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Equipment Discussions >> ATM, Optics and DIY Forum

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MKV
Carpal Tunnel
*****

Reged: 01/20/11

Re: Why no CHiefs intrest??? new [Re: Mike I. Jones]
      #5599597 - 01/01/13 01:13 PM

Quote:

Less of the light path crosses through itself, thus reducing in-tube convection effects



On a different thread (the Herrig) the light crosses its own path three times, but convection effects were never mentioned, IIRC. How damaging are such effects?

Mladen


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Mike I. Jones
Post Laureate
*****

Reged: 07/02/06

Loc: Fort Worth TX
Re: Why no CHiefs intrest??? new [Re: MKV]
      #5599625 - 01/01/13 01:29 PM

Th mutual paths are a lot shorter than for a Newt. I'll let you know when I build my 8" Herrig.

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Ed Jones
Carpal Tunnel
*****

Reged: 04/06/04

Loc: Sin-sin-atti
Re: Why no CHiefs intrest??? new [Re: Mike I. Jones]
      #5599806 - 01/01/13 03:17 PM

I agree with you Mike except that I don't find alignment much of a problem. It is a learned skill needing instruction but I can use a simple laser and get dependable results. That's not true with a fast Newt where you need a barlowed laser, a simple laser just isn't accurate enough. Slower systems usually have looser tolerances.

If there is enough demand for a product people want someone will produce it.


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kfrederick
Carpal Tunnel


Reged: 02/01/08

Re: Why no CHiefs intrest??? new [Re: Ed Jones]
      #5599825 - 01/01/13 03:28 PM

+1

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MKV
Carpal Tunnel
*****

Reged: 01/20/11

Re: Why no CHiefs intrest??? new [Re: Mike I. Jones]
      #5599829 - 01/01/13 03:30 PM

Quote:

Th mutual paths are a lot shorter than for a Newt. I'll let you know when I build my 8" Herrig.



Yes, Mike, the paths are shorter but there are more of them in this case. I was hoping you could direct me to a study done on the effects of path crossing, rather than tell me to wait for your to build the Herrig - given that the Herrig is last on your bucket list! Gee, then, I guess neither one of us knows how bad this path crossing is, do we? I'll look elsewhere. Thanks.

Mladen


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kfrederick
Carpal Tunnel


Reged: 02/01/08

Re: Why no CHiefs intrest??? new [Re: MKV]
      #5600174 - 01/01/13 07:18 PM Attachment (20 downloads)

Corrector data Mike work

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kfrederick
Carpal Tunnel


Reged: 02/01/08

Re: Why no CHiefs intrest??? new [Re: kfrederick]
      #5600188 - 01/01/13 07:26 PM Attachment (34 downloads)

Primary data

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Dave O
sage
*****

Reged: 12/21/11

Loc: Sri Lanka
Re: Why no CHiefs intrest??? new [Re: kfrederick]
      #5600328 - 01/01/13 09:01 PM

Quote:

Dave O did a great paper explaining a 10 inch I hope he will post it .




That little document was created for Jack S, and is specific to his CHief; he has added some more information from an actual construction point-of-view (again specific to his design). As far as I am concerned, it is his document now, and he is free to do with it as he likes.


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StarryHost
member
*****

Reged: 01/13/09

Loc: Vista, CA
Re: Why no CHiefs intrest??? new [Re: Dave O]
      #5600466 - 01/01/13 10:29 PM

Ooops! I just saw this thread. I will dig up the document and publish tonight if I can. The combined effort of several people is represented in it and it should encourage the art of the CHief.

As for me, I've got my long focus Newt now and it's just massive. The CHief is still attractive for me and now that I have my newt, I can go back to stabilizing the problems I had with the mount and CHief's upper OTA.

Kevin's concept of the waterjet upper OTA is I think really good for those of us who are intimidated by field collimation. Ed assures us that the skill is learnable and not necessary every single time, but I am cautious.

I'll post the document in a bit.

Thanks,
Jack Swaton
www.StarryHost.com


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StarryHost
member
*****

Reged: 01/13/09

Loc: Vista, CA
Re: Why no CHiefs intrest??? new [Re: StarryHost]
      #5600488 - 01/01/13 10:43 PM

OK. Here is The Document...but it is too big to post.

If you want a copy, please email me at jack.swaton@starryhost.com. :-)

This document has contributions by Dave and Mike and Kevin. The document is part narrative and part compilation of emails.

I don't have the time to clean it up anymore right now, but I am saving it for my assured return to the CHief.

Enjoy. If you have questions, I will do my best to answer.

Ed,
If you have feedback for this doc, please by all means let me know.

Best,
Jack Swaton
www.StarryHost.com


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Mike I. Jones
Post Laureate
*****

Reged: 07/02/06

Loc: Fort Worth TX
Re: Why no CHiefs intrest??? new [Re: StarryHost]
      #5600491 - 01/01/13 10:46 PM

Jack,
Could you email it to my Yahoo account?
Thanks,
Mike


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StarryHost
member
*****

Reged: 01/13/09

Loc: Vista, CA
Re: Why no CHiefs intrest??? new [Re: Mike I. Jones]
      #5600495 - 01/01/13 10:52 PM

Done! The email is winging it's way through cyber space even as we speak.

