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Chriske

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About Chriske

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    Proto Star

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    BE
  1. Correction : my mounts closes as I explained higher up. The hinge is at the east side of the mount, the threaded rod at the west side. So I need to close the box to track the stars.
  2. Although I made a smaller boxmount with which I've taken pictures of the nightsky, I never used my larger Boxmounts to do astrophotography. I think it would be feasable using a precise threaded rod. For the smaller one I used a threaded rod I did cut it myself on a lathe. for my large Boxmounts I simply buy threaded rods. That's because I never take pictures with that large one. The thick threaded rods are 'rolled', not cut. These rolled rods do not allow smooth tracking, far to many irregularities in the threads itself. But perfect to track stars for visual observing. Tracking stars with these threaded rods there's a 'wobble' in the motion, but only a veeeeeery small wobble, most of the time hardly visible. What could be done to improve tracking precision is cleaning up the surface of the rolled threaded rod with a die. It makes a big difference. Precise tracking to do astrophtography is only possible when the upper part of the platform is near the horizontal position and for a short time. Remember it is in fact nothing more then a barndoor tracker, only 'a bit' larger. The hinge I use is a heavy duty one. To compensate for the weight of the scope + upper part of the platform I always use a pneumatic lift unit. It's nothing more then a pump out of a rear-door of a car(not mine..,-)). You need to test were it has to be installed. You can fine tune this system until the scope 'only weigh just a few grams'. To compensate for different temp outside I place a very small weight on top of the platform. When it gets colder I relocate that (very small)weight more to the west of the platform. Works perfect. That adjustment is only needed to compensate for Summer/winter. The largest Boxmount I ever made is 1m² and is patiently waiting to carry a large binocular I'm busy building(2x20") is on hold now, due to build of 150mm (lens)bino. To fully understand how it works, you need to look at the pictures of my Kutter-Bino. And btw Nigel, the rotation axis of a boxmount is not at the centre of the mount. That axis is mounted at the far-west or the far-east side of the mount. Tracking with that rod is done at the opposite side of the hinge. See here. I prefer to mount the hinge at the east side and the threaded rod at the west, so the telescope is 'falling down' during tracking. You can reverse the two, so you would be pushing the telescope upward. But I prefer the first one. Don't know why but it 'feels' more natural imo. In the pictures of the Kutter-Bino I made the paltform round. That's the only one. All other are square platforms, because it far easier to attach the driving parts.
  3. These are a few leftover from a very old apple tree. It had to go, pity.
  4. Why not use a star diagonal Rusted, so no need to a Limbo...
  5. But I think it"s time to leave this thread. Although it is a eq. platform, it has nothing to do with the original post. Sorry Neil...
  6. This is my latest 'boxmount' it differs a lot compared to my original design. It action is very smooth btw. Needles to say, the tripod is very sturdy..:-)) For those who are not familiar with the boxmount ; lots of drawings and pictures on this page. There are lots of (white)printed parts involved btw
  7. The idea btw is not mine. I read about it in 'Astronomy' magazine(late '70, if I'm not mistaken). Prof Greame White(Univ. Australia) suggested that a mount like that 'Boxmount' could solve many problems. He actually never built one himself. In that article were he wrote about his idea, he added a drawing. Noting more then a few lines, not even a real drawing in fact. I immediately started building 'my' version of 'his' Boxmount and wrote a letter + a few pictures of that built and sent it to Mr White. The man had asked in that same article to sent him the result and possibly pictures of his idea, 'to see whether his idea could be build and would do the job' if someone should build that mount. The man was very pleased with my letter and told me to send that same message to Sky&Telescope. After that first built lots of amateurs did copy that build and even improved it. Some amateurs did built a 'nested' boxmount. Anyway, I still use boxmounts for larger telescopes. The Boxmounts I build nowadays are about 15 to 20 cm high, depending on the version. And yes I always install a pneumatic lift arm assist system to compensate for the weight of the dob it'll support. Leave as is Alex, no need to edit that post. So in the end, credit should go to Mr White also. He's the one with that 'silly' idea to mount a telescope on top of a wooden box with a hinge, to track the stars...
  8. Do you have pictures of these bino's..?
  9. Yet again as always, I plan to add a IPD unit starting from 55 to 70mm
  10. Nice...!!! Thanks Peter...!...
  11. I could do that John , but there's an additional problem. A need in fact two of these lenses. And on top of that they need to have exactly the same focal length. Now you surely know what I'm planning to do with these lenses...
  12. Thanks John, but I don't think these people are selling in my budget range...
  13. All these links, they’re all mine. But absolutely out of date.
  14. Hi, Does anyone know a good source to buy a 150mm achromat, airspaced. I already found this one, is not to expensive. Thanks
  15. To be clear : The name of that file has been changed. The drawing is mine. The mount as is, is my idea. I made a couple of these mount, I call these mounts Boxmount. Published an article in Sky&Telescope in 1983(if I remember well). A variant of that mount I did use again to mount my Bino-Kutter I made last year(posted here on SGL). Posted that boxmount on CN years ago. And yes it would be most polite to mention the source/original poster where ever it has been posted before.
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