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Astraforce Paul
Carpal Tunnel


Reged: 04/05/05
Posts: 2156
Plettstone telescopes...
      #432983 - 05/08/05 04:23 PM

These look intriguing. Quite different in appearance, based on Albert Highe's design (see latest Sky & Telescope).

What's your judgment about the design? They use a 3 truss system with a ring rather than 4 or 8 with upper cage assembly.

Will that work? It would mean no shroud... is that risky in a backyard that sometimes has to cope with neighbors' lights being on? They have no fans, though I suppose those could be added later. Given how open the scope is, is a fan even necessary?

What about the pricing? They seem steep, lots of $$, yet there's an elegance there...

Would you pay that amount--which is even higher than a Zambuto equipped Starmaster? Any other alternative scopes or alterations that could be made to the Starmaster to reduce assembly steps or lower weight?

I'd be interested in what people think about them. Also, has anyone seen one or used one? If so, maybe you can give us some first-hand reactions ...


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Tom L



Reged: 01/07/04
Posts: 31037
Loc: Sunny Oregon
Re: Plettstone telescopes... new [Re: Astraforce Paul]
      #433059 - 05/08/05 06:34 PM

I'm biased and therefore not capable of giving an honest opinion of it.

In all designs, there are tradeoffs. This design is no different. These are designed to be ultra-light weight and they therefore don't have the mass of an Obsession style scope. This is evident when you push it around. Still...this design meets my criteria andthe reason I have based the design of my Dob on it. I want the lightest scope with the biggest mirror I can comfortably move around.

As far as price...you get what you pay for!

Hopefully some of the Obsession-style guys will chime in and give you a more balanced answer.

--------------------
Tom
Tele Vue 102mm f/8.6 on an EzTouch
Vixen 80mm f/5 A80SSWT on a grab-n-go mount


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Tom TrusockAdministrator



Reged: 02/26/02
Posts: 33846
Re: Plettstone telescopes... new [Re: Tom L]
      #433136 - 05/08/05 08:15 PM

Quote:


In all designs, there are tradeoffs. This design is no different. These are designed to be ultra-light weight and they therefore don't have the mass of an Obsession style scope. This is evident when you push it around. Still...this design meets my criteria andthe reason I have based the design of my Dob on it. I want the lightest scope with the biggest mirror I can comfortably move around.





Completely agree.

I own an ultralight 8" (Starbuckets - modified highe design) and an 18" Obsession, and frankly while there are definate advantages, IMO, there are also some disadvantages to the ultralights.

I'd say the following - if you need the ultraportability and light weight - they can't be beat. If you can handle a little more mass however - that's *really* not a bad thing.

Just remember everything's a compromise - I've never found my perfect scope (although I have found a few things that come close).

--------------------
You do not need a parachute to skydive, you only need a parachute to skydive twice...


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Jarad
Postmaster


Reged: 04/28/03
Posts: 5732
Loc: Atlanta, GA
Re: Plettstone telescopes... new [Re: Tom Trusock]
      #433226 - 05/08/05 09:45 PM

I saw an 18" one of these at the Peach State Star Gaze a few months ago. Beautiful scope. It belongs to Darren Hiebert, who is on CN, so you could PM him for more info.

It's a little lighter than a Starmaster, but not really a huge amount. Also, if weight is the main issue to you, the Starmaster has the removeable mirror cell which really cuts down on the max weight you actually have to lift (although it takes up more room in the car, then). I don't think the shroud is necessary if the baffles are designed correctly, which they seem to be (didn't view in light pollution, so can't say for certain).

Michelle has a good reputation, so I would probably rank her scopes up with the other premium scopes. It can come with full GOTO as well. Other options would be Starmaster, Starstructure, T-scopes, Obsession, Sky Designs, etc. Portaball is an option if you don't need GOTO and stay at 14.5" or less. All of these cost a fair amount, as others have noted, but that's what a premium large dob costs.

Jarad

--------------------


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MMICKELS
Aluminum Knight


Reged: 01/20/04
Posts: 36050
Loc: Land of Shake and Bake
Re: Plettstone telescopes... new [Re: Jarad]
      #433454 - 05/09/05 01:09 AM

I've checked out the construction of Michelle's scopes, and can say that she does a beautiful job. Unfortunately I've never had the opprotunity to look through one.

--------------------
Mark


I'm going outside to stand, so if anyone asks I am outstanding.






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Astraforce Paul
Carpal Tunnel


Reged: 04/05/05
Posts: 2156
Re: Plettstone telescopes... new [Re: MMICKELS]
      #433608 - 05/09/05 07:55 AM

Appreciate the responses. Any more thoughts on the baffling vs. local light pollution?

Is it risky removing the mirror cell in a truss? Do I want to be taking a Zambuto mirror and its cell in and out of the mirror box? Or am I imagining a risk that's not really there?

