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Equipment Discussions >> Reflectors

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BigC
Carpal Tunnel
*****

Reged: 09/29/10

Loc: SE Indiana
Re: Sky Watcher 18" prototype new [Re: skyward_eyes]
      #6205627 - 11/20/13 12:26 PM

I WANT one!

Probably won't be able to afford it though.


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Galicapernistein
super member


Reged: 09/24/07

Loc: Detroit Michigan
Re: Sky Watcher 18" prototype new [Re: skyward_eyes]
      #6205812 - 11/20/13 02:09 PM

Quote:

The 150 pound weight came from factory. This scope is entirely made of metal so the weight might be a bit higher as the Obsession uses wood. Once the scope arrives from the show I will be able to weigh it.

The scope is a 9 point flotation cell.




As long as the individual components arent too heavy I could live with a 150 pound 18" scope. I would much rather have a heavy, sturdy scope than a flimsy light one.


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skyward_eyes
Vendor - Sky-Watcher USA
*****

Reged: 12/12/06

Loc: California
Re: Sky Watcher 18" prototype new [Re: Galicapernistein]
      #6205826 - 11/20/13 02:18 PM

Yes, this is fully put together of course. I am not sure what the heaviest component will be at this time but it should be manageable. I am a dob user myself and wont let this thing out until its something I would want to buy.

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drago
sage


Reged: 01/11/08

Loc: Latvia
Re: Sky Watcher 18" prototype new [Re: BigC]
      #6206867 - 11/21/13 02:20 AM

Quote:

I WANT one!

Probably won't be able to afford it though.




why, for example, an "hubble optics" 18" f/4.0 Premium Ultra Light Dobsonian System not fit for you?
in what matters, you think, skywatcher variant will be better?


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Manousos
member


Reged: 06/11/08

Loc: Crete-Hellas
Re: Sky Watcher 18" prototype new [Re: drago]
      #6208819 - 11/22/13 06:22 AM

Hi, this is very promising for a mass production company such as Skywather. However, IMHO this prototype needs improvements considering weight as well as design improvements. Truss dobsonians and particular this type of minimalistic design should be light and at the same time rigit. Rigidity can be acheived with lighter design and implementation. There are much lighter and more rigit scopes in the market.

I fully agree that the primary need is to consider rigidity but also weight reduction is mandatory. I'm amateur constructor of three truss dobsonian scopes. The first scope I was built was very heavy, the seconds was more lighter and the third was even lighter than the olders. Rigidity was the same on the heavier and on the lighter version of the scopes (for the same diameter and focal ratio).

I think that if the above issues will be addressed and with a logical compromise on the final cost, the telescope will be more competitive regardind the available models on the market today.


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akulapanam
super member


Reged: 08/27/12

Re: Sky Watcher 18" prototype new [Re: Manousos]
      #6228271 - 12/02/13 12:50 AM

As someone that is looking at the hubble optics 18" f4.5 right now this scope isn't very interesting at $5k and 150 lbs. The Hubble 18" is 72 pounds and $3k and for $5k you can get the full goto and every accessory. Now you add goto and get the weight to 100lbs then this guy gets interesting.

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Fireball
professor emeritus


Reged: 03/24/06

Re: Sky Watcher 18" prototype new [Re: akulapanam]
      #6228379 - 12/02/13 04:08 AM

Quote:

As someone that is looking at the hubble optics 18" f4.5 right now this scope isn't very interesting at $5k and 150 lbs. The Hubble 18" is 72 pounds and $3k and for $5k you can get the full goto and every accessory. Now you add goto and get the weight to 100lbs then this guy gets interesting.



That's right, even the Hubble UL20" is lighter and the price for the f4.2 is still less than 5k - worth to think about!


