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#326 Dick Jacobson

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Posted 04 May 2013 - 12:10 PM

Wow! I do not know how I missed this thread! :shocked: Well, better late than never. Here is my trusty Coulter 10" f/5.6 Equatorial Fork Mounted Newtonian. I named it after my mentor back in the '70s "The Gary Barabino Reflector". This is an old shot of it before I installed a custom-made clock drive on it.

Mel

Great looking mount, Mel! I'm a big fan of fork-mounted Newtonians and have built a few. How is the stability of this scope? I'm wondering if the polar axis tube is strong enough to do the job.

#327 474747

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Posted 04 May 2013 - 01:22 PM

Does the tube rotate on the fork mount? If so, can you tell us about it?

Wow! I do not know how I missed this thread! :shocked: Well, better late than never. Here is my trusty Coulter 10" f/5.6 Equatorial Fork Mounted Newtonian. I named it after my mentor back in the '70s "The Gary Barabino Reflector". This is an old shot of it before I installed a custom-made clock drive on it.

Mel



#328 schang

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Posted 05 May 2013 - 10:09 PM

Hi, Gmussman, nice DIY scope. I am a new member and looking recently for one to buy or build, likely a 14" dob. Obviously cost is an issue for me so I am interesting in a Hubble UL14 but read here that its structure needs some mods to operate smoothly. There are a lot of info to read and learn, but I am retired and time is no issue to me :-). Assuming the mirror is of decent quality, is it worthwhile to buy the mirror/diagonal, etc to build the structure? Since the mirror takes a long time and $$ to ship to US, I wonder if this is worthwhile to wait than getting a GSO instead, other than the sandwich mirror which I like. How long do you have to wait for GSO mirror? I am pretty handy and have ton of time...

Shien

#329 Dick Jacobson

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Posted 06 May 2013 - 07:35 AM

If you like building things but are not interested in grinding your own mirrors, it makes a lot of sense to purchase the optics and build the telescope around them. I did that with my 20" scope. My 14" was originally purchased as a complete scope, but I rebuilt everything and now all that's left of the original is the optics and their mounting hardware.

Regarding Hubble Optics, I have no personal experience but I have a friend who recently purchased a UL16 and was very unhappy with both the optics and mechanics. He had the mirror tested by a local expert who said it was the worst he had ever seen. He sent the mirror back and its replacement was somewhat better.

#330 gmussman

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Posted 06 May 2013 - 08:45 AM

Shien,
I agree with Dick Jackobsen's comments above. I personally found it very rewarding to build my scope around a mirror and components. In my case, I cannibalized a lightbridge 12" from craiglist for the mirror, cell, fan, and spider/diagonal. I was not happy with the lightbridge's bearings (way too easy to move, hard to keep on target) or portability (heavy, the parts don't fit together or stack unless assembled). I made my bearings oversized, used the formica/teflon combination I like, and made it tail heavy so I can use a finder and big fancy eyepieces. Not that I own any, yet ...

The GSO mirror seems to star test very well (seriously, though, I'm not sure I know what I'm doing) and the views are amazing. I am very happy with the mirror. The diagonal, on the other hand ... well, I designed for a protostar diagonal, but ran out of money in my $1000 budget.

So I've had a great experience with the GSO mirror and with building. Feel free to PM me if you want to know any more about what it was like to build.

Grant

#331 schang

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Posted 06 May 2013 - 08:47 AM

Hi, Dick:
Thanks for the response. Look like Hubble mirror is a hit or miss thing. How about GSO mirrors? I am not going to grind my own mirror for sure due to the lack of testing equipment or the materials for it. Your and others' comments on the mechanics of Hubble structure convinced me to decide to build my own structure. Heck, there will be some issues on all new equipment. So it may be worthwhile to DIY this instead of tweaking what you bought. As for the mirror, what do you think of GSO ? While I want a perfect one, reality check (my wife, that is :D) forbids me to do so. This is an expensive hobby, which I try to minimize the costs by DIY or buy used items off the Internet.
Shien

#332 schang

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Posted 06 May 2013 - 09:04 AM

Hi, Gmussman:
Thanks for the response. I will look into used or GSO new mirrors. The bearings need to have large radii with continuous surface for smooth operation, other things being equal, I think. It will take me a while to gather materials and info to start building it, including an EQ mount. Whatever I do, I certainly will ask you veterans for guidance, that is for sure.
Shien

#333 Dick Jacobson

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Posted 06 May 2013 - 03:44 PM

I have no experience with GSO mirrors. My 14" was originally in a Discovery telescope, I believe it was made by Terry Ostahowsky and I think it is excellent.

#334 dawsonian2000

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Posted 06 May 2013 - 04:21 PM

Mel that is one solid looking tripod! :shocked: Mike


Thanks, Mikey! I was thinking of mass producing them as an alternative to the TeleVue Gibraltar tripods. At a substantially reduce price, of course.

Mel

#335 dawsonian2000

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Posted 06 May 2013 - 04:26 PM

what's that under the mount? accessory cart/powercell/coffee warmer? :grin:


... it is a Stanley rolling toolbox. I have since upgrade to the Stanley FatMax rolling workshop. Great for hauling of you astronomy gear.

Mel

#336 dawsonian2000

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Posted 06 May 2013 - 04:41 PM

Wow! I do not know how I missed this thread! :shocked: Well, better late than never. Here is my trusty Coulter 10" f/5.6 Equatorial Fork Mounted Newtonian. I named it after my mentor back in the '70s "The Gary Barabino Reflector". This is an old shot of it before I installed a custom-made clock drive on it.

Mel

Great looking mount, Mel! I'm a big fan of fork-mounted Newtonians and have built a few. How is the stability of this scope? I'm wondering if the polar axis tube is strong enough to do the job.


