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Equipment Discussions >> Reflectors

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cwilson
super member


Reged: 10/01/12

Loc: SW Oklahoma
Long Focus Newts?
      #6488803 - 04/25/14 09:13 PM

Does anyone sell high quality long focus Newts these days? Say something like a 6" f/8?

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jzeiders
sage


Reged: 11/07/12

Loc: SF Bay Area
Re: Long Focus Newts? new [Re: cwilson]
      #6488960 - 04/25/14 11:10 PM

You can check with a top mirror maker and see what the rice would be for a custom mirror, You could also make your own, An f/8 is fairly easy and once you make your own there is nothing quite like first light with a mirror you made. Don't worry about better than 1.4 or 1.8 wave, that is plenty if you have a smooth curve, a good edge (not turned) and are fully polished out.

Back in the early '70s I made an 8" f/8 and it was a wonderful scope. Planets and doubles were wonderful and deep sky was just fine. The long tube was a bit of a hassle but not really a big deal. Ray trace it and make a set of baffles for it, it makes a big difference in contrast. Also use a good quality secondary.

I think Orion sells or did sell a 6" f/8 dob. How good are they? I dunno.

Jack


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ylem
sage


Reged: 01/27/09

Loc: Monroe, NC
Re: Long Focus Newts? new [Re: cwilson]
      #6488966 - 04/25/14 11:14 PM

Other then the Orion xt6, I don't think so......
I hope I'm wrong and others will let us know where to look


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youngamateur42
Carpal Tunnel
*****

Reged: 11/21/12

Loc: La Verne, CA
Re: Long Focus Newts? new [Re: ylem]
      #6488979 - 04/25/14 11:18 PM

If want to go a different route, you can get an old Criterion RV-6 for a relatively good price. They are excellent scopes, and the tracking is a plus. I love mine.

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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Long Focus Newts? new [Re: youngamateur42]
      #6489028 - 04/25/14 11:55 PM

Orion's xt6 has its fans to be sure. Refurbishing an old classic like RV6 would be a fine project too - particularly with the dandy coatings out there today.

Long focus newts aren't the rage they were back in the 60's as most observers these days are deepsky fans preferring larger aperture that would make f/8 impractical. My own 8" f/9 was a custom order from PARKS.

Like refractor fans, long focus reflector fans love the views specific to it.

Pete


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TCW
Pooh-Bah


Reged: 11/05/13

Loc: The North 40
Re: Long Focus Newts? new [Re: cwilson]
      #6489051 - 04/26/14 12:24 AM

Check out RF Royce.

http://www.rfroyce.com/ultimate%20newtonian.htm


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Jeff Morgan
Postmaster
*****

Reged: 09/28/03

Loc: Prescott, AZ
Re: Long Focus Newts? new [Re: TCW]
      #6489071 - 04/26/14 12:55 AM

Quote:

Check out RF Royce.

http://www.rfroyce.com/ultimate%20newtonian.htm




Bob Royce makes an excellent mirror (I have owned four of them over the years), and he still has mirrors as small as 6" on his price list. I am pretty sure he would do the slightly longer f/8 on a custom basis.


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TCW
Pooh-Bah


Reged: 11/05/13

Loc: The North 40
Re: Long Focus Newts? new [Re: Jeff Morgan]
      #6489110 - 04/26/14 01:54 AM

Check out these threads.

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/6080213/page...


http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/6266266/page...


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ylem
sage


Reged: 01/27/09

Loc: Monroe, NC
Re: Long Focus Newts? new [Re: TCW]
      #6489359 - 04/26/14 08:39 AM

Ahhh, life in the slow lane

My fastest scope is f8


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herrointment
Post Laureate
*****

Reged: 03/12/11

Loc: North of Hwy. 64
Re: Long Focus Newts? new [Re: ylem]
      #6490081 - 04/26/14 02:59 PM

I purchased a 1980's homemade 8" f/8.5 Newtonian on a Meade Starfinder mount for $250.00 a few years back.

When conditions are good you can hardly tear yourself away from the eyepiece.

It IS a planet killer!


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Jeff Morgan
Postmaster
*****

Reged: 09/28/03

Loc: Prescott, AZ
Re: Long Focus Newts? new [Re: herrointment]
      #6491138 - 04/27/14 01:35 AM Attachment (46 downloads)

My old 10" f/9 is still the only telescope to show me spokes in Saturn's rings. Chicago optician Dan Joyce and I both saw them at the Astrofest star party.