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Astrojensen
Post Laureate
*****

Reged: 10/05/08

Loc: Bornholm, Denmark
Re: Sky Watcher 18" prototype new [Re: Fireball]
      #6228424 - 12/02/13 05:55 AM

I wasn't even aware the Hubble Optics scopes were that inexpensive. The 16" UL is CHEAPER than a 16" Meade Lightbridge here in Europe, even with shipping! (but without taking customs into account!) Even with customs and VATT added, the 16" HO UL is only modestly more expensive than the 16" Meade LB, by about 15% - 20%. The Meade LB outweighs the HO UL by more than 100%...

That is ridiculous! I am now SERIOUSLY considering a 16" f/5 HO UL.


Clear skies!
Thomas, Denmark


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radicell2
member


Reged: 01/15/10

Re: Sky Watcher 18" prototype new [Re: Roy McCoy]
      #6237072 - 12/06/13 10:53 AM

Quote:

Quote:

But my question concerns the cylinders between the upper and lower thin solid sections: they are filled with air which expands and contracts with temperature. Does that internal pressure change affect the surface figure of the mirror above the cylinders? The mirror could be perfect at +20C. Does it appear dimpled at -20C?




Don,

I noticed that there were small Vs in the bottom of the cylinders which I assume were needed during the fusing process. These openings should help mitigate the temperature differential a little.


Regards,




Bit odd the thicker baseplate versus the thinner faceplate.If you wont to reduce the mass/heat transfer through the entire blank putting the heavier/thicker glass on the bottom is the wrong way to do things.Also I'd be very concerned over the use of different thickness plates from different melt batches,plus the different melt batches of the tubes from a different manufacturer,plus different melt batches within the numerous tubes.Even a slight Cof.of Expansion difference in the glass melt batches will cause a slight distortion in various areas of the glass as it expands/contracts.Don't expect anything better than 1/2 wave on the surface from this type.

Ric

Edited by radicell2 (12/07/13 10:17 AM)


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Zoomit
sage


Reged: 12/04/06

Loc: Tehachapi, CA
Re: Sky Watcher 18" prototype new [Re: Starman1]
      #6237451 - 12/06/13 01:52 PM

Quote:

A few things I noticed:

//cut//

--curved focuser board. I don't know why no one else thought of this. It really improves the rigidity of the focuser mount.

//cut//





Agreed Don. Hopefully the upper truss, focuser board, and focuser can handle the off-axis weight of a binoviewer and a set of eyepieces without bending out of collimation. I suspect that that's a design case that some dob manufacturers may not adequately consider.

I don't care how heavy or light it is if it can't stay collimated.


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hbanich
Pooh-Bah
*****

Reged: 06/17/05

Loc: Portland, Oregon
Re: Sky Watcher 18" prototype new [Re: Zoomit]
      #6237692 - 12/06/13 04:16 PM

Quote:

Quote:

A few things I noticed:

//cut//

--curved focuser board. I don't know why no one else thought of this. It really improves the rigidity of the focuser mount.

//cut//





Agreed Don. Hopefully the upper truss, focuser board, and focuser can handle the off-axis weight of a binoviewer and a set of eyepieces without bending out of collimation. I suspect that that's a design case that some dob manufacturers may not adequately consider.

I don't care how heavy or light it is if it can't stay collimated.




Obsession has used curved focuser boards since 1989, so this isn't new, but it is difficult to do properly. Curving a flat piece of wood needs moisture and pressure, and if you observe in a moist climate the curved board can start to warp.


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Starman1
Vendor (EyepiecesEtc.com)
*****

Reged: 06/24/03

Loc: Los Angeles
Re: Sky Watcher 18" prototype new [Re: hbanich]
      #6237712 - 12/06/13 04:26 PM

Quote:

Quote:

Quote:

A few things I noticed:

//cut//

--curved focuser board. I don't know why no one else thought of this. It really improves the rigidity of the focuser mount.

//cut//





Agreed Don. Hopefully the upper truss, focuser board, and focuser can handle the off-axis weight of a binