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Making an 8" travel scope?

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#1 FJA

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Posted 04 April 2011 - 05:56 AM

I have an old Celestron C8 f5 newtonian which doesn't get used any more, it was given to me by someone who had no use for it any more and just wanted it to go to a new home. The optics are still good, although the mirror could do with some cleaning, but I could never get the thing collimated or if I did, it wouldn't hold and it now sits in a cupboard.

I do a fair bit of travel but, instead of just the 8x42 binoculars I usually take, I'd like a travel scope. So, I was thinking that maybe I could take the optics out of the C8 tube, keep the spider and the mirror cell (I'd put in better screws for collimation, which was the problem, the current screws are tiny allen bolts which are very short) and build a foldable lightweight dobsonian-type travel scope around the optics.
I saw a fellow Brit at the Texas Star Party in 2010 with an aluminium foldable 12" travel scope that he'd built but I don't want to get into metalwork. I am thinking of making a lightweight wooden scope that can fold down as small as possible yet is light enough to carry onto a plane (or to go in the hold, with the optics as hand luggage). I have seen similar ones but I have never seen any plans for one.

I have next to no woodworking skills, having not done any woodwork since I left school in the 1980s, so I'd like to make the scope as minimalist as possible while still protecting the mirrors. I'd like to do this all myself, partly for the sense of achievement as well as keeping costs down.

Does anyone have any experience of making such a scope and some advice they could give me? :question:

Thanks

Faith

#2 Benach

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Posted 04 April 2011 - 06:10 AM

Just make a small Dobsonian. Plenty of plans on the internet. For a compact commercially available dob, google for Hofheim.

#3 FJA

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Posted 04 April 2011 - 07:56 AM

Just make a small Dobsonian. Plenty of plans on the internet. For a compact commercially available dob, google for Hofheim.


A small dobsonian-type is what I have in mind, but made as compact and lightweight as possible. I have found photos on the net but as yet no plans, not for the sort of thing I have in mind.

I don't want a commercially available dob, I would like to make my own.

#4 Benach

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Posted 04 April 2011 - 07:59 AM

Faith: idea to go to the ATT in Essen in about a month. The European equivalent of NEAF. There you can see those Hofheim telescopes. You can also see other designs and get ideas.

#5 FJA

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Posted 04 April 2011 - 08:18 AM

Faith: idea to go to the ATT in Essen in about a month. The European equivalent of NEAF. There you can see those Hofheim telescopes. You can also see other designs and get ideas.


I would only I will have just got home from a trip to Denmark and can't get to Essen.

#6 droid

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Posted 04 April 2011 - 09:03 AM

Wow, I thought for sure more than a few of us would have plans or ideas, hmmmmm.

#7 droid

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Posted 04 April 2011 - 09:24 AM

This might help

http://garyseronik.c...taxonomy/term/3

#8 RossSackett

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Posted 04 April 2011 - 09:26 AM

I don't have plans because the details depend on the exact focal length, but I have some photos of a single pole 8" f/5 travel scope on my website at
http://stardazed.com...nsilverIv2.html
It isn't as pretty as others in the series, though.

Ross

#9 AV in CMH

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Posted 04 April 2011 - 09:55 AM

Ross,

It is a thing of fine beauty and craftsmanship.

Tony

#10 Pinbout

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Posted 04 April 2011 - 11:12 AM

well some guy named bill made a knock off Sackett design on google sketch up. If you don't have sketchup it's free so...download the model and you can make your own plans from the model cause it dimensions very easily.

Ross Sackett Scope

#11 FJA

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Posted 04 April 2011 - 11:37 AM

I don't have plans because the details depend on the exact focal length, but I have some photos of a single pole 8" f/5 travel scope on my website at
http://stardazed.com...nsilverIv2.html
It isn't as pretty as others in the series, though.

Ross


I think it's very nice and the sort of thing I'm looking at doing. :)

Thanks so far, everyone.

#12 bertb

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Posted 04 April 2011 - 01:09 PM

As the contest winner of the sky and telescope match herebye some pics of the smallest 8 inch traveltelescope in the world. Ouside 26x26x12,cm, less than 6kg, 3 eyepieces, a barlow, a chesshire a shrout and 6 trusses (each 4 parts) fits inside the box.

Attached Files



#13 bertb

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Posted 04 April 2011 - 01:13 PM

Next pic, and the scope is build from a celestron f5 newton, the same as you have

Attached Files



#14 FJA

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Posted 04 April 2011 - 01:22 PM

That's a lovely scope Bert. Do you have any plans?

#15 Pinbout

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Posted 04 April 2011 - 04:04 PM

bertb
That is very nice.
how's the wood finished? from the pics it almost looks like you left the outside raw.

#16 Benach

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Posted 05 April 2011 - 01:54 AM

Hi Bert,

Nice to see you here on this forum. We know eachother irl. :) You know who I am, you consulted me a while ago about that Newtonian with relay system. Isn't this scope a mere
copy of the scope of Tom B.?

Rgrds,

Y.

#17 nytecam

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Posted 05 April 2011 - 03:13 AM

Hi Faith - Here's a couple I've posted here previously..

http://home.freeuk.c...vin/hhscope.htm = my hardhat scope
http://home.freeuk.c...avin/bigdob.htm = my 17.5" 'portable' dob --- so something in between perhaps ;) Working plastic and aluminium is IMHO like working with wood but more versatile :rainbow: Good luck.

#18 FJA

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Posted 05 April 2011 - 05:28 AM

Love the hardhat scope, Maurice, that's got to be the most unusual use for a hardhat ever! :D

#19 Vincent Becker

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Posted 05 April 2011 - 07:12 AM

As one of the finalists of the S&T contest (congratulations bertb!), here is mine, a 8" "string telescope" which was also my first ATM project (I learned a lot from it) :

Posted Image

Posted Image

Posted Image

And some plans here :

http://www.telescope...-quelques-plans

Best regards,

#20 NeoDinian

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Posted 05 April 2011 - 08:11 AM

I kinda like the 8" briefcase dob posted here at the CN articles...

http://www.cloudynig...hp?item_id=1115

To me, I would say it's smaller than the S&T winner here... Also the inspiration for the scope I'm building. :)

#21 Mirzam

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Posted 05 April 2011 - 08:27 AM

FWIW Moonlight makes split pole connectors similar to those shown in the article above (although they are delrin, not aluminum). This is not advertised on their website.

JimC

#22 Pinbout

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Posted 05 April 2011 - 10:48 AM

Ah ha! I knew I would find it. this is the scope that I first saw... Zelfbouw: 254mm f/4,5 kofferdobson

#23 arpruss

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Posted 05 April 2011 - 11:46 AM

Here's one that is several orders of magnitude less pretty, but also perhaps easier to make than the pretty ones. More details here. Posted Image

#24 Pinbout

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Posted 05 April 2011 - 12:24 PM

several orders of magnitude less pretty



all that beautiful quarter sawn oak with flake...with the black paint splattered on it...ashamed :tonofbricks:

#25 RossSackett

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Posted 05 April 2011 - 12:47 PM

Danny,

I love the way you used the dihedral angle in the corner of the mirror box to make the rail joint for the single pole. I sketched something like that early in my Moonsilver series, but I never tried it. Congrats on making it work.

What am I looking at on the side of the altitude bearing? Is that a handle? Spring counterweight? Tension control?

Ross






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