kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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This is a 20 inch ED JONES CHief .
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veebs2
special label
Reged: 03/13/07
Posts: 287
Loc: DeKalb, IL
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Great looking scope!!
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Paul
Zhumell 10" (My Mistress - name given by my wife)
Hyperions - 5mm, 13mm and 24mm
Stratus - 8mm and 17mm
Howie Glatter 2"-1 1/4" Holograpic w/ Barlow
Lumicon OIII Filter
Telrad
DeKalb, IL
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jayscheuerle
Post Laureate
Reged: 01/16/06
Posts: 4071
Loc: S. Philadelphia, PA
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whoa...
How tall/long is that puppy?
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Fight indignorance!
The Green Goblin - 12" of dobsonian excellence!
The PortaBowl-a $100 4.5" f/8 ball-scope YOU can build!
Eero2-a 6" f/5 ball-scope you probably can't. 
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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the ladder is 10 ft/ eyepiece 7 ft above the primary // that is shorter[ eyepiece height ] than my 20 f 5 newtonian GO CHIEF GO UNOBSTRUCTED /SPIDERLESS / kevin frederick
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jayscheuerle
Post Laureate
Reged: 01/16/06
Posts: 4071
Loc: S. Philadelphia, PA
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First light yet? The Chief is very intriguing. Ed's work in general is remarkably clean. - j
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Fight indignorance!
The Green Goblin - 12" of dobsonian excellence!
The PortaBowl-a $100 4.5" f/8 ball-scope YOU can build!
Eero2-a 6" f/5 ball-scope you probably can't.
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timo4352
super member
Reged: 04/16/07
Posts: 160
Loc: Northeast Ohio
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You know we're gonna need LOTS more pics of that scope... 
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Orion 3.6CA Reflector
and 2 homebrew scopes --
8" Hubble Bubble ballscope
8" F/8 CHief - nearing completion 
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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first light tonight after some adjusting it works THANKS ED FOR ALL THE HELP
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mark cowan
Vendor (Obsidian Optics)
Reged: 06/03/05
Posts: 2159
Loc: salem, OR
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"It works" ?
That's all?
Come on! 
Best,
Mark
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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hi MARK i need to spend some time tweeking the ajustments hope to tonight / verry cool / this thing works !!so easy a farmer can do it/ / i think it is the way to go!! ED says he can make it work up to 30 inches/ ED made the corrector lens and the upper end of the ladder // i made the f8 primary and the mounting / ED tested all the optics on his zygo.kevin frederick
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Congrats Kevin, I think you just set a record for the largest amateur unobstructed scope! 
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Ed Jones
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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You made the part that has neaver been made before!! // What can we build next? This telescope is so cool looking in the focuser and no secondary and spider// Canot wait to have you take a look// THANKS kevin frederick
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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I helped Kevin making the lenses, lensbox and upper ladder. Kevin did the mirror and everything else. Here's a picture of Kevin's lens box before painting.
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Ed Jones
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deSitter
Carpal Tunnel
Reged: 12/09/04
Posts: 2926
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When did "chief" become the handle for a Schiefspiegler (literally "Slantmirror-er")?
-drl
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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It's a name I coined, short for "Catadioptric-Herschelian Schiefspiegler" to distinguish it from the typical schief.
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Ed Jones
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deSitter
Carpal Tunnel
Reged: 12/09/04
Posts: 2926
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Nice!
-drl
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Gary Fuchs
scholastic sledgehammer
Reged: 05/22/06
Posts: 867
Loc: Easton, PA, USA
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Nice work both of you. I'm hoping to get a look soon.
Gary
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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just looked at the moon with the 20 f8 CHIEF / LOOKED great and i had not got all the adjustments done it/ MY wife was blownaway and she has looked through alot of telescopes/ KEVIN
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Glig
sage
Reged: 10/02/05
Posts: 370
Loc: Baltimore, MD
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Well I hope I don't ruffle any feathers here but the Chief seems to be king of all the tilted component telescopes. Can anyone name a type of TCT that is portable anywhere near this size other than the Chief? Most examples of TCT's I've seen are 4.25 inches in aperture! 6 inches is considered big!
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Richard Caldwell
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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There was an 18 inch Yolo in Feb. Sky & Tel 2008 built by Chris Krauskopf from Louiville.
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Ed Jones
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Glig
sage
Reged: 10/02/05
Posts: 370
Loc: Baltimore, MD
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My guess is that this Yolo has a high center of gravity -unlike your Chiefspiegler design. I might be just spittballing here but the high center of gravity most TCT's have (and high complexity) may limit their usefulness as portable telescopes. Because of that I doubt a Yolo of this size can be portable without a lot of engineering.
