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I'd like to make a binonewt telescope
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Hello, I've been in the shadows reading for some time not posting, but I figure its time to reveal myself. This will (hopefully) be my first ATM project and although its probably not the best thing to start with in terms of being easy, I hoped to make a 8" binocular telescope. I was planning on grinding the mirrors myself using the kit from william-bell , making my own tool instead of using the second blank so I could make two mirrors (I would have to order more grit I assume). Is that even possible to do? I read over Stellafane's website and many others about ATM, but they don't always give those tips that people have discovered that forums can provide. I also ordered Texereau's book and requested a few others from the library, but I haven't received any yet so I figured I'd ask on the forum while I waited. I found a site outlining a 12.5" binocular telescope and he mentioned using Dale Keller's Newt 2.5 which is a windows only application as far as I could tell, I am using a mac and I was wondering if there was any software that was similar. Any software for ATMing would be nice too. Please and thanks 
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Re: I'd like to make a binonewt telescope
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This is indeed ambitious for a first project... Maybe you should make a normal newt first to get it right?
As for grinding the two mirrors, I think it will be difficult to have the two focal lengths within the tolerance for a binonewt, especially if they are your first ones.
I see in your signature that you have a homemade dobsonian so this is not your first atm project?
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Re: I'd like to make a binonewt telescope
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Yeah I was worried about that, it probably would be best if I would save this project for latter. The 6" Dob was given to me by my uncle, it was made by his friend... who had left it in storage for many years without a cover  So there was a VERY thick layer of dust on the mirror. The coatings seemed fine though so we carefully cleaned it off. The biggest problem was it didn't have a focuser, just a drop in tube
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Re: I'd like to make a binonewt telescope
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Maybe you could make a standard newt but with a bino in mind, that is with an industrial mirror of reproductible focal length and as much reusable parts as possible (the primary cage and mirror cell come to mind) for turning it into a bino later.
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Re: I'd like to make a binonewt telescope
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Good idea, I never thought about doing that
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Re: I'd like to make a binonewt telescope
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I did find this website and he has an interesting way of making two mirrors that will end up being the same.
http://lerch.no-ip.com/atm/
"Since I’m building a Binocular telescope I need two mirrors. To make it more fun each mirror must be exactly the same! To do this I ground both mirrors on the same tool, which worked amazingly well! To implement this I would put down some grit on the tool, Put mirror A on top, do 2 laps around the barrel, with 20 cordial strokes per position, and 8 positions around the barrel to make 1 lap. After completing 2 laps I would set aside mirror A, add fresh grit to the tool, put mirror B on top and repeat."
Was it luck or will that actually work?
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Re: I'd like to make a binonewt telescope
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Hello Star Gazer...If you were to Google Derek Newton, you may find a wealth of information as I have been helping him in his quest to build a 20-24 inch bino of his own design and he displayed the unfinished scope at this years Texas Star Party...
To be finished next year...just too many thing to work out before the finish...
Best Regards,
Preston
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Re: I'd like to make a binonewt telescope
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Thanks Preston, what are some issues when constructing a binoscope? I know alignment is a major factor, but are there any others?
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Re: I'd like to make a binonewt telescope
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Okay, I got Texereau's book today... now to start reading 
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Re: I'd like to make a binonewt telescope
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Consider grinding a 6” for the telescope you have. That should be doable in about 40 hours of work. You would not need to build the rest of the scope because you already have it. Pay particular attention to control of the focal length.
I suggest that you get two identical 8” blanks. Using a plate glass tool and a Pyrex blank is asking for trouble. They will not grind at the same rate when using the same tool and same grit. They may not be the same thickness and their thermal properties will not be the same. There is much to learn by completing a 6” before making your plans for your Bino.
I was in the same position a few years ago when I wanted to build a 12.5” Newt. I first completed a Pyrex 6” F/9 and learned much about telescopes. It was a thrill the first time I focused it on the Moon. As I was viewing the ISS transited the moon. This was my first light with my 6” and that feeling can never be replaced by any other scope.
With that scope complete I completely redesigned my 12.5”. I have learned many things that I would not have known just be reading books and forums. Now I have a solid design for my 12.5”. This time I went with Fused Silica 12.5” F/4.5. I am working on the parabola at this time. I have not worked on it for several months due to a new job, a new house and issues at work but I am building the scope so that it will be available for my star test.
Good luck with your project!
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Re: I'd like to make a binonewt telescope
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Wouldn't I need to keep the focal length the same as the current scope as to not effect the focus and doesn't the william-bell kit also use two pyrex blanks (or maybe I misunderstood what you were saying, I'm new to this and its a very good possibility)?
Good luck on your 12.5" Scope!
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Zoomit
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(sage)
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07/04/09 09:06 AM
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Re: I'd like to make a binonewt telescope
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Quote:
Hello Star Gazer...If you were to Google Derek Newton, you may find a wealth of information as I have been helping him in his quest to build a 20-24 inch bino of his own design and he displayed the unfinished scope at this years Texas Star Party...
To be finished next year...just too many thing to work out before the finish...
Best Regards,
Preston
Googling Derek Newton (and other relevant words) didn't lead me to anything about telescopes. Do you know of any links to pictures of his telescope?
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Zoomit
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(sage)
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07/04/09 09:13 AM
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Re: I'd like to make a binonewt telescope
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Star Gazer94,
I suggest diving into the Binewt Yahoo! Group. It's the best resource anywhere to understand the particular challenges associated with making binocular reflectors.
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Zoomit
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(sage)
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07/04/09 09:24 AM
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Re: I'd like to make a binonewt telescope
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I'll also add that a binewt is not for the faint of heart. I haven't made mine yet, though I've designed dozens of configurations. I haven't found one that satisfies all my requirements. Making two similar focal length mirrors is just the beginning. I'll definitely be buying my mirrors!
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Re: I'd like to make a binonewt telescope
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Okay I joined that group, wow those yahoo groups look like a very handy place to get help on things like this, thanks!
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