Hi Dick,

The scope is very stable atop this fork mount. The polar axis is made from a 2" quarter inch wall section of 6061-T6 aluminum tubing. It works fantastic! Very smooth and stays where you point it. Both RA and DEC axises utilized a Teflon-to-Metal interface, which produces what we coin as "stop right there" technology. :grin: :lol: It works fantastic! Currently, it has a custom clock drive installed to spin it. The drive tracks quite well. Here is a photo.

Mel

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#337 dawsonian2000

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Posted 06 May 2013 - 04:49 PM

Does the tube rotate on the fork mount? If so, can you tell us about it?

Wow! I do not know how I missed this thread! :shocked: Well, better late than never. Here is my trusty Coulter 10" f/5.6 Equatorial Fork Mounted Newtonian. I named it after my mentor back in the '70s "The Gary Barabino Reflector". This is an old shot of it before I installed a custom-made clock drive on it.

Mel


Yes, the tube can rotate inside of the cradle. But you will have to loosing the bolts on the cradle's top section slightly in order to do so. I will be making some retro upgrades to this instrument to make "easy of use" much better. In the interim, if you like to see more details regarding the cradle you can go check it our here on my website: Cradle Construction Overview

Mel

#338 schang

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Posted 07 May 2013 - 02:50 PM

Hi, Brian:

That is a very nice 14 incher dob. I am thinking of building one using the Hubble 14" mirror, which you used. Can you comment about their mirror/diagonal/focuser quality? I have not take the plunge yet due to the long shipping time and costs. Currently there is one on ebay with Stehle ratio of 0.985. Do'nt know if this is a good one. Any comments? Also, where did you acquire all these components to build it? I do not mind to get used stuffs if available with decent quality or new ones for that matter. Though I need to watch my pocket too :D .Thanks.
Shien

#339 rogercelliott

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Posted 10 May 2013 - 06:18 PM

Nice scope! Who made the clock drive?

Cheers
Roger

#340 dawsonian2000

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Posted 10 May 2013 - 11:13 PM

Nice scope! Who made the clock drive?

Cheers
Roger


Hi Roger,

The drive was fabricated by my friend Eric Moerman in Belgium for initial use as a DEC drive on one of his telescope mount projects. Eric is also a fine equatorial fork mount designer and builder, for which is how we became acquainted. When I mentioned to him that I was going to purchase a clock drive for my fork mount, he told me he no longer was using the DEC drive and could repurpose it as a RA drive by instilling a 7-to-1 ratio gear reduction gear box at a good price. I took the chance and it paid off. The end result is pictured above. I have since housed the wiring. :smirk: :grin:


Please let me know if you need to know more...

Thanks,
Mel

#341 BarabinoSr

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Posted 11 May 2013 - 09:06 AM

My friend and brother Mel was gracious enough to allow me to view first light through his 10-inch f/5.6 reflector on July 14,2006.The family and I visited a year after the storm . When I arrived at Mel's the scope was still in pieces, and we put the instrument togather for the first light session with me . As you can see in the image it hadn't been finished yet cosmetically and it had no clock drive . We trained the scope on M13 and M22, two of the most splendid globular clusters in the spring and summer skies.I found that the most amazing aspect of this scope is that where ever the scope was pointed, it stayed there with no image wobble or flexure issues . Mel's fork design fit the scope perfectly and it is an example of fine workmanship and quality.

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#342 badback

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Posted 25 May 2013 - 08:55 PM

My friend Manny gave this 17.5" Coulter Odyssey 2 and the Optics with it were so bad that I couldn't see anything at all except a dull black area no matter where I pointed it. Manny was going to cut it up and I said whoa there Buddy. Just give it to me and I'll sort it out.
He was right as the Optics were the worse I ever saw. As usual it turned out that the primary mirror was the culprit.
Being stubborn I tried something that seemed absurd but damn if it didn't work. Check out the two photo I've loaded.
It will show you just how easy it is to improve "missing in action" Coulter Optics without the huge cost involved with re-figuring,re-coating and shipping etc!!!
It is very self-explanatory.
Enjoy
Marv

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#343 badback

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Posted 25 May 2013 - 09:26 PM

Here is a picture of the New and improved Coulter.
Marv

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#344 badback

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Posted 25 May 2013 - 09:35 PM

Like I said VERY self-explanatory. YES?
Marv

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#345 mfpalmer

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Posted 27 May 2013 - 09:52 PM

Here's my 10" f5 Dob that I completed last week. First light was Friday the 25th of May. I took most of the design from Tom Clark's 'Modern Dobsonian' book. My first project and I couldn't believe it worked! Posted Image Posted Image

Mark

#346 richard7

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Posted 28 May 2013 - 04:50 PM

Nice looking project Mark and if nobody has said so yet, welcome to C.N.

#347 mfpalmer

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Posted 28 May 2013 - 05:26 PM

Thanks Richard. I've been lurking for a while. I saw so many beautiful projects I finally gave in. It's not the prettiest or most innovative but I'm so thrilled with how well it performs.

Mark

#348 StarStuff1

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Posted 29 May 2013 - 07:11 PM

Good lookin' scope! You are and should be proud of your efforts and craftsmanship.

Are you planning on painting the inside of the mirror box flat black? Could be already done I guess.

Also, another welcome to CN!

#349 Oscar56

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Posted 29 May 2013 - 07:37 PM

I took most of the design from Tom Clark's 'Modern Dobsonian' book.


A couple of questions:

1. where can I find that book?
2. What was the final bill for your project?

Thanks

#350 starman345

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Posted 29 May 2013 - 07:54 PM

Mark, that is a beautiful telescope, looks like a pro built it.

Grant, you can order the book here






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