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Richard Caldwell
Edited by Glig (08/27/09 08:34 AM)
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Glig,
The issue is more that the Yolo and schiefs have the eyepiece on the bottom like a refractor which means that they need to be up on a GEM and tripod, makes it harder to mount in larger sizes. The Chief has the eyepiece higher, more like a Newt and can go on a Dob mount. Google 18 inch Yolo and you'll see the 18 inch Yolo, it's quite a monster.
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Ed Jones
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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here is a pic of my 20 inch f 5.25 newtonian with a 20inch f8 CHIEF / I TAKE THE CHIEF
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3455
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Nice job, Ed & Kevin! That pic of the 2 scopes together is very revealing! And nice to see some pic's of your work, Kevin! I imagine 20 unobstructed inches must make for some spectacular viewing.
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Wes
Atlantic Beach, FL
Some bino’s from Miyauchi 5x32 Binon's up through Garrett 20x110 Signature's,
Some telescopes from a Stellarvue 80mm NHNG up through a couple of 8” reflectors…
And a wonderful 4.25" Delmarva Shiefspiegler!
Some good friends, made here on C/N.
Oh- several cats and a wonderful wife!
Anyone want a cat???? :-O
"When your work speaks for itself- Don't Interrupt" -Gamble Rogers
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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EYEPIECE IS LOWER ON THE CHIEF // ALSO 21 INCHES OF IN FOCUS
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jayscheuerle
Post Laureate
Reged: 01/16/06
Posts: 4071
Loc: S. Philadelphia, PA
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From that pic, it looks like the Chief's top end would fall into the light path...
Is the primary tilted in relation to the base? - j
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Fight indignorance!
The Green Goblin - 12" of dobsonian excellence!
The PortaBowl-a $100 4.5" f/8 ball-scope YOU can build!
Eero2-a 6" f/5 ball-scope you probably can't.
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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ONE MORE
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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EVERYTHING IS TILTED ON THE CHIEF THE REFLECTED BEEM OF LIGHT RUNS PARRELL TO THE LADDER
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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No the upper rim ray runs roughly parallel to the ladder, the primary mirror is tilted in the box about 3.1 degrees and the axis reflects back double that.
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Ed Jones
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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the primary mirror edge nearest the ladder is about one inch lower than the other edge and about one inch away from the ladder /KEVIN
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RossSackett
professor emeritus
Reged: 08/17/07
Posts: 692
Loc: Memphis, TN
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Ed, I've been intrigued by your CHiefs since I first saw one at Stellafane. What is the minimum practical f-ratio for a CHief? I'd love to use the design for a minimalist 24" f/4.5 I am working on. Could one cheat it with a barlow to get a longer effective focal length, then use the tilted correctors to minimize the coma and stig caused by tilting the primary?
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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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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Ross you are the master of one arm telescopes bet you could take the chief to the next level /
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Ross,
No, I'm quite sure that won't work. F/4.5 is just too fast, I did an 8 inch at f/5 but that was pushing it, a 25 inch would need a longer f ratio. In the Chief longer f ratios actually fold the eyepiece back farther than shorter f ratios can even though the OTA may be longer. The eyepiece height is important for big scopes for avoiding ladders.
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Ed Jones
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RossSackett
professor emeritus
Reged: 08/17/07
Posts: 692
Loc: Memphis, TN
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Ed,
Yes, I see that you would still have a height issue, so we lose that advantage. But if you use a negative lens to double the effective f.l. can you use the correctors to gain the advantages of an obstructionless design?
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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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Ross,
No, short f ratios need high a tilt angle on the primary which is the limiting factor. A barlow wouldn't help. Now I haven't tried it in Zemax but I'm rather sure it won't fly.
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Ed Jones
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RossSackett
professor emeritus
Reged: 08/17/07
Posts: 692
Loc: Memphis, TN
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Thanks! No free lunch...
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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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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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ROSS the longer focus the lower the eyepiece
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RossSackett
professor emeritus
Reged: 08/17/07
Posts: 692
Loc: Memphis, TN
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Got it. Now if I only had a 24" f/10 mirror lying around...
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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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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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RUSS BE FUN TO GRIND ONE ONLY TOOK ME 5 MONYHS TO FINISH THE 20 F 8 MIRROR /I NEEDED 28FT FOR THE TEST/LOTS OF FUN
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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I MEANT TO SAY Ross
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gatorengineer
scholastic sledgehammer
Reged: 02/28/05
Posts: 882
Loc: Hellertown, PA
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Kevin,
Been following with alot of interest... Congrats.....
