Author Topic: Plans for a Portable a 6" F/8?  (Read 191 times)

Devon Dank

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Plans for a Portable a 6" F/8?
« on: December 27, 2017, 10:41:42 AM »
My ancient 6” F/8 Newtonian that I made when I was 15 years old hasn’t had any use in recent years but I’ve had a thought about turning it into something truly portable, possibly even suitable for bringing onto an airplane. Right now it’s in a square 48” long plywood tube riding the same mount described in Richard Berry’s book, “Build Your Own Telescope”. I had a thought about cutting the tube, adding hinges and clasps and folding it in half but that’s inelegant, isn't all that portable and doesn’t address the mount. Or maybe a scaled down version of one of the larger portable truss designs that are around might work as well. I figured this is the place to ask.

Anyone have any plans, pictures or links?



taccihalmo

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Re: Plans for a Portable a 6" F/8?
« Reply #1 on: December 29, 2017, 03:59:42 PM »
You could consider a "collapsing truss tube", like the one used in the Astronomers Without Borders' OneSky telescope: http://newatlas.com/...elescope/30111/

Jim Snyder

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Re: Plans for a Portable a 6" F/8?
« Reply #2 on: January 04, 2018, 06:32:37 PM »
Just a heads up from someone who's done that sort of thing. If you look at any of the ultralight portable plans, like the ones put up by Pinbout (check out his Sketchup library for a lot of good plans), they're set up for f/5 or so mirrors. What that means is that the scope ends up front heavy and to balance without adding a lot of weight you need to move the mirror box up and back relative to the bearings. It can be done, but it takes some figuring and possibly even making a second set of bearings like I just had to do for one scope

For such a small, light scope I'd think real hard about the Dobstuff design with three struts, about 1.25" in diameter. His "travel dob" designs have the poles split right above the mirror box to make it easy to break down. I have an 8" f/6 built like that and it's pretty nice for traveling, but not nearly as small and compact as the style that folds up into a small box. Depends on what your priorities are.

caheadhilldea

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Re: Plans for a Portable a 6" F/8?
« Reply #3 on: January 08, 2018, 01:48:56 PM »
I'd be thinking of a Holcombe type mount with the telescope done as a "scope on a stick" like in Sam Browne's All About Telescopes.

http://stellafane.or...es/scope17a.jpg

Holcombe Mount:

http://www.bbastrode...combeMount.html

The main strut and the two legs could go as checked luggage, probably look like an easel to the baggage guys. Cells with optics in a carry on case.

Dave

Harry Smull

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Re: Plans for a Portable a 6" F/8?
« Reply #4 on: January 14, 2018, 12:47:35 AM »
Good gosh-a-rooney, "Scope On a Stick!"

Is this a great hobby or what?

Scott Bentley

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Re: Plans for a Portable a 6" F/8?
« Reply #5 on: January 18, 2018, 03:46:42 AM »
Quote
Good gosh-a-rooney, "Scope On a Stick!"

Is this a great hobby or what?


LOL "Scope on a Stick" is actually a pretty nice looking rig

lehroldwebbdep

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Re: Plans for a Portable a 6" F/8?
« Reply #6 on: January 20, 2018, 03:02:47 PM »
you could add another "strut" on this f5 pocket scope and make the "struts" 18in longer for an f8.https://3dwarehouse....Travel-Telecope

inmactoopho

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Re: Plans for a Portable a 6" F/8?
« Reply #7 on: January 20, 2018, 04:06:57 PM »
Quote
you could add another "strut" on this f5 pocket scope and make the "struts" 18in longer for an f8.https://3dwarehouse....Travel-Telecope

Where do those rails or struts come from?

Jason Pederes

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Re: Plans for a Portable a 6" F/8?
« Reply #8 on: January 20, 2018, 07:26:50 PM »
A consideration. Do you want the scope portable as in not big and bulky...or do you want portable as in pretty lightweight as well?

If it is the first and not the second, don't be afraid to add a fair amount of lead weight to the mirror end of the scope. There is no law that says a 6 inch F8 must balance near the center of the tube. Bringing down the height of the rocker box will go a good way towards making the whole sheebang less bulky.

Just a thought

Robert Porter

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Re: Plans for a Portable a 6" F/8?
« Reply #9 on: January 21, 2018, 09:58:19 AM »
Quote
A consideration. Do you want the scope portable as in not big and bulky...or do you want portable as in pretty lightweight as well?

If it is the first and not the second, don't be afraid to add a fair amount of lead weight to the mirror end of the scope. There is no law that says a 6 inch F8 must balance near the center of the tube. Bringing down the height of the rocker box will go a good way towards making the whole sheebang less bulky.

Just a thought

The idea is to get it compact so yes, I figured that weight at the bottom to force the CG more towards the mirror end and therefore reduce the size of the mount might be necessary. I've been looking at Gary Seronik's website again. He was the original source of my 12 1/2 and his travel scopes, both versions of the 8", look appealing. I'm thinking scaling one or the other down for a 6", allowing for the different focal ratio, might be the way to go.

Chris Ingram

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Re: Plans for a Portable a 6" F/8?
« Reply #10 on: January 22, 2018, 09:13:22 PM »
Quote
Quote

you could add another "strut" on this f5 pocket scope and make the "struts" 18in longer for an f8.https://3dwarehouse....Travel-Telecope

Where do those rails or struts come from?
t slot alum, they sell all different sizes

they could slide, but me I'd just thumbscrew thru them to a plate and then unscrew rotate them around and screw them back so for travel they are 1/2 the length.

Bill Pham

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Re: Plans for a Portable a 6" F/8?
« Reply #11 on: January 25, 2018, 12:18:13 PM »
They don't make a 6"f8...

If you want to "just buy" there's a reflectors forum you can post in....this is an ATM forum

William Mendoza

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Re: Plans for a Portable a 6" F/8?
« Reply #12 on: January 25, 2018, 03:10:21 PM »
Quote
They don't make a 6"f8...

If you want to "just buy" there's a reflectors forum you can post in....this is an ATM forum


And yet his link and post gave me a grand idea for a scope build......using T-SLOT construction......which would be ATM'ing

Isidro Harrison

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Re: Plans for a Portable a 6" F/8?
« Reply #13 on: January 31, 2018, 05:50:45 AM »
But that's how it was presented. It was presented "quicker to buy"

Tyler Fonseca

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Re: Plans for a Portable a 6" F/8?
« Reply #14 on: January 31, 2018, 01:22:15 PM »
Quote
But that's how it was presented. It was presented "quicker to buy"
Wellllll isn't it? Seriously though I have been thinking about an adjustable length "transformer" style test bed setup as I move ahead with figuring my own mirrors and star testing and it gave me something to ponder.....already building an order for McMaster Carr as a result.