I do have high hopes for my Zambuto mirrors - one is a 16" f/7, the other in process is a 8" f/9.

Here is the old 10" at the Winter Star Party, circa 1997.


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precaud
Pooh-Bah
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: Long Focus Newts? new [Re: Jeff Morgan]
      #6491381 - 04/27/14 08:08 AM

I love that pic, Jeff. It makes me think of building something like that for use at home, I don't think I'd want to haul it around. Some kind of motorized observing chair would be nice too.

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Jeff Morgan
Postmaster
*****

Reged: 09/28/03

Loc: Prescott, AZ
Re: Long Focus Newts? new [Re: precaud]
      #6491494 - 04/27/14 09:55 AM

Thanks John. Selling that scope was one of my biggest astronomy mistakes ever.

I decided to rectify that by building a 8" f/9 scope. The aperture, true field, and focal length were chosen as a bridge between my 16" f/7 and a 4.7" apo refractor. I should be able to use it from a sitting position using a CatsPerch chair.


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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Long Focus Newts? new [Re: Jeff Morgan]
      #6491587 - 04/27/14 10:56 AM

You'll like the f/9 and the tube at a mere 35lbs is long but light to carry. Its never a bother. By contrast the heft of a 10" f/5 or bigger is significant heavier. I do use a simple step ladder but its a step up only. Its never a climb. The seat I'm making -an aspen chair- ought to be all that.



Pete

Edited by azure1961p (04/27/14 10:56 AM)


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Sean Cunneen
Let Me Think
*****

Reged: 08/01/07

Loc: Blue Island Illinois
Re: Long Focus Newts? new [Re: azure1961p]
      #6491635 - 04/27/14 11:17 AM Attachment (23 downloads)

They are out there. The good news is that long focus optics tend to be less expensive, but they are rare and don't come p for sale often. If you get your hands on some, they are potent performers!

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cwilson
super member


Reged: 10/01/12

Loc: SW Oklahoma
Re: Long Focus Newts? new [Re: Sean Cunneen]
      #6492025 - 04/27/14 03:06 PM

I live in an apartment so ATM is not practical for me. But I remember the great views I got many years ago from an 6" f/9 that my uncle built. He had access to an optical shop at a major university, so it was of very high quality. It was a great scope!

I was thinking having something along those lines would make a great planetary scope. Far less costly then a larger refractor.


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azure1961p
Postmaster
*****

Reged: 01/17/09

Loc: USA
Re: Long Focus Newts? new [Re: cwilson]
      #6492199 - 04/27/14 04:49 PM

I disagree,

Being an apartment dweller would seem to make ATM design and fab a solve for those issues particular to your dwelling needs.

Pete


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cwilson
super member


Reged: 10/01/12

Loc: SW Oklahoma
Re: Long Focus Newts? new [Re: azure1961p]
      #6492315 - 04/27/14 05:53 PM

Quote:

I disagree,

Being an apartment dweller would seem to make ATM design and fab a solve for those issues particular to your dwelling needs.

Pete




The problem is lack of workspace. It's pretty small.


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precaud
Pooh-Bah
*****

Reged: 12/05/12

Loc: north central New Mexico
Re: Long Focus Newts? new [Re: cwilson]
      #6492361 - 04/27/14 06:14 PM Attachment (21 downloads)

Oh, don't let that stop you, living rooms make great workshops in the absence of other available spaces. Of course, it helps not having a partner to ask permission from This is the 14 foot long solar heater I built in the living room, it was the only indoor place I could build it AND maneuver the finished unit outside from. Thankfully, I thought of that before I started on it!

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figurate
super member


Reged: 02/09/13

Loc: Metro North Texas
Re: Long Focus Newts? new [Re: precaud]
      #6492695 - 04/27/14 09:14 PM Attachment (18 downloads)

Do you guys feel that any perceptible improvements, in going from F7 - F8, to F9 or 10, are worth the additional length and bulk? (Given equal optical quality) I still remember the views through a 10" F7 at a star party many years ago. I know the long focal length comes in handy for planets, but is there any other determining factor over a comparably smooth, say F7 telescope?

This is one of my "slow" telescopes; since I masked the TDE (my first and only mirror) it works at about F7. More to the point, it was almost 30 years in the making...


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