Mark
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20" F5 Dob
16" Dob in pieces
Comet Catcher
MN71
12" Doc Clay Sky Patrol MEADE SCT
12.5" F4 Newt under construction
Siebert 45mm Binoviewers
Lots of binos---
Optics Past - 8" Stf Mak, 4" B&W triplet, 6"Schmidt newt, 12"LX200, C8, Meade LX10-10", 10" MEADE ACF, SN8, TAL150K, Orion 150MC, Jason 60mm refractor, ATM 6" F8, WO 110FLT, 92mm Off Axis Newt, Televue Genesis, Nikon 20x120 bino's, 15x110 Boarderguards, Kuhne Flaks
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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it was no harder to build than any dob i had Ed make the top end / the telescope has alot of advantages / more every day i find /colomation is very easy with a laser / Verry cool looking in the focuser and seeing 20 inches clear optic / give ED a call before he gets too busy
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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almost every aspect the CHief has advantages f8 / unobstructed/ great baffeling/ 21 inches of in focus/ muchless secondary foging / less drang from the wind / very easy to sight down the lens box /
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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also if you have some astig in your primary the chief lens can take it out/ not sure why there is not more intrest in this designe /takes a regular newtonian mirror and a flat and two small single lens of bk7/ about as simple as unobstruted can get/
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3455
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Kevin-
How difficult did you find it to build the upper cage assembly- as far as aligning distances and axis between the mirrors/lens assemblies and the focuser? How critical are the alignments/initial positions of the lens assembly in relationship to the mirrors?
edit: I had to edit this post when "it" mistook my abbreviations for "assemblies" as foul language... gee, the software's not as smart as it might think it is!
Wes
Edited by Wes James (08/29/09 03:13 PM)
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3455
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Whoops- I just reread the posts here, and didn't realize before that Ed built the upper end of the scope.... is there a reason he built it? I'm just curious if it's a difficult build for the average person? Same question still as above- is it difficult to get everything in the correct planes/axis's?
Wes
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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alliment// put a lazer in the focuser so it hits the center of the secondary [flat] then adjust the flat so it hits the center of the primary then adjust the primary so the red dot hits a target 10 inches from the edge of the flat// the distance from focus to the first lens is needed/ then play with the tilts just like focusing a star / my primary is not coated / the moon looks unlike i have ever seen// the craders are BLACK very cool/ i have only had a little tine to adjust it // hope tonight i can get it out/
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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why i had ED make the upper end ? because i canot spell chiefsegler let alone know how IT WORKS //only ed and mike know that // you CANOT make a chief with out ED OR MIKE .
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3455
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Kevin- let us know how it star tests when you get a chance to spend a little more time with it, will you?? I'm sure the moon looks nice through it... unobstructed optics make for nice viewing. The first time I took my 4.25" Schief out, we were looking at a mountain along the terminator- the total blackness at the base of the mountain- the way it was shadowed made it look like the mountain was floating above the edge of the lunar surface... amazing!
Wes
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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THE TELESCOPE WORKS GREAT VERY GOOD /
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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the chief is so great i canot say enough of the images very nice// easy to use works just like a F8 newtonian Ed plus zemax = very cool telescope
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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a pic
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3455
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Looks like a beautiful place to observe from~ I envy you that~ Hope to have a place like that someday... in retirement in a couple of years... at least a place out in the country.
What do you like to observe? Are you lunar? Planetary? Deep Sky??
Wes
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dave brock
super member
Reged: 06/06/08
Posts: 165
Loc: Hamilton, New Zealand
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Can you still use a DSC system if the primary is tilted in relation to the altitude bearings?
Dave
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20" homebuilt truss dob
6" watson refractor
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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another pic
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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the lens box looks like a good place for a finder and maybe a cup holder // ha ha
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Mark Harry
Post Laureate
Reged: 09/05/05
Posts: 3125
Loc: Northeast
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Beer can holder!
M.
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So many projects, so little time!
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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hi mark the views are great// no need to make big newtonians any more/ HOW IS THE YOLO COMING?
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Dave,
I think the issue would be if the incoming otical axis is perpendicular to the bearing axis. I'm quessing that a DSC needs it to be perpendicular to work well (don't own a DSC). In this case it probably isn't but there's no reason it can't be when you build the mirror box and ladder system.
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Ed Jones
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wirenut
professor emeritus
Reged: 09/21/06
Posts: 566
Loc: m'dale Pa
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thats a very nice scope kevin. I bet the views are spectacular no spider no secondary. are planning on leaving the primary uncoated?