What do you all think about the Plettstone as a choice for a 12.5" ? vs. say a 13" or 14" T-scope? or an 11" or 12.5" Starmaster ELT?


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Tom TrusockAdministrator



Reged: 02/26/02
Posts: 33846
Re: Plettstone telescopes... new [Re: Astraforce Paul]
      #433622 - 05/09/05 08:15 AM

Quote:


Any more thoughts on the baffling vs. local light pollution?





I find a shroud absolutly essential if there's local ambient light pollution.

Quote:


Is it risky removing the mirror cell in a truss?





Personally, I'm not that comfortable taking the mirror out of the box myself. The less I handle the mirror, the less chance of damaging it. It's important to note that many folks have no problems with it, and even if you worry about it, it may be a trade off you choose to make.

As per the 13 - 14" - aperture always lets you see more. T-scopes are well built and a very good value. The 12.5" plettstone would be a killer travel scope tho. You might also want to look at the starbuckets 12.5. With 6 poles, in the standard truss configuration, I suspect you will find it a more rigid structure. The three pole design does have a certain visual elegance however...

Tom T.

--------------------
You do not need a parachute to skydive, you only need a parachute to skydive twice...


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Jarad
Postmaster


Reged: 04/28/03
Posts: 5732
Loc: Atlanta, GA
Re: Plettstone telescopes... new [Re: Astraforce Paul]
      #433653 - 05/09/05 08:52 AM

Quote:

Is it risky removing the mirror cell in a truss? Do I want to be taking a Zambuto mirror and its cell in and out of the mirror box? Or am I imagining a risk that's not really there?





With the Starmaster design, I really didn't find this to be a problem. The whole cell comes out, not just the mirror, and the mirror is firmly held into the cell (even if you tip it forward). The cell has a square frame, so you can set it down on edge or on it's back with no danger to the mirror. It also comes with a transport/storage box, which keeps it safe in the car and keeps the dust off while it's in storage. It attaches to the rocker box with 4 bolts with large finger knobs, quite easy to install or remove and quite secure. I even found collimation to be very repeatable. And it has the advantage of cutting the weight of teh heaviest pice about in half (mirror plus cell will be the heaviest piece, vs. mirror plus cell plus rocker box in other scopes).

The biggest disadvantage to this setup to me was that the mirror transport box takes up another space in the car (meaning that for an 18" scope, you need room for two 30"x30" squares instead of just one). If you have a small car, or want to bring lots of family, friends, or luggage, this could be an issue. You can always just leave the mirror and cell in the scope, but make sure you have someone to help you lift the rocker box into the car (or use a ramp or something similar). Be careful lifting that part for scopes that don't have the removeable mirror, too. It's very easy to hurt your back with the lift and lean forward motion you use to put something big and heavy into the trunk.

Jarad

--------------------


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miniventures
Something Else


Reged: 09/13/03
Posts: 11259
Loc: Powell Butte, Central Oregon
Re: Plettstone telescopes... new [Re: Jarad]
      #433668 - 05/09/05 09:08 AM

I have viewed through a Plettstone telescope a number of times.The views are staggeringly beautiful and, of course, the telescope itself is elegant in design and incredibly portable as well as very functional. The scopes I've looked through are not her production models but her star party ones that she claimed have glitches and that she would never sell them.

I remember talking with Michele about a shroud and she said that it wasn't necessary at all. I'm not a technical sort of person (kind of put the key in, turn it and start the car) so I don't really remember the reasoning why. I do know that at the same star parties, I've looked through Starmassters and Obsessions that were shrouded and the Plettstone scopes held up very well against them. I have a friend who has a 12.5" Portaball and it's a great scope. I would love to do a side by side comparison with it and one of Michelle's scopes.
About all I can say is that a Plettstone scope is on my list of "have to have's somewhere down the road. I'm not sure if it's before or AFTER the TV 102 but that goes in a different forum Don't think you can go wrong with a Plettstone.

--------------------
LarryC
Volunteer
http://www.sunrivernaturecenter.org






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Tom TrusockAdministrator



Reged: 02/26/02
Posts: 33846
Re: Plettstone telescopes... new [Re: miniventures]
      #433829 - 05/09/05 11:33 AM

Quote:


I do know that at the same star parties, I've looked through Starmassters and Obsessions that were shrouded and the Plettstone scopes held up very well against them.





A shroud shouldn't be as necessary to block stray light at a star party - most of these are at dark sites to begin with. It's the neighbors garage light that bothers me.

Another benefit of a shroud (one that DOES matter at a star party) is that it blocks access to the mirror. It prevents dew/frost formation on the primary (yes, I've had this when I observed without), and the accidental dropping on something onto the mirror.

Tom T.

--------------------
You do not need a parachute to skydive, you only need a parachute to skydive twice...


