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Gina last won the day on May 9

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About Gina

  • Birthday 07/21/1942


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    East Devon - Blackdown Hills

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  1. Very nice Mark 👍👍
  2. This shows the new design. The axle is a 1" (25.4mm) OD aluminium tube. Another view without the rotation drive but showing the new supports. With the tube rotating, the errors caused by slack in the bearings is much reduced due to the far greater spacing. The extra holes in the turret plates allow cables from the cameras to be fed through and into the end of the axle tube, then through the tube and out the right-hand end as shown here and to the control box.
  3. I tried to implement the 60mm aluminium tube axle to allow guiding but I failed to get a good enough fit onto the tube and there was slop that would would probably make guiding useless. As a result I have embarked on a different approach abandoning the fixed guider and going for a simple guider attached to the front turret plate. I have still gone for ann aluminium tube as a conduit for the cables but a smaller one and rotating with the turret. This makes for a much more accurate setup.
  4. The imaging run showed that to use the 200mm lenses guiding is needed. Short exposures gave nice round stars but there wasn't sufficient signal in the stars to star align except with the more sensitive 294 sensor or binned. The subs taken with ASI 1600MM-C in Ha were no good.
  5. Have 200mm lenses on and hoping for a rough test run tonight. This is a "bodge-up" to have it ready for imaging. More work to do. eg. focus drives.
  6. These photos show the turret rig on the EQ8 mount in the observatory.
  7. Turret construction. Two plates make the sides of the turret. These have rebated holes to hold the camera casings and 3 spacers. This shows the version with adapter for the 10mm SS axle.
  8. This shows the selection of lenses I shall use with this imaging rig. 28mm f3.5 55mm f1.8 105mm f2.8 135mm f2.5 200mm f4
  9. This shows the remote focus worm drive. It uses the little 28BYJ-48 stepper motor with built-in gearbox. The worm gear is clamped onto the lens focus sleeve and the motor bracket onto a fixed part of the lens. A screw in a slotted hole provides adjustment of the mesh of the teeth (pic 3).
  10. I was going to use worm drive for the rotation of the turret but when it came to testing, there was a problem with tolerances with the mesh of the teeth. These are curved and the mesh has to be right in two directions. Consequently, I decided to go for a much more tolerant spur gear arrangement. With the large drive gear and a small pinion on the shaft of a NEMA17 motor there is still sufficient reduction. 18:1 ratio is readily achieved giving 20° turret rotation for one turn of the motor shaft. With 1.8° steps this gives 10 steps per degree of rotation. Here are a couple of screenshots of the gears in the slicer (Simplicity 3D). Meshing in CAD screenshot.
  11. This model shows the design of the turret plates (sides) to hold the cameras and rotate on the central axle (a 60mm OD aluminium tube).
  12. Before the aluminium tube arrived I went for this design. It uses a 10mm stainless steel rod for the axle. A drum was designed and printed to act as an adapter between the axle and the turret plates which have 60mm diameter holes. A separate gear ring was used to rotate the turret so that parts could be redesigned without printing both parts as one unit. (These 10" diameter parts take a long time to print.)
  13. Thank you Mark. WOW!! Lot of catching up needed here. Mind you, a "blow-by-blow" account is not really needed. Current state is that I have a turret made taking 3 ZWO cooled cameras and have recently added the third, an ASI 294MM-Pro. I have tested terrestrial imaging with the new camera but not the cooling as yet. New camera is running off an RPi 4B via USB3. The other ASI 1600MM-Cool cameras are using RPi 3B+ and USB2. The difference in download speed is amazing! I'm using the relatively new Astroberry Server as the RPi 4B firmware.
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