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8"GSO dob
8,17 mm hyperions & FT rings
21mm stratus
25,15,9 mm plossls
ultima barlow
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3455
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Orthogonality of optical axis are critical to accurate operation of go-to/push-to mounts. One of the claims that makers such as the Discmount and Half Hitch make is the accuracy of the CNC machining- contributing to the accuracy when used with digital setting circles such as the Sky Commander. (Though commercial dob's by Orion and others are so equipped)
Kevin- if your mirror(s) is/are uncoated, while you may be able to determine that the scope will come to focus- and even star test it- which you don't state you've done, and see the moon- which is not a difficult task for even a small 60mm scope to do- but I don't see how you can make claims about how amazing a scope it is- making other types of scopes obselete- when you haven't even coated the mirrors yet? The scope isn't completed!
Wes
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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no the telescope is not compleated / have not done much adjusting /the image is very nice //in my opion it will make a newtonian/ cass /and refractors all dust collectors/ kevin / come and see
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Orthogonality can easily be designed in if that's important to you. Some of us old foggies can still find things without a computer. 
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Ed Jones
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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WES THERE ARE SIX ED JONES CHIEF TELESCOPES WORKING// ALL WORK GREAT /BETTER THAN ANY OTHER TYPE// REFLECTOR OR REFRACTOR // AND EASY TO MAKE // AND SMALLER / NO COMA / NO COLOR / NO SECONDARY /SPIDER /AND DEFRACTION SPIKES // WHAT MORE DO YOU WONT ??KEVIN FREDERICK
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Wes James
Post Laureate
Reged: 04/12/06
Posts: 3455
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Quote:
Orthogonality can easily be designed in if that's important to you. Some of us old foggies can still find things without a computer.
*laughing* I have a sky commander on my Half Hitch... I have yet to use it!
Wes
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Zoomit
sage
Reged: 12/04/06
Posts: 282
Loc: Tehachapi, CA
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Quote:
WES THERE ARE SIX ED JONES CHIEF TELESCOPES WORKING// ALL WORK GREAT /BETTER THAN ANY OTHER TYPE// REFLECTOR OR REFRACTOR // AND EASY TO MAKE // AND SMALLER / NO COMA / NO COLOR / NO SECONDARY /SPIDER /AND DEFRACTION SPIKES // WHAT MORE DO YOU WONT ??KEVIN FREDERICK
Speed
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Brandon
Newts: 18" f/4.6; 7.4" f/6.4
EPs: TV 26Nt5, 13E, 3-6NZ; Antares 2" 1.6x, Paracorr
Bino: 15x70, 12x50, 6x30
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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yes the chief is slow / i like long focus mirrors
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Mason Dixon
member
Reged: 06/29/07
Posts: 43
Loc: Huntsville, Alabama
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Can a chief around 15" be F6?
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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looking at the moon tonight [ in the 20 f 8 chief] unlike i have ever seen it /unreal
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Quote:
Can a chief around 15" be F6?
Zemax says yes but you'll be pushing the tolerance envelope.
Ed
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Ed Jones
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DAVIDG
Carpal Tunnel
Reged: 12/02/04
Posts: 1987
Loc: Hockessin, De
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Quote:
looking at the moon tonight [ in the 20 f 8 chief] unlike i have ever seen it /unreal
Kevin,
I'm sure that the unobstructed optics of the CHIEF design are helping you get great lunar views but one other reason is because your 20" primary mirror is uncoated. In this stated there is very little scattered light which makes the views of the Moon give very high contrast. Companies like Webster Telescopes sell large Dobs with uncoated primaries just for lunar viewing because of this effect http://www.webstertelescopes.com/lunar.htm
- Dave
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Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schief. 60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4.5" f/16 Schupmann Medial refractor, 14 Stellafane awards 7 in optics
Engineering = Taking what you have and making what you need.
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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yes DAVE it is nice not so bright / i used a nangler 4.8 mm it was very clear very nice unlike my other 20 inch f5 or my 26 inch f5 i havenot messed with the adjustments or set it up correct but it works you will see very forgiving // ed does all that with two 4 inch lens// it is kind of like i am cheating geting a unobstructed telescope with less work than a newtonian // kevin
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Mert
Carpal Tunnel
Reged: 08/31/05
Posts: 1803
Loc: Spain, Pamplona
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Pics?????
Any image taken through the scope yet???? Please?
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Mert
42ş49"N 1ş38"W
3" Polarex refractor
6" F12 SW Maksutov,CS2-S
EQ6 + EQMOD 
SPC900NC/DFK21AU04.AS
My web-page don't laugh, I should make it better! 
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Wow! I haven't seen anyone that excited about a scope since I first looked through my first scope years ago. 
