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fwm891 last won the day on October 27 2019

fwm891 had the most liked content!


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    http://milsomguitars.weebly.com/ https://www.astrobin.com/users/fwm891/

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  • Gender
  • Interests
    Astro Imaging, Acoustic Guitar building, Making own equipment, tinkering...
  • Location
    Kingstone, Hereford

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  1. Great stuff - I'm just a tiny bit jealous....................
  2. I've now changed my fd as I found the Baader awkward.
  3. The mirror box has had it's first coat of matt black after routing the corners to take the ali angle acting as a corner reinforcement and the anchor points for the truss poles. The top edge of the mirror box is left as bare wood at present - this will have a hardwood edging added later. The interior will have a further coart of matt black the exterior will have a clear varnish/lacquer top coat to enable easier cleaning after handling. Photos show an exterior corner and detail of the pole ends. The pole ends will be secured with a knurled circlular ali nut (temp cap head screws used at this stage).
  4. Last time I bought a grinding wheel for my bench grinder it came with a few different plastic spacers to fit the wheel to different shaft sizes. Failing that measure your shaft size and get a wheel to match it.
  5. CEM 70 G ? Try the iOptron web site and if it's like the other CEM mounts there will be a Commander version for the mount. iOptron.com support
  6. More metalwork today. Continued and put together the mirror support frame and 18 point supports.
  7. The mirrors have just arrived and they look beautiful. All packed away again now while I get myself in gear to complete the rest of the scope.
  8. fwm891

    Francis-Astro images

    Images taken using a mix of mono DSLR, OSC DSLR, Cooled OSC cameras on observatory mounted telescopes
  9. Working on the 18 point primary mirror support structure. These are the 3 pivot bars and brass domed triangle supports. Waiting on the correct cap head screws which will pass down through the triangles, through the domed pivots and into the support bar.
  10. I'm having a one person debate at the mo and can't seem to come to any reason for / against in either direction. I'm currently building a 16inch f5 dob and wondering whether I need a finder scope. I will have a x1 rdf and my though is/has/was to use a 40mm eyepiece as a 'finder' before switching to a higher mag. I've been trying most eyepiece makes/varieties in simulations to get a 'feel' for what fov such an eyepiece would yeald. A lot comes down to eyepiece design really wide fields come at a huge price and are not being considered. I like the ES 68° 40mm apart from it's weight, the pentax XW 40mm also seems a good option... But would a finder scope be a better option especially for hopping to targets... Any thoughts please especially from the larger scope brigade out there - what is/was your solution to getting to your chosen target. Cheers
  11. Started making up the secondary mirror tilt/collimation assembly. The lower plate in the photos (with the 4 cap head screws) is fixed the upper plate is allowed to tilt/tip it's movement resisted by 3 compression springs and activated via 3 screws. The actual adjustment screws will be 'tool free' the cap heads shown are temporary to let me check the movement. As a guestimate at the moment there appears to be circa ± 7-8 degrees of tip/tilt movement, more than enough to collimate the secondary. The angled plate still needs some shaping and a few holes drilled/taped to take the secondary elliptical back plate. Any resemblance to a cuttle fish is purely by chance....
  12. Started out last night doing a guiding assist check in PHD2 before trying a few subs on M27. I captured in SGP and decided to set my usual cooling on an ASi533 OSC at -12° C and just start exposing while the sensor cooled. I noticed that some of the pixels were bordered by a black ring - very worried at tis point as I'd not seen anything like this before. Decided to let the captures continue and noticed that the rings faded. They didn't completely disappear until well after the sensor was showing it was at -12° C. First 3 frames are sequential final frames some 10 mins after the others. All subs are 5 mins. Anyone seen this effect before.
  13. Thanks Huw. I use Photoshop. I draw everything full scale but drop the resolution down to 100 dpi to keep file sizes manageable. I use multiple layers to build up individual parts or bring parts togtehr to form a complete instrument. It has a feature to auto align layers to vertical/horizontal centres or top/bottom, left/right edges then link or merge them together. The version I have is old now CS3 but for this type of project it's ideal.
  14. I'm primarily an imager but once everything is running I like to sit back with a pair of bins and just look up... Making myself a dob at the moment to get more detail from areas found in the bins.
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