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Darren Drake
Pooh-Bah
Reged: 10/09/02
Posts: 1294
Loc: Illinois
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I have a good friend who will be working on a 16-inch mirror and is planning to build the scope himself. Because he has a 4 door compact car with a small trunk he will have to go with an ultra compact design. Are there any good blueprints for such a scope in the 16-inch f/4.5 range that he can work with? Thanks.
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Astronomy educator/Sidewalk astronomer
Owner of Astronomy Delight franchise
18 inch f4.42 Dob on eq platform w ST120 f/5 finder
12 inch Zhumell Dob modified by Brian Reed on eq platform
8 inch f/8 eq planetkiller
William Optics red 10th Anniversary 80mm FD
PST
24lb eyepiece box
Cernan Space Center astronomer
Member of Northwest Suburban Astronomers
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MitchAlsup
super member
Reged: 08/31/09
Posts: 186
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I have a 20" DOB that will actually fit in the back of a C4 Corvette. Be happy to share the relevent design with him (or anyone else.)
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Alan1956
super member
Reged: 02/07/05
Posts: 137
Loc: Albuquerque, NM, USA
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Here is my 16" scope: http://www.xmission.com/~alanne/DS4/DS4Main.html. I am also working on a 20" ultralight at http://www.xmission.com/~alanne/DS5/DS5Main.html
Alan
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reiner
super member
Reged: 09/28/05
Posts: 100
Loc: Freiburg, Germany
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Hi Darren,
I recently built a 16 Inch Dob for our local astronomy club. I did not push it to the extreme with weight and size. Still, it should fit into any car. Total weight is 30 kg, with the mirror box (with installed 14kg mirror) being the heaviest part at 20 kg.
Here are pictures and more information about the scope.
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Reiner
22" and 14" Dobs on EQ platforms
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RossSackett
professor emeritus
Reged: 08/17/07
Posts: 692
Loc: Memphis, TN
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Nice scope, Reiner. I like that mirror cell very much. Can you post details of those collimation bolts?
Ross
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"A craftsman relies on science when the state of knowledge allows it, tradition and experience when it does not, and makes art whenever he can."
12 scopes from 4.25 to 18" and a 24" in progress. 12 ATM awards. Webpage: http://stardazed.com/ Some more scope pix at http://www.flickr.com/photos/8315630@N04/
Anagrams: Amateur astronomer = A mature moon-starer; Dobsonian maker = Debonair as monk
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reiner
super member
Reged: 09/28/05
Posts: 100
Loc: Freiburg, Germany
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Hi Ross,
the mirror cell and its collimation is very simple. The upper corner of the triangular cell is fixed in the mirror box and only the lower two corners are used for collimation. The collimation bolts are rotatable relative to the cell (therefore the two nuts to lock it) and go through threaded inserts in those wooden blocks in the mirrorbox. By making the collimation bolts long enough, you can collimate the cell from above the mirror box. This is technically not clean, as the cell (and the bolts) are tilted during collimation, which might lead to blocking of the bolts in the inserts. Practically, however, this does not happen, as there is always some play.
I hope I made myself understandable 
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Reiner
22" and 14" Dobs on EQ platforms
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RossSackett
professor emeritus
Reged: 08/17/07
Posts: 692
Loc: Memphis, TN
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Thank's Reiner--perfectly understandable. You let the bolts rotate freely in the cell, captured by threaded inserts in the wooden blocks. That is exactly what I wanted to know.
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"A craftsman relies on science when the state of knowledge allows it, tradition and experience when it does not, and makes art whenever he can."
12 scopes from 4.25 to 18" and a 24" in progress. 12 ATM awards. Webpage: http://stardazed.com/ Some more scope pix at http://www.flickr.com/photos/8315630@N04/
Anagrams: Amateur astronomer = A mature moon-starer; Dobsonian maker = Debonair as monk
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dave b
Post Laureate
Reged: 05/10/05
Posts: 3548
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Quote:
Here is my 16" scope: http://www.xmission.com/~alanne/DS4/DS4Main.html. I am also working on a 20" ultralight at http://www.xmission.com/~alanne/DS5/DS5Main.html
Alan
Nice pages!
the ds4 page url does not work, it should be:
http://www.xmission.com/~alanne/DS4/DS4Main.html
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dave bonandrini
30" f/5.2 Dobsonian
President of GCAC
Astromart Moderator
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