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Ed Jones
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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i am very excited when you look if you be to and you will agree we do not need obstructed big reflectors any more //
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Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
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Quote:
EYEPIECE IS LOWER ON THE CHIEF // ALSO 21 INCHES OF IN FOCUS
Lower EP height is a bonus but looking at that EP configuration looks like neck problems. Is it more comfotable to use than what it looks?
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Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
 My house.
 DRAACO
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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i use a right angle it work great that way not good straight through/
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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HOPE TO GET ED OR SOME OTHER ATM TO COME AND SEE /THERE NEXT TELESCOPE / MAYBE IAM GOING CRAZY / MAYBE TOO MANY YEARS /
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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primary mirror test
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Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
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Interesting design for sure, but having to make your own lenses for the corrector will keep a 'Cheif' on the very distant horizon for me. That's a little over my head right now.
--------------------
Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
My house.
DRAACO
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timo4352
super member
Reged: 04/16/07
Posts: 160
Loc: Northeast Ohio
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Biff
Ed has posted a few files on the spiderless group that use all commercial optics. That's the way I'm going. Can't wait to get my first look through mine
Tim
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Orion 3.6CA Reflector
and 2 homebrew scopes --
8" Hubble Bubble ballscope
8" F/8 CHief - nearing completion
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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i had Ed make mine they are 4 inches / going out to eds to have him take a look /kevin
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mark cowan
Vendor (Obsidian Optics)
Reged: 06/03/05
Posts: 2159
Loc: salem, OR
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Smaller sizes can use off-the-shelf lenses, and it will improve the light throughput as well, due to the prohibitive expense of getting AR coatings done on small quantities. But of purchased-then-reworked lenses 2 can be left coated and flat on purchased reworked lenses, which I understand Ed did in Kevin's case.
I think what's not obvious in the side by side pics is that the one on the left is a 20" f/5.2 (IIRC), and so is about 90" tall.
Kevin called me up to talk (rave?) about the lunar views this last Saturday - I think he was jumping up and down at the time. I know he's seen the moon many times with good optics, but he was obviously blown away by the views that the untweaked Chief was delivering - 20" unobstructed? Get outta here! I know what he's talking about with this setup, now, and I'm seriously thinking on making a smaller Chief for myself.
BTW, Ed has indicated in a couple of posts on the Spiderless group that a Chief can be made down to 8" f/5.6, and that with fluorite glass as an option the correction improves. I don't have any details about that, but am very curious, as I wonder - given similar FOV, can this be an APO killer with an excellent set of mirrors and custom made corrector lenses?
Best,
Mark
Edited by mark cowan (09/01/09 12:42 AM)
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llanitedave
Humble Megalomaniac
Reged: 09/26/05
Posts: 12939
Loc: Amargosa Valley, NV, USA
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I'm not sure that fast is the major goal here. What impresses me is that you have a nice, comfortable, slow scope with forgiving optics with large aperture and manageable tube length. That's a revolution in my book!
--------------------
"Since the process of science generates more mysteries than it solves, I predict that we'll never learn everything: and we'll continue to generate new ignorance at the speed of knowledge."
"S.O.E." (Sauron's Other Eye), with 16" Royce conical mirror: A permanent work in progress.
10" Homebuilt dob, old Coulter mirror
Under Construction: The "Eye of Sauron" Observatory!
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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very happy the way this works/ going to ED JONES house today so he can look / and then off to OMI to have it coated and let JAMES have a look .so this might be my last post before i get back/ very excited/ kevin frederick
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davidpitre
Carpal Tunnel
Reged: 05/10/05
Posts: 1824
Loc: Central Texas
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So how much chromatic aberration does this have ?
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David
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Light from 420 through the red falls inside the Airy disk.
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Ed Jones
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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I got a chance to look through Kevins Chief last night. He stopped by on his trip out to Iowa to get his primary coated. The sky was very clear but not very steady because of the cold front that came through. I forgot what it was like to look through a scope with an uncoated mirror and was surprised how bright the moon and Jupiter looked. We were pretty much seeing limited but occasionally the seeing would improve momentarily and show some good detail. He had some runnout issues with his laser but we were still able to get it aligned quite well. Stars were nice and round and I didn't see any prisimatic axial color to be adjusted. All in all even though we were seeing limited I am sure on a good night the scope should show a good image at 850 power that Kevin said he was doing. He has a few mechanical details to iron out but not optically, good job Kevin!
We were in the local park and later a squad car came by to check out this strange contraption and us. We laughed and were finished anyway then packed up.
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Ed Jones
Edited by Ed Jones (09/02/09 10:49 AM)
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gatorengineer
scholastic sledgehammer
Reged: 02/28/05
Posts: 882
Loc: Hellertown, PA
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Hope Kevin knew you can get a 20" coated in New Jersey....
