look for another hobby ? Just kidding ... Rainer
  6. Hi, Right but encoders are encoders and it does not matter where they were built in. It is a question of carrying capacity what you are mentioning now. Encoders do not care about weight on the mount and they do not need to care about it. Encoders do correct the periodic error. Look iOptron has now 4 mounts with encoders and they are CEM 25EC CEM 40EC CEM 60EC CEM 120EC The encoders are there for correcting PE and they do it. No I do not have experience with an CEM60EC but a friend in Mexico has a CEM 60 and a CEM 60EC and he is happy with both. Of course he bought first the CEM 60 adn then the CEM 60EC. Why ? I have not asked him. If you stay in the carrying limits of each mount the encoders will work and if you put more then the limits the encoders will also still work trying to compensate anything which is moving the axis but then the mechanical flexibility will play a mayor role in the efficiency of the encoders and how well the motors can react to the correction signal product of the encoder correction. Again encoders do not care about carrying weight they only they care of the PE in the same way as the encoders in a car do not care the type of car anfdif it is a Limousine or a SUV when pout in for maintaining a constant speed on the M5 ... Again the big problem here is that people still think that encoders do magic and guiding get obsolete and I guess this Urban Mytrh will stay until the " The Day of Judgement " OK, do you want a suggestion ? If you have the GBP £ 900.00 and it does not hurt you spending them, get it with EC ... If you are not convinced then do not get it ... Rainer
  7. Hi, Pe is periodic error and it comes due to the fact that the outer circumference of the worm is slightly eccentric against the rotation center of the worm axis. So what happens then is that the worm has a different speed angular peed at the touching point of the worm gear. TThe highest point of the wormhas a high speed and the lowest point of the worm has a low speed. So the worm gear has sometimes a high speed and sometimes a low speed and that gives you a sinusoidal curve. The height of the curve is dependent of the size of the eccentricity. Now the encoders measure in real time the speed of the worm gear and correct it to the selected tracking speed. According to this the guider does not need to correct the PE but only has to correct the drift of the star be it due to Polar Alignment or atmospheric refraction. Encoders do not make obsolete gu ding but make guiding more comfortable. I am guiding sending a guide ping every 15 seconds to my mounts. Is it worth or is it not worth ? For me it was worth ... You will have to ask yourself if US $ 1.310,00 (~ GBP £ 1.000,00 + VAT in UK) is worth for you or not, but the worst thing is that you will never know if it was worth or not. You can not deactivate the encoder on a CEM 60EC. Either you have encoder or you do not have encoder built into the mount. So no way to find out afterwards. If you have the US $ 1,310.00 get it ... I have two CEM 120EC2 and the encoders where worth every cent (Europe and Mexico) or penny (USA) ... Attached two graphs for a guide session over 2h 30m. One is the RMS and the other one is the GuideError As always just my opinion. Others may have other experiences. Rainer
  8. Hi, Right but there has to be difference at those prices ... ? DDM85 and EQ6-R and CEM 60 ? Did not find the DDM85 but found the DDM100 and read they use encolders for " ... excellent tracking ..." ?
  9. Hi, Interesting how stubborn the Urban Myth of encoder and unguided imaging stays in this Hobby. Be it an absolute or an incremental encoder the only purpose of this is to kill the Periodic Error = PE nothing more nothing less. The pointing accuracy of course get better as you something onto which you can measure your movement e.g. distance traveled. I personally do not see an advantage of an absolute encoder in our hobby. I was working for more then 15 years with two Losmandy G11 mounts and the only encoder where those for the servo motors in order to keep the correct speed and a possible positioning but what can you expect from a little dicd with lineprinting and a diameter not bigger then 16 or 17mm ? Not much. Every time I shut them down or the power was interrupted they knew exactly where they were. Of course opening the clutch and moving by hand was prohibited. You lost then everything and needed to make a manual homing. Nowadays not necessary as they have homing sensors. Now the big marketing hype for using absolute encoders is " your mount will always know where it is ",. OK the incremental also know it. Question: Just because you have absolute encoders you will be playing around all night opening the clutches, moving the axes and tighten the clutches and then go to the object and so on and so on ? Just for fun and so justify the price difference you paid for it ? If yes, then ok get a mount with absolute encoders. Not even Planewave on their mounts have absolute encoders. They also use a separate sensor for homing. Now coming back to unguided imaging hype with absolute encoders. OK, you have set up your mount and Polar Aligned as good as you can. Now you tell the mount with absolute encoders to go to RA XXh XXm XX.Xm and DEC XX° XXm XX.Xs and the mount with the absolute encoders goes to that position (absolute encoders are coded for that and have coding for each position as fine as possible and the rest is interpolated by algorithms and now you take an image and wonder why is my object NOT in the center. Very easy and because of your not perfect Polar alignment. That easy are fooled the absolute encoders. So now you center the object and you take an image now and it is centered and then you take an image in an hour and again it is not centered, you think WTH is goin on, I ahve absolute encoders and the mount should stay put oin the object, nice thinking but again you Polar alignment summed up with atmospheric refraction has moved the object to a new position but your absolute encoders are sitting exactly on your coordinates A XXh XXm XX.Xm and DEC XX° XXm XX.Xs as they were told, but no, the object moved due to PA and AR ... and so you will always need a feed back and that feedback can only come from a camera imaging the part of the sky and at start you marked the position of the object with X axis XYZ pixels and Y axis XYZ pixels and now when the object changes the pixels position you read it and command back the mount so the object is in X = XYZpixels and Y=XYZ pixels. Think of your car with electronic steering aid. From time to time you need to correct your track on the M5 ... ? What is the advantage of encoders. You just have to keep on the right track your mount and that can happen every 10, 20 or 30 seconds (I am doing it like that as I have two CEM 120EC2) and have learned to thing now outside the box and send one guide PING every XX seconds instead of inside the box every 2 or 3 max 4 seconds depending of the worm period and PE. The encoders take care of PE and not having encoders the guiding has to take care of PE and right track. For correcting PE you do not need absolute encoders. Absolute encoders do also have a track for purely incremental measuring. Think about it Rainer
  10. Hi, This is wrong what you are thinking. The need for adding extra weights laterally does not come from the mount . It comes from asymmetric weight distribution of the telescopes or the equipment you put on top if the saddle plate. For example a reflector with a attached finder scope will always be heavy to one side if you do not put the finder scope exactly on top of the scope, but then you will not be able to look through the finder scope ? That is the reason why people add extra weights in different positions. regards Rainer
  11. Hi, It must have taken hours for the Polar alignment ? Great shot ! Rainer
  12. I think they have somehow to set some figures. If you are really interested why not talk to them in order to get more info ? Perhaps a dealer who wants to bring one over and test it ? One thing is the writing and the other is the real world use ...
  13. Hi, The mount you see there has no encoders as it has black knobs. Encoder equipped CEM mounts all have read knobs for the worm engaging. More news to come after tomorrow Friday Do not despair, You will soon get enough info ? Rainer
  14. Take a look at the message above ☝️
  15. Hi, I guess you wanted to say " ... the design is like a bigger CEM25 ... " as here the bearings are between DEC and counterweight shaft. It is the " Z " design. CEM 60 and CEM 120 have the DEC head between the bearings Rainer
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