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About Vroobel

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    Liverpool, UK

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  1. Probably you are right, as other people told me the same. They told also that cheap MIG welder is not good choice, but I don't have too much money to spend. I have to buy a good quality mitre saw (Evolution) and also high class bench drill press (Bosch). The welder is not only purchase related with welding. Years ago people didn't know MIG technology and used electrodes only and despite that they had not bad results. I think I could do it like many other, just have to be patient in learning.
  2. I wrote "no so high accuracy", that means 1 arc sec / step or 0.5. It's not too bad I hope.
  3. BTW, I bought an arc welder last week together with everything necessary to weld. I have 2 weeks till end of the June to learn welding enough to perform solid and good looking joints. Later it will be difficult as I come back to work.
  4. Thank you. You are right, I gonna use the small worm gear to drive the HD. Taking into account ratios of the HD and used worm gear, 200-400 stepper motor and its micro steps (LV8729) I can reach even 0.1 arc sec/step accuracy for the Ra axis. The Dec axis will have not so high accuracy, but sufficient enough. I want to use my earlier experience and make worm gear again, but this time I will use smaller fully aluminium blank. I have some sketches but excluding the fork I'm not sure if anything of my concept can be understood. It will be much easier to see that built step by step.
  5. Hi, Usually I make my astro-toys, then make a video and show them on YouTube and astronomy forums. This time I will struggle with a subject whitch I am not familiar with, thus I have to ask You for help. Especially someone living not to far from Liverpool or Manchester. I gonna make a bigger EQ fork mount for my 10" Bresser Messier (ES) reflector. I wouldn't even try to think about that without some very important and remarkably expensive part which I have bought as it is no longer able to be used at original environment. I mean a harmonic gear. My one is a little bit broken in area
  6. Hi, I have the Sony Nex-6 camera, that doesn't support wired intervalometers, so I had to do something to solve a problem of longer exposures. Please watch my another video presenting my own IR intervalometer based on the Arduino.
  7. Hi, As I used a theory described in article of The Royal Astronomical Society of Canada as a base for my derotator acting, I decided to inform them about my project. An effect of the correspondence exceeded my vision: the author placed an information about my derotator in the article. http://calgary.rasc.ca/field_rotation.htm
  8. Thank you for the information. Inside my derotator is simple universal board with only LV8729 driver and set of jumpers for micro steps set up. I can think about it and add a feature of the rotator when I make step towards the ASCOM compatibility.
  9. That is right. But that doesn't change the problem of positioning the rotator before every session. This feature requires the ASCOM as well. Moreover, I know that some indicator of "zero" position should be implemented there.
  10. I cannot say that I didn't think about it. But how will you connect it to your exact stuff? The derotator needs 12V, that is easy. Beside that it gets Direction and Step signals from the Raspberry Pi. And GND of course. I made it this way to adapt it to ASCOM in future, but the future isn't now yet. I don't have mount compatible with ASCOM, so cannot test it anyway. Edit: The LV8729 stepper motor driver can work with 6-36V, so the 12V is there only because i operate with this voltage in my system.
  11. Look, the derotator is a kind of proof that it is possible to make it at home. It was like a bet with some people from the community. Since I finished this quite nice project I gonna prepare to performing of a big fork mount able to drive my 10" OTA. Today I made a deal and I nearly have strong harmonic gear box. That should be strong like the EQ8. I don't expect any problem with astro-photography at all, maybe only the light pollution...
  12. I wrote my system completely on my own. I calculate both Az and Alt and put them into equation shown in video. My Latitude is taken from GPS. Everything else is a calculation based on complicated algorithm developed on my own as well. Finally every picture presents objects with the same angle.
  13. As you could see in my video I have Dobsonian mount so I cannot perform longer exposures than 25 seconds. Every longer one captures star trails. Presently, with the derotator, I am able to leave my camera set up for thousand pictures and go home to watch TV or movie. The only problem is that my drives have strange small movements invisible without capturing the pictures. Short exposures like 5 or 10 seconds show nothing, stars are simply points. But longer ones make patterns like butterfly., so I think the error is looped. I ordered better quality stepper motor drives and want to replace them
  14. Hi, I'd like to show my setup in the last action. Regards, Tomasz
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