Nice time of the year for a road trip though.....
--------------------
20" F5 Dob
16" Dob in pieces
Comet Catcher
MN71
12" Doc Clay Sky Patrol MEADE SCT
12.5" F4 Newt under construction
Siebert 45mm Binoviewers
Lots of binos---
Optics Past - 8" Stf Mak, 4" B&W triplet, 6"Schmidt newt, 12"LX200, C8, Meade LX10-10", 10" MEADE ACF, SN8, TAL150K, Orion 150MC, Jason 60mm refractor, ATM 6" F8, WO 110FLT, 92mm Off Axis Newt, Televue Genesis, Nikon 20x120 bino's, 15x110 Boarderguards, Kuhne Flaks
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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The coating wasn't the only reason for his trip I believe.
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Ed Jones
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Mike I. Jones
Carpal Tunnel
Reged: 07/02/06
Posts: 1572
Loc: Fort Worth TX
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Wonder if it was the same policeman that answered the call when I hit that deer near your house! He was a nice enough guy but when he asked us to step back because he might have to shoot the dying deer right in that guy's driveway, I began to wonder some about him.
Congrats Kevin AND Ed! Good to hear the star images were round and sharp. I bet the moon/planetary imagery did look good - an uncoated 20" is about the same brightness as a 3.75" coated mirror or a 95mm refractor - plenty of light!
Mike
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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This cop looked a little like Barney Fife, maybe it was the same guy, glad he didn't pull a gun! I'll bet he was curious what 2 old geezers were doing in a public park, at midnight with some strange looking wooden thing.
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Ed Jones
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kingjamez
scholastic sledgehammer
Reged: 10/03/06
Posts: 991
Loc: Washington D.C.
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Is F8 an optimal focal length at 20"? I've got a 25" pyrex blank that has been sitting around waiting for a project. The thought of 25" F/4.5 made me shutter, but 25" F/8 is within even my limited skill set.
Are there any references for optimal "Chief" designs?
-Jim
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C8 on Atlas with EQMOD
ETX125 UHTC
Celestron Onyx 80mm
Meade Walmart 60mm guide scope
Canon Xsi Modified w/IDAS LPR
Gen 3 NightVision Eyepiece
Aspiring Optician
Watch my Wiimote control Atlas:
http://www.youtube.com/watch?v=PnmkygmGNiM
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Yes f/8 would be easier to parabolize and test than an f/4. How are you at making lenses, these you would have to make?
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Ed Jones
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perfessor
sage
Reged: 12/30/07
Posts: 499
Loc: Northern Illinois
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Quote:
Are there any references for optimal "Chief" designs?
My thoughts also.
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Tom
"Don't always know what I'm talkin about"
8" f/7
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Biff
Carpal Tunnel
Reged: 09/04/05
Posts: 2372
Loc: Courtice, Ontario
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Shot in the dark here Ed, but you wouldn't happen to have any 10" designs with commercial lenses do you? Not picky about F ratio really.
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Ryan
Antares 200mm f/6 Dob & 130mm f/5 Travel Dob.
Projects on the go...
- a couple 80mm SS refractors on the back burner.
- a few small mirrors awaiting polishing
- 260mm f/7.15 mirror... still polishing
Member of DRAA
My house.
DRAACO
|
Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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No sure what anyone would call optimum, there are an infinite number of possible lens combinations and different ways you can fold the light path. Practically speaking the biggest issue is where will you get the lenses. The commercially available lenses put restrictions on the possible designs. There are no written references as the design is too new.
Biff,
No I don't have a design but send me a PM and I can discuss the issues with a 10 inch using commercial lenses.
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Ed Jones
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kingjamez
scholastic sledgehammer
Reged: 10/03/06
Posts: 991
Loc: Washington D.C.
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Ed,
I've not made lenses before, but have the machinery, and some expert knowledge within driving distance (DAVIDG, and Guy Brandenburg are not far away).
This sounds like my next BIG project. Thanks for leading the bleeding edge!
-Jim
--------------------
C8 on Atlas with EQMOD
ETX125 UHTC
Celestron Onyx 80mm
Meade Walmart 60mm guide scope
Canon Xsi Modified w/IDAS LPR
Gen 3 NightVision Eyepiece
Aspiring Optician
Watch my Wiimote control Atlas:
http://www.youtube.com/watch?v=PnmkygmGNiM
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Holy cow, a 25 inch Chief! Old Herschel will be smiling from the grave!  You need to get with me or a designer before you start.
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Ed Jones
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kingjamez
scholastic sledgehammer
Reged: 10/03/06
Posts: 991
Loc: Washington D.C.