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jrcrillyAdministrator
Refractor wienie no more


Reged: 04/30/03
Posts: 30716
Loc: NE Ohio
Re: Plettstone telescopes... new [Re: Tom Trusock]
      #433839 - 05/09/05 11:42 AM

Quote:

Another benefit of a shroud (one that DOES matter at a star party) is that it blocks access to the mirror. It prevents dew/frost formation on the primary (yes, I've had this when I observed without), and the accidental dropping on something onto the mirror.

Tom T.




Makes it look less like an ashtray.

--------------------
John C

Battle Cry of Reno
http://www.wadsworthobservatory.com
My Cloudy Nights gallery

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mystery EQ mount on the way


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Starman1
Vendor (EyepiecesEtc.com)


Reged: 06/24/03
Posts: 17639
Loc: Los Angeles
Re: Plettstone telescopes... new [Re: jrcrilly]
      #433850 - 05/09/05 11:56 AM

I regularly observe at a dark site, but I will state that a shroud is essential even there.
The light from the sky (there is always some) can enter the mirror box from outside the UTA. This light will scatter in the mirror box, reflect off the truss poles, and generally have the effect of light scatter in the telescope.
Ray tracing shows much of this scatter exits the scope the same way it got in, but not all.
Add to that the dew/frost issue, the passage of heat from the body into the optical path, and the risk of airborne pollen and contaminants settling on the mirror through a much larger opening, and a shroud is just, plain, necessary.

--------------------
Don Pensack
www.EyepiecesEtc.com
12.5" Teeter/Zambuto, 5" Maksutov
Sustaining Lifetime IDA member



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Cosmosphil
Pooh-Bah


Reged: 02/04/05
Posts: 1230
Loc: So. California
Re: Plettstone telescopes... new [Re: Astraforce Paul]
      #433934 - 05/09/05 01:11 PM

Paul,
As per Tom & Don, shrouding is a little more important
than you would think. Even one stray pourch light a mile away at a dark site will ruin the view in an open truss.
Just because a scope looks sexy doesn't mean its a good tool in different situations and conditions!
I have used a couple of 11" ELTs and they are wonderful scopes for minimal weight hauled around and stunning views.
You are also paying lots for the aperture due to Zambuto optics.

--------------------
Phil Agins
15" Discovery TD
10" Discovery PDHQ
5.7" Ceravolo Mak-Newt HD145
TEC 140, Stellarvue SV115T20, TeleVue-102
Vixen ED80Sf, APM-LOMO 80/600
Coronado PST, Lunt LS60THaDS60/B1200
Porta Mount, GPD2, Sphinx SXD


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Astraforce Paul
Carpal Tunnel


Reged: 04/05/05
Posts: 2156
Re: Plettstone telescopes... new [Re: Cosmosphil]
      #435115 - 05/10/05 11:45 AM

Great feedback! The Plettstone site, IIRC, says that a shroud isn't needed because of how well baffled the scope is. But perhaps that doesn't work as well if a neighbor's deck light is on!

Maybe the best baffling in the world isn't sufficient to block ALL stray light...

OTOH, IIRC, the site also suggests that shrouds can produce tube currents.

Everything in life really is a compromise, or filled with trade-offs, isn't it?


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Jeff Morgan
Post Laureate


Reged: 09/28/03
Posts: 4018
Loc: Prescott, AZ
Re: Plettstone telescopes... new [Re: Astraforce Paul]
      #435787 - 05/10/05 10:59 PM

Quote:

Great feedback! The Plettstone site, IIRC, says that a shroud isn't needed because of how well baffled the scope is. But perhaps that doesn't work as well if a neighbor's deck light is on!

Maybe the best baffling in the world isn't sufficient to block ALL stray light...

OTOH, IIRC, the site also suggests that shrouds can produce tube currents.

Everything in life really is a compromise, or filled with trade-offs, isn't it?




Yes, it is all a compromise. Baffling, like coma or chromatic abberation, seems to be in the eye of the beholder.

All of the minimalist designs prioritize weight. Period. They essentially rely on a black background behind the secondary mirror to mask vieling glare. At best (and please correct me if I am wrong) this "flat black" surface will be around 4% reflective. However, if the light hitting that surface has first hit another similar surface the reflectance drops to about 1/16th of 1%. Even if my initial 4% is wrong, the second surface makes a huge difference. Take your pick. Take away the nebular and line filters and I seriously doubt that any minimalist design can show more contrast than a long focus traditionally baffled system. My own experience is that the latter don't even need filters.

They are more portable, they are lighter, they may have more true field by virtue of less focal length, and they may be able to bring more aperture to the table. But for equal apertures, my own limited experience says the minimalist designs don't compete to a "more traditional" system.

--------------------
Jeff Morgan
Prescott, AZ
Wile E. Coyote School of Telescope Making


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