Jack


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mark cowan
Vendor (Veritas Optics)
*****

Reged: 06/03/05

Loc: salem, OR
Re: Why no CHiefs intrest??? new [Re: Mike I. Jones]
      #5600584 - 01/02/13 12:26 AM

Quote:

5. Cost versus benefit/sales volume - Can Chiefs really be commercially made at any useful sales volume or profit margin? Kevin's Chief has set the bar in Chief size and quality that may never be beaten. But could he make an order of, say, 250 units, and make anything like a profit? I would estimate no, it would not be a profitable commercial product.




I'll address that, while noting that yes, just setting up a Newtonian properly defeats a lot of people.

As a mirror maker, there's mostly one surface (the primary) that I'd make any profit on. The other components are farmed out (certainly in the case of Kevin's 17"). There's just not enough return from a long f/ratio primary, even with hyperboloid correction, to make it worth pursuing. Yes, one for myself, cool, I'd like to have it. Try to make them to sell (optics sets or finished scopes), no way. The user support could indeed be a killer.

CO vs no CO? Definitely I come down on the unobstructed side. But I have my own redesign of the Stevick-Paul on my list that's mountable and all mirrors, something I'm make first at a 14" size. It has the advantage...wait for it...that I fiddled around optimizing a new take on the SP that could be supported in a standard sort of dob structure.

I'd like to see the Traveling Chief Road Show. Set that thing up at OSP next fall and there'll be a LOT of interest. But until the eyes meet the EP it's difficult to commit the units that commercial manufacture would require. This is one for the converts, long standing or newly minted from handy materials...

Kevin has done a great thing in making the lens-box assembly available to anybody at about his cost, I think he's right that this simplifies it to the point of ease. Not sure if he's publicized that very much yet - uhm, or if he really intended that and wasn't just talking to me - though we have discussed it. But the $2.5K or so for the 17" lens set (less in qty) is still a stickler, and ya know those probably really do need to be coated for throughput (not reflections) and that's pricey.

This is not in any particular order. But I'd like to see Kevin talk on about his experiences with this thing because he's the one that's been pushing on with it to see the fulfillment of the no-compromise large unobstructed design that this is.

Best,
Mark


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Mike I. Jones
Post Laureate
*****

Reged: 07/02/06

Loc: Fort Worth TX
Re: Why no CHiefs intrest??? new [Re: mark cowan]
      #5600604 - 01/02/13 12:52 AM

+1 from me on that, Mark!

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dave brock
professor emeritus


Reged: 06/06/08

Loc: Hamilton, New Zealand
Re: Why no CHiefs intrest??? new [Re: kfrederick]
      #5600728 - 01/02/13 04:41 AM

Quote:

Why no interest in the Ed Jones Chief design ?




A question for you Kevin.
Would you have your 20" Chief if you didn't have Ed to make the lenses?

Dave


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kfrederick
Carpal Tunnel


Reged: 02/01/08

Re: Why no CHiefs intrest??? new [Re: dave brock]
      #5600764 - 01/02/13 06:47 AM

There would be no Chiefs with out EDs work. He showed me how to set them up .. Mike came up with the idea for the hyperbolic chief .And the slotted box set up is mine.

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kfrederick
Carpal Tunnel


Reged: 02/01/08

Re: Why no CHiefs intrest??? new [Re: kfrederick]
      #5600815 - 01/02/13 07:54 AM

Could a CHief be made using a concave secondary mirror?

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kfrederick
Carpal Tunnel


Reged: 02/01/08

Re: Why no CHiefs intrest??? new [Re: kfrederick]
      #5600823 - 01/02/13 08:00 AM

http://www.gmto.org/ I wonder if the Chief corrector would help these guys TEST there offaxis mirrors. They said how hard it was to have a test for the outside mirrors .

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Mike I. Jones
Post Laureate
*****

Reged: 07/02/06

Loc: Fort Worth TX
Re: Why no CHiefs intrest??? new [Re: kfrederick]
      #5600929 - 01/02/13 10:11 AM

I think Ed's use of a flat secondary is the easiest. The bend angle after the secondary can be set to any value convenient for observing. Its flat surface removes it from any contributions to system aberrations other than tilt misalignment. I haven't built one, but ZEMAX tolerancing tells me Ed's Chief is simpler to align, and more tolerant to structural flexure as the scope is aimed from horizontal to vertical.

Your 17" Apo-Chief has a long-radius convex secondary, which forces your bend angle to a single value. But combined with the hyperboloidal primary, the convex secondary was what allowed the last bit of correction over your FOV.

Kevin, I think the 17" Apo-Chief you have built is one of the most remarkable achievements in ATM history, right up there with Russ Porter's Springfield mount, TCT's like the Stevick-Paul and Schupmann, the Houghton and Schmidt configurations, and the Dobson mount. I would say its design and fabrication may remain unique in history, even with the other Chiefs being built.

I agree with Mark Cowan that it's well worth taking around the country and showing at major star parties. I don't know when, but I do look forward to viewing through it on some still, quiet night with good seeing and transparency.

Mike


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Mike I. Jones
Post Laureate
*****

Reged: 07/02/06

Loc: Fort Worth TX
Re: Why no CHiefs intrest??? new [Re: StarryHost]
      #5600979 - 01/02/13 10:38 AM

WAAOWW! I had no idea Dave went to that much trouble to document Jack's scope. Outstanding writeup!
Mike


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