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Oh, I will. I have a few other smaller optics to finish first. I'll PM you with some questions if you don't mind.
-Jim
--------------------
C8 on Atlas with EQMOD
ETX125 UHTC
Celestron Onyx 80mm
Meade Walmart 60mm guide scope
Canon Xsi Modified w/IDAS LPR
Gen 3 NightVision Eyepiece
Aspiring Optician
Watch my Wiimote control Atlas:
http://www.youtube.com/watch?v=PnmkygmGNiM
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Sure, no problem. 
--------------------
Ed Jones
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johnnyha
Pooh-Bah
Reged: 11/12/06
Posts: 1118
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Awesome!
I understand that the primary is tilted but I am still having trouble understanding how the light path is able to clear the upper assembly?
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Johnny
Spicewood, TX
Sherman Oaks, CA
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Zoomit
sage
Reged: 12/04/06
Posts: 282
Loc: Tehachapi, CA
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The primary mirror, in Kevin's implementation, is tilted *outward* from the upper assembly. It is not level like a Newt or inward like you might think at first. Considering it another way, the upper assembly is not aligned to the point in the sky the telescope is viewing.
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Brandon
Newts: 18" f/4.6; 7.4" f/6.4
EPs: TV 26Nt5, 13E, 3-6NZ; Antares 2" 1.6x, Paracorr
Bino: 15x70, 12x50, 6x30
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johnnyha
Pooh-Bah
Reged: 11/12/06
Posts: 1118
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Brandon thanks. So the primary is tilted outwards... I'm not sure I understand how it is that the focal plane shifts back over to the mirror flat at the upper end? Forgive my ignorance on this subject I may have my terminology wrong but I'd love to understand this. Do you collimate on a different spot than the center of the mirror or what is the secret?
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Johnny
Spicewood, TX
Sherman Oaks, CA
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perfessor
sage
Reged: 12/30/07
Posts: 499
Loc: Northern Illinois
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Johnny, I think I see your confusion - the primary is tilted toward the secondary - as a result, the field of view is tilted away from the secondary. That is how it "misses" the secondary support arm.
--------------------
Tom
"Don't always know what I'm talkin about"
8" f/7
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johnnyha
Pooh-Bah
Reged: 11/12/06
Posts: 1118
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Tom - is there any residual coma from this?
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Johnny
Spicewood, TX
Sherman Oaks, CA
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Not great resolution but like this.
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Ed Jones
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johnnyha
Pooh-Bah
Reged: 11/12/06
Posts: 1118
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So Ed does this require a special primary?
Oh - or is there a bit of coma or astigmatism or whatever that is corrected by the tilted lenses?
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Zoomit
sage
Reged: 12/04/06
Posts: 282
Loc: Tehachapi, CA
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Thanks Ed--This is where a picture is worth more than a few paragraphs.
johnnyha--No special primary is needed, just a standard parabola.
--------------------
Brandon
Newts: 18" f/4.6; 7.4" f/6.4
EPs: TV 26Nt5, 13E, 3-6NZ; Antares 2" 1.6x, Paracorr
Bino: 15x70, 12x50, 6x30
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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got back from seeing ED and a trip to OMI ,JAMES has a dream shop lots of glass being worked //very cool to see the mirror be coated / JAMES took time to do some STARS with the big CHief/ very cool having ED and james take a look/ we donot have to use obtructed reflectors any more . kevin
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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ED JONES AND THE 20 OFFAXIS CHief
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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the end may be near/ for what we hold dear/ but do not fear the CHief is here /
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mark cowan
Vendor (Obsidian Optics)
Reged: 06/03/05
Posts: 2159
Loc: salem, OR
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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JAMES MUHERIN and the 20 inch offaxis CHief ready for star test
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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JAMES HAS SOME THOUGHTS ON THE CHIEF DESIGNE ON TORUSMIRROR YAHOO GROUP
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tim53
Pooh-Bah
Reged: 12/17/04
Posts: 1454
Loc: Highland Park, CA
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I didn't find that yahoogroup when I searched for "torusmirror"
-Tim.
--------------------
"We`re just waiting looking skyward as the days come down.
Someone promised there`d be answers, if we stayed around."
-Orchestral Maneuvers in the Dark, "The Romance of the Telescope"
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tim53
Pooh-Bah
Reged: 12/17/04
Posts: 1454
Loc: Highland Park, CA
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okay found it when I put a space between torus and mirror.
Have to join, though.
--------------------
"We`re just waiting looking skyward as the days come down.
Someone promised there`d be answers, if we stayed around."
