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About skybadger

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  • Birthday 09/02/69

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  1. ah ok. in which case they really are 1/4"x20 threads per inch Whitworth or Unified Coarse. You can get them from ebay here <>for example for set screws and here <> for cap/Allen screws. Watch out for bolts with no threads... M
  2. They should be M6 for a chinese or japanese made mount. Different thread size. Its Metric 6mm and has a pitch of 1.0mm. M
  3. Hi all Im looking for advice on the idea of improving my mount by taking off the worm/dc servo and moving to a direct drive motor with built in encoders. The reason for this is that I get quite a large periodic error on the existing worm & wheel and have some options to address this. My kit consists of a 8 or 12" scope with 6" frac twin mounted and a pair of guidescopes, cameras, sun scope etc depending on season. So I'd like to be tracking well at 2m focal length and upwards of 30Kg payload. My thoughts on options are: Buy a new mount - rather expensive, even if second hand. Maybe £3.5K for a second hand Mesu 200 ? Replace the worm and wheel on the existing AE mount. Certainly do-able. Beacon Hill do a 11" worm for about £400. Are there any recommended suppliers for large worm/wheel sets? It coudn't exceed 11" diameter. Replace the entire worm and wheel for a direct drive motor attached to the bottom end of the RA shaft. This would also require a dedicated motor controller/driver and then an ASCOM driver. I have one of these I did for the SkySensor so the ASCOM part isn't that hard. This is probably the most expensive option but still less than £3.5K . Has anyone ht any experience of buying and fitting these direct drive motors in retrofit and what were the results ? An other option to be identified. What are your thoughts - is too long and painful to fit your own DD motor to a mount that its much more worthwhile to buy or should I perservere and sppend more time looking at the worm /upgrade the worm first for relatively small beans ? Cheers Mike
  4. For only £50 I put together this mount from two Mondeo rear hubs. Mind you, I had to prise the abs sensor housings off but once done and a decent dovetail mount added , I get a very smooth and solid head that will carry a sizeable load. I intend to add clutches and belt drive next using DC motors. Really I built it as a test stand from scrap for assembling and testing scopes up to 12" but it seems to work well enough for observing use...
  5. This is an old topic now but... the motor will need to be reversed on the worm - either by replacing with one which turns the opposite drection ( in teh case of an ac syncro motor) or by moving the motor to the other end of the shaft, reversing the motor direction that way. Or replace the whole motor with a stepper/dc motor and belt system for forward and reverse control. Good luck Mike
  6. OK - how do I get a large version linked to the summary view ? M
  7. First lunar mosaic attempt here. 8 images from 12 videos of 1800 800x800 33fps on ASi120 mono through a NA140SF Vixen. Processed in AS2 for stacking, registax for wavelets and Maxim for stitching. Quite happy with this - gonna get it printed. Cheers Mike
  8. Clas Olson are doing multiple camera mounting brackets for bikes and motorcycles . Should find something you like there. M
  9. I open mine up every 4 years and put a new battery in it. Using a reconditioning battery charger also seems to make a difference. Lidl has them at 13 gbp. Alternatively put it on a solar trickle charger. My large obbo battery is maintained this way. Mike
  10. Hi James Imagine the source and eye side by side looking towards the mirror. Further imagine the ronchi screen now an inch ahead of both. The question is - what is the impact of the ronchi screen being so far forward ? Cheers mike
  11. Hi all I am putting together an oil-bath auto-collimator rig to check over my reflectors. It occurred to me to use an off-axis guider body and its pick-off prism to feed the light source in - no heath robinson pipe assembling. Then I can just use a positive eyepiece where the camera should go to examine the ronchi lines to estimate the optics quality. This raises the question - I would need to put the ronchi screen on the telescope side of the prism - say in a filter mount . Is this too far from the source ? Is the source to ronchi screen distance important ? Cheers Mike
  12. Did you ever manage to get the dew shade off the vixen ? I never managed it on mine. Mike
  13. Given the star is relatively bright, I'd try turning off focusing to average out the noise and even de-focus slightly as long as diffraction spikes don't suck the phone out of the disk. It won't affect the photometry as long as all the star is in the measurement radius. Mike
  14. That's a little optimistic I think. What is preventing the error bars getting smaller and the number of data points getting larger - exposure time ?. A great effort nevertheless What do you think contributes to the underlying variation - detector noise or sky variations? Very interested. Regs Mike
  15. I recommend the wireless esp too. the ode is easy to setup. the programming process is also trivial as long as you have a good power supply. I have one on the bench being a web server to drive some motors. there's an encoder module, a pid module , the web server, and a json module. what could go wrong ? Mike