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  1. #51
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    Wow, did you take that?
    Meade 16" LightBridge; Celestron G-8N Bird-Jones/motorized EQ5; Orion 127 Mak/go-to EQ5; Burgess 127f8 refractor; Sky-Watcher 5" F/5 collapsible dob; 90mm Mak/motorized EQ2; Royal Astro 76/910-GEM; Meade 60x700 refractor/alt/az; Zhumell 25x100 Coin Ops; GalilleoScope. Celestron 8mm-24mm zoom; lots of fixed EPs,some good, some..not so much. A small collection of surveying instruments; a forest of tripods; Canon Rebel Xti. Confirmed gadget junkie; Custodian of the Magnetic North Pole (Send $1.00 to Pierre each time you use a compass.)
    49-41-37.03N 123-09-29.61W Calculated magnetic declination: 17° 39' East

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    We have been broadcasting our presence to the Universe for 100 years now. If there is a detachment of Galactic Pest Control within 100 light years, they are already on the way.

  2. #52
    plateglass's Avatar
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    Yes the camera was a MD80 found on ebay and i mounted it to the front of my 2004 kawasaki zx6r

  3. #53
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    Just a quick update as life flys by at a million miles an hour ...im done with 320 grit now going to move on to 500 alox in the next day or so, its hard finding the time at the moment with the tour de france and work etc !!, got to put a light and a door on the shed in the next few days too and hopefully i can get some grinding done

  4. #54
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    Hi fokes im still alive !! Down to polishing now did 25,12 and 5 micron in what seemed about 4 hours total !! so anyway i was doing a bit of reading about polishing pads do i went to the cheap shop and brought some felt, the stuff used under table and chair legs and stuck it to my segmented glass tool and started polishing...after 45 minutes the drive belt broke but seems like the center was polished already so im guessing 2 hours max and the whole mirror will be done. i gave it a quick test on the moon and looks ok so far ill know more once ive done a few more hours tomorrow.. im thinking since this is going to be a planetry scope F7 maybe i can get away without using pitch but we will see.

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  6. #55
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    Well here is a quick video showing the mirror surface after 3 hours with cheap felt pads, looks like there are a few pronounced rings but hopefully pitch will clear it up, there's also a big hole in the center but not worried about that ill black it out as the secondary will cover it from the incoming light anyway.
    [ame="http://www.youtube.com/watch?v=RhJdB1KyJK4"]YouTube- Broadcast Yourself.[/ame]

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  8. #56
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    Well i decided not to carry on polishing after 3 hours with felt pads the mirror was 80% polished as you can see in the video above the mirror had some ring holes...
    Next step was to go back to 5 micron and as you can see by the photos the rings where quite deep..the first photo was after a few minutes by hand with 5 micron, the second photo was after 5 minutes on the machine.

    Ive been polishing for about 1 hour by hand with the mirror rotating on the turntable and after testing it again i am happy with the results so far it seems to be the method i use for grinding works well but once the felt pads are used this method seems not good so ive changed the machine setup to have a secondary stroke controlled by hand.
    Attached Images Attached Images

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  10. #57
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    Hi all, sorry its been a while but work and entertainment come before mirror making !!, apart from that the temp has not been good for polishing so apart from a few hours i got done on the 13 inch all polishing has been put on hold until next summer !!. The good news is i can still cut and grind so now im hogging out a 9.5 inch disk and ive got a 13 inch to hog out plus another 13 inch on the disk cutting table half done so still plenty to keep me going for the winter.
    Ive got a few new ideas for hogging out with the diamond blades as with the mirror face up it seems i can only get down to 90 inches focus for some reason,not sure why at this point so im going to attach a blade to my edging machine and grind with the mirror face down and see how that works out.
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  11. #58
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    Well since the weather has played its hand this week i have got a few photos of a mirror surface ground with 320 sic, previously it was hogged out with alox 80-120 mix, (thats how it comes in the container) then ground with 220 sic and then 320 sic

    I have shown the photos edited in nero to show the embossed image so you can get a better idea of how pits from previous grades can be seen.

    Hopefully this will show people who are interested in mirror making what to look for when deciding if you should move on to the next grit size
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  13. #59
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    One of the more useful threads. A smart man with bright ideas has been working on grinding a mirror(s) for more than one year and we still don't have first light.

    The take home message for a guy like me is that I'd probably best not attempt this.

  14. #60
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    First light for me was back in 1994, it was a 14 incher made of 19mm plate glass !!

 

 
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