-Orchestral Maneuvers in the Dark, "The Romance of the Telescope"
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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I ask ED JONES will a CHief made correct give a better image than a newtonian/ And ask JAMES MUHERIN the same // they said yes /
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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HAD the 20 out last night and spent some time with the adjustments was working good/ better than when james and ED used it/ jupiter looked nice / fun telescope
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mark cowan
Vendor (Obsidian Optics)
Reged: 06/03/05
Posts: 2159
Loc: salem, OR
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Nice? How nice?
Mark
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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the sky is very dark and the stars are very nice/ This type telescope has more adjustments/ i am learning what not to do / very cool adjusting astig in and out / workes like a 20 f 8 newtonian only shorter // i love the way it works/kevin frederick
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PitchHitter
member
Reged: 09/23/09
Posts: 23
Loc: Southern Sierras
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Yes the optical axis needs to be parallel to the altitudinal axis. As it is this scope cannot view a 12 degree circle straight overhead unless modified.  So DSCs are out.
I havent seen any specs or references, where might they be found?
--------------------
About 20 telescopes from a 200mmAPO up
Fav is Meade 10" f:4.5 using my 3" 40mm 96°AFOV
BUT! In Progress:
14.5" f:5 grab n' go with DSCs will offer 2.4 degrees at 45 power and 8mm exit pupil (Light Bridge Buster)
16.25" f:7.5 to refigure
(20th wave ruined in a fire at the coaters)
22" f5: New mount almost done
(old all aluminum mount was stolen)
16" Varian Vapor Deposition Coater.
Looking for larger chamber.
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PitchHitter
member
Reged: 09/23/09
Posts: 23
Loc: Southern Sierras
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Hmmm Still it would be nice to be able to look straight over head. My 14.25" Grab n Go will have DSC's on them because I can program comets and other moving objects in. I also can't claim to finding all 14 thousand objects from memory. That way when I go to a function I don't have to worry about some smartaleck kid asking to see some obscure object.
--------------------
About 20 telescopes from a 200mmAPO up
Fav is Meade 10" f:4.5 using my 3" 40mm 96°AFOV
BUT! In Progress:
14.5" f:5 grab n' go with DSCs will offer 2.4 degrees at 45 power and 8mm exit pupil (Light Bridge Buster)
16.25" f:7.5 to refigure
(20th wave ruined in a fire at the coaters)
22" f5: New mount almost done
(old all aluminum mount was stolen)
16" Varian Vapor Deposition Coater.
Looking for larger chamber.
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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i think you are not taking in to acount. The mirror is not being used onaxis the object being looked at is not where the mirror is aimed of not where the ladder is aimed //had a hard time when i first tried to find the moon /and wondered why it looked funny /i took out the eyepiece and looked i was looking through a tree / i think a dsc will work// but not sure // be nice to have DSC on the chief /
also not sure about the dob hole at the top of the sky being bigger in the chief / interesting/ I think the large CHief is where ED JONES invension has the greatest potential //there is a lot of way to go unobtructed 10in and smaller /20+ inches unobstructed easy if you have ED JONES AND MIKE JONES /fun telescope /
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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a neet idea ED uses on his window chief . is aim a green laser in the focuser it bounces off the two mirrors and up at the sky as a finder/ we donot have to have obstructed telescopes any more /i love newtonians and for the money and the views they canot be toped / the thing that got me excited was that how good the ofaxis can be and easy to make/ for very little money /two small bk7 lens / kevin
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Ed Jones
Pooh-Bah
Reged: 04/06/04
Posts: 1415
Loc: Sin-sin-atti
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Quote:
As it is this scope cannot view a 12 degree circle straight overhead unless modified.
That's only the way the way it was built. If it's really that important you can build it for a DSC. For me I have no blind spot since I always use it with an equatorial platform.
--------------------
Ed Jones
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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One thing this 20 INCH CHief does is DEEP SKY . When you think of offaxis you think of planets / Big unobstructed easy with EDS corrector/ KEVIN FREDERICK
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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going to be making a 6 inch f 10.75 CHief I have the primary. and have a idea on mounting the corrector different on this one . kevin
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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EDs says he could make a corrector to make the 48 inch f 10 that HERSCHEL made work. SO sounds like CHiefs are good to go to 50 inches . here is a pic of the finished 20 inch f 8 hand held camera.
Edited by kfrederick (10/28/09 11:21 AM)
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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a zygo same mirror
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kfrederick
professor emeritus
Reged: 02/01/08
Posts: 666
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Had the astronomyclub pres over to see the offaxis 20 it was working great .the new laser i got off howie helped .jupiter lookes great at 425 . i see if steve will post what he saw/
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