Rusty Strings Posted February 29, 2012 Share Posted February 29, 2012 Some of you know about a 12" newt that I've rebuilding. It was built originally in the 70's by a friend of mine and languished in his dome obsy even after he lost interest in astronomy. As a result, the elements ruined the primary coating and when he finally dismantled it to store the mirrors, he dropped the primary and took a thumbnail chunk out of the edge. I took the lot of his hands 18 months ago with a view to rebuild it. The original design which worked fine for the astrophotography of the day, didn't lend itself to being very portable so I've built the upper tube assembly and fitted ali tubing to the original hexagonal lower tube structure. It was originally on a eq fork mount, long since scrapped, so I've put it on a dob mount and even though the spider and secondary aren't yet fitted the whole thing balances very well with a sight tendancy to be heavy at the primary end so adding the spider telrad and an eyepiece should even it out nicely. Here are some pics I took tonight with it fitted to the mount for the first time. No, the primary isn't installed only a pair of counter weights that are the same weight. Link to comment Share on other sites More sharing options...
Brantuk Posted February 29, 2012 Share Posted February 29, 2012 That's looking very nice John Link to comment Share on other sites More sharing options...
Guest Kheldar Posted February 29, 2012 Share Posted February 29, 2012 That's looking really good John Will the final product be enclosed, or open as is at present? Also what cell design are you using, some scopes like this tend to have an almost "unheld" primary? Link to comment Share on other sites More sharing options...
catman161 Posted February 29, 2012 Share Posted February 29, 2012 That looks fantastic John. Will you be making the primary yourself or using a mirror kit? Link to comment Share on other sites More sharing options...
Rusty Strings Posted February 29, 2012 Author Share Posted February 29, 2012 Thanks guys. I will be fitting some baffling around the primary and secondary and I should think I'll need a light shroud I'll see when it gets first light. Felix I have a primary mirror, it was ground by my mate and has some damage to the edge which shouldn't affect the performance. The coating was hopeless so a visit to Orion optics sorted that out, it now has a lush hilux coat. Link to comment Share on other sites More sharing options...
Doc Posted February 29, 2012 Share Posted February 29, 2012 Very impressed John it doesn't look nothing like the original, what's the focal length and ratio? Link to comment Share on other sites More sharing options...
Rusty Strings Posted February 29, 2012 Author Share Posted February 29, 2012 Cheers Mick. It's F5 so I'm guessing the focal length is 60". The truss poles are not cut to length yet so I can determine the optimum length at first light. Link to comment Share on other sites More sharing options...
Doc Posted March 1, 2012 Share Posted March 1, 2012 Same way that I would do it, at least this way you can nail the focus before cutting. Link to comment Share on other sites More sharing options...
catman161 Posted March 1, 2012 Share Posted March 1, 2012 Looks fantastic John. I always wished I was good with working with wood/metal just never really tried as I don't have a clue about it if I'm honest!! Link to comment Share on other sites More sharing options...
Rusty Strings Posted March 1, 2012 Author Share Posted March 1, 2012 I do have acces to a well equipped workshop which helps no end. The next stage will be the spider. The original one was on a single 3/8" diameter steel stalk that I was never keen on. The chap that built it used the scope for DSO imaging so I'm guessing the two bright defraction spikes didn't bother him. I intend to use it for more general purpose stuff so planetary/lunar stuff might not look so hot. Link to comment Share on other sites More sharing options...
catman161 Posted March 1, 2012 Share Posted March 1, 2012 Sounds interesting-would love to see it sometime when ya finished. Is it intended to be portable? It's pretty huge! I have mild back ache lugging the base of my comparatively tiny 200p any significant distance! Link to comment Share on other sites More sharing options...
Guest black eyed hexy Posted March 1, 2012 Share Posted March 1, 2012 Very interesting John , enjoyed the pics , I,m considering using hilux coating,s on my bino mirrors, I,know that it is twice as much as standard coating,s , but can,t make my mind up who,s opinion to go with , so would appreciate your view if you have an opinion. thanks dan Link to comment Share on other sites More sharing options...
Rusty Strings Posted March 1, 2012 Author Share Posted March 1, 2012 (edited) I can't comment on the performance as yet. When I took it up to Orion I asked them to test the figure and would determine whether or not I went Hilux. Apparently it is very good (I didn't make by the way) so it got Hiluxed. It cost £146 which added to the £50 I bought the scope for and the £50 or so for plywood, ali tube and fixings, £40 for ebony star laminate, it won't have cost much for (hopefully) a good performing 12"dob. Edited March 1, 2012 by Rusty Strings Link to comment Share on other sites More sharing options...
Daz Type-R Posted March 1, 2012 Share Posted March 1, 2012 Fantastic, keep us updated John, like Felix, wish I had the time and know-how to build such a thing. Link to comment Share on other sites More sharing options...
philjay Posted March 1, 2012 Share Posted March 1, 2012 Thats looking reallygood john looking forward to hearing how 1st light goes Link to comment Share on other sites More sharing options...
Rusty Strings Posted March 1, 2012 Author Share Posted March 1, 2012 Cheers mate, just need to sort out the spider. Link to comment Share on other sites More sharing options...
Guest Bryndalf Posted March 1, 2012 Share Posted March 1, 2012 As usual mate, your workmanship looks outstanding! Link to comment Share on other sites More sharing options...
Rusty Strings Posted March 1, 2012 Author Share Posted March 1, 2012 thanks Bryn Link to comment Share on other sites More sharing options...
BAZ Posted March 1, 2012 Share Posted March 1, 2012 That's a nice looking scope John, with a mirror of that quality in it, the views should be outstanding. Look forward to seeing it down the CC when you have it finished. Link to comment Share on other sites More sharing options...
Guest Bryndalf Posted March 21, 2012 Share Posted March 21, 2012 Hows it coming along John? Link to comment Share on other sites More sharing options...
Rusty Strings Posted March 21, 2012 Author Share Posted March 21, 2012 Not had much chance to do owt recently. Hopefully the summer will get the job finished Link to comment Share on other sites More sharing options...
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