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Michele Scotti

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About Michele Scotti

  • Rank
    Star Forming

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  • Interests
    Telescope making - Instagram #800mm_telescope
  • Location
    Woking, Surrey

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  1. That's Planewave direct drive specification - 10 ticks/arcsec. Maybe it works with less but they kind of set the standard in case the DD is coupled directly to the axis.
  2. Hi John, you're right the stroke is dead center and the tool I think sub-radius - like 45% of the diameter. We tried a full tool but the friction was way too high. The main grinding was done with a CNC diamond tool. I'm definitely not an expert in making mirrors - I've only done few , long time ago. For sure I'll ask about your consideration and come back to you. Btw I've cobble up another video - not advisable if you're seasick ;D https://www.youtube.com/watch?v=w4HIsp1-zXw
  3. Work continues with #800grit: Aiming at #1000 then #1500 to prepare a pitch lap and check if we have something that resambles a sphere.
  4. I saw this several times and it is saved in my favorite yt folder. Did you try to use any water or was it messy? This is another good example: https://www.youtube.com/watch?v=eRdr86gXBLI Although it started like this....: https://www.youtube.com/watch?v=lonAulU-kWA
  5. An update on the mirror side of the project as a part of the club has been working on the mirror for a few months now. The bulk of the material has been ground off at a machine shop that works on granite. Subsequently, the hogging was done with a half tool to smooth everything out with #80 grit. You "may" notice that the route we took is the ....most impervious...but cheaper and readily available. Also not very recommendable which is a flat 25mm float glass. All in all, I'd consider this a practice run for the part of the team who works on the mirror - we'll gain some experie
  6. Well done - much of satisfaction when things turn for the best. Would you be able to make another video just like those before to check what it's fixed and what are the residual contributions. Btw is now the motor/worm assembly fixed solidly and not sprung anymore, right?
  7. The SiTech controller accepts 5v pulses as 'telescope encoder' so that gives an easy way to directly wire industrial encoders to it. In the last few months I managed to salvage parts of a Renishaw encoding system - now 'obsolete'. I suppose they are coming from some CNC machinery. Here I'm testing one of the 3 read-heads which has a 1micron resolution although the final system needs 0.1micron resolution. This equals ca. 30 pulses each arcsecond - hopefully it should be plenty for tracking accuracy. This is a very crude test just to see if the salvaged hardware i
  8. Hi Rusted, sorry I missed some of the last messages. Did you identify the source of the substantial wheel movement as per your vid here: https://youtu.be/bWKQBCOkrNw?t=14 ? Also, I recall you ordered angular bearings - were you able to instal them? Did you notice any improvement?
  9. Hi Huw, can you explain this sketch? Apologies if it's explained somehre else but couldn't find anything.
  10. If the camera is on a tripod on the floor what I see is that the wheel is moving away from the wormgear assembly. I almost have the fealing that the entire RA shaft is pushed around by the reaction on the teeth. On the video from the right side you clearly see that the housing and the mounitng plate experience small deflection. From the 'front view' video instead the deflection of the wormgear assy is more pronounced. I'm a bit baffled - would you agree with the observation? For peace of mind I'd take a vid from the left side too and another one where you can check whether the m
  11. Preparation work for grinding the Altitude rails and achieving correct precision. Stacking up the 2 pacmen and fastening them together. I'm using two steel beams to overhang the pacmen so that the swiveling 'apparatus' can go around the circumference with ease. To start with the run-out (departure from ideal circumference) is checked using a digital gauge that can sense microns. The dial starts from 0.000 at one end of the pacmen and climbs up to almost 2mm. However that seems to be attributed to the hinge point being off-center by interpreting the plotted
  12. Very useful vids - I see 3 things: 1) the wormgear sliding into the bearings - is that what is fixed by the missing washer? 2) the hosing movement - you describe it as flexure but it's not clear from the vid. Another video from the side would clear that. Again I'm a bit skeptical that a 5mm square tube will move much. It's maybe more likely that it's sliding/tilting due to the screw that allows the springed housing? 3) the big plate the housing is mounted on is seen deflecting small movenet but it's there. It'd be surprise that such plate is flexing - if it's the RA shaft housi
  13. Can you explain what do you mean with that? Can you see where the flexure is stemming from? A close-up video would be a great aid although by looking at your set-up it could be the fixings clearance for adjusting the wormgear housing. I wouldn't rule out the bearings though The big plate looks like 10mm, the square tubing 5mm, the worm housing is possibly 8mm thick. That is enough material to make a robust system. Should be somewhere else
  14. I agree although the clutch plays a role - I suggest to detach the wormgear assy and attach a camera and mark the wheel. You can then focus on freed axis and make it safely rotate around the pier - then you can take notes of the measurements conviniently fom the video. Something like this set-up: https://youtu.be/OGJyjb-h-G8 Btw I recall you started a topic to explain the build - can you attach the link pls?
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