Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_comet_46p_winners.thumb.jpg.b3d48fd93cbd17bff31f578b27cc6f0d.jpg

Rainer

New Members
  • Content Count

    42
  • Joined

  • Last visited

Community Reputation

55 Excellent

About Rainer

  • Rank
    Nebula

Profile Information

  • Gender
    Male
  • Location
    Mexico
  1. 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
  2. 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
  3. Hi, It must have taken hours for the Polar alignment Great shot ! Rainer
  4. Hi, I have had a normal GEM and now have CEM mounts. In a real world use both had or have the limit when imaging with the telescope in vertical position. So IMHO no difference in use ... the camera will crash in both cases into the pier or the tripod. what ever you do. Of course if you want to limit your imaging to certain areas of the Sky the GEM has a possible advantage. Maybe 20 years ago that could have been an advantage but aking into consideration the software tools which we can have nowadays there is no difference. Rainer
  5. Hi Waldemar, Quite true ( Apples = iOptron and Pears = ASA )and there you see ... I just saved US $ 14,000.00 by buying the iOptron and in a few years I can spend those US $ 14,000.00 on two " iOptron CEM 180-DD " mounts with direct drive ... Look, Waldemar, I stepped up from two Losmandy G11 8 completely overhauled and made better by me 15 years ago) and ahving had a tiny iOptron ZEQ 25GTO ( now CEM 25) I knew the build quality and yes I took the risk of being an early adopter of the EC2 technology. My mounts do ahce serian number GB 20001 and GB 20002. Yes the very first two beats of the EC2 line. OK, there have been glitches which is very normal and every mount producers has had but I have time and I enjoy beta testing sometimes more then perhaps doing Pretty Images This beta testing makes me understand much better what I have then just unpacking a Plug & Play toy ... Just day dreaming but quite possible as the Chinese guys are innovative and risky compared to some other " Premium Mount " manufacturers. Look at the Korean ? Rainbow mount ? The future is going to be interesting ... and if the development pace keeps going like this we will sooner then later see some interesting stuff coming from the other side of the pond (for me in this case the Pacific Ocean) Have a nice day or what is left of it Rainer
  6. Me too 600 seconds not guided at 3200 mm focal length with an iOptron CEM 120EC2 The object is the Arp 3 and this is a single shot. Stacking many shots I guess makes the image even better
  7. Hi Waldemar, I appreciate your effort to convince me that my iOptron do not work good. No Problem Just kidding BTW, OK, I can read the forum but if the images are not in the forum I can not see them when I am not a member. Also the images I have seen and the telescope used just says 10" ASA but no focal length and so it is relative. I tried to find out the f ratio of a 10" ASA telescope but the poage of ASA does not list them anymore. The smallest one now is 400mm or ~15" ... Again I am walking in the dark about the capabilities of the mounts. Believe me I do not want to read I want to see. Writing = Reading is subjective. Images are more or less Objective ... I do not want to start a discussion here about what is better and so on. I have read many many postings os many many different mounts and most of the people just have had one or two brands and of course that one are then always the best. There is too much bias in writing about a product ... It will be never objective ... I am happy with my iOptron and do not see why I should spent 3 or 4 times for a mount when the difference in the result = image is maybe 5% or less, or the difference is 5 hours PixInsight or 30 minutes Photoshop Mount here, mount there, all is nice but the main problem is our atmospheric conditions and that will not change if I have a US $ 7,000.00 mount or a US $ 21,000.00 mount ... Also the interest of the people is as different as we all are ... Waldemar Thanks again and best regards Rainer
  8. I can not create an account at the forum ...
  9. Hi, iOptron's CEM 120EC and EC2 do NOT have absolute encoders. They have incremental encoders and a homing system which is quite reliable to set it into the zero position and from there start again. A power outage does not matter as the last position is always remembered. In regards to unguided imaging I dare to say that it is wishful thinking. OK, with encoders, be it absolute or incremental the mounts point always to the coordinates you made the GoTo, but, does the object remain there or does it wander due to refraction, thermal currents, not perfect Polar Alignment (which from my point of view is impossible to achieve) etc. So guiding is IMHO necessary but with encoders guiding becomes easier. I have two CEM 120EC2 mounts and a lot of hours with them under dark sky and I dare to say Unguided imaging over 2 or 30 minutes are wishful thoughts. Too many variables in that time lapse. 300 and at utmost 600 second images unguided are possible but not at 2400 mm focal length. I image with 999 mm and 3200 mm on my CEM 120 EC2. regards Rainer as always just IMHO and YMMV PS Are two encoders worth it ? Yes and for the price of the CEM 120 EC2 even more. In 5 - 7 years when there is a new iOptron CEM 120XXX or even a CEM 240XXX the money you did not spent today will be a good reserve to get the newest one in the future ...
  10. 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 ...
  11. 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
  12. Take a look at the message above
  13. 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
  14. Hi Sunshine Thanks I use Lucam Recorder which is an acquisition software developed by a German many years ago but unfortunately he stopped working on it as he had bigger ideas which I think did not materialize so far. This software is capable while saving the videos in real time to apply a false colour mask. This means it has a feature where I can adjust the RGB curves in such a way that the black background is turned into that light grey and so I get all these details in one single shot. The software works only on Lumenera cameras from Canada and the infamous Astronomycameras also named TIS. regards Rainer
  15. Hi, Again Sunshine not full but took advantage of a spot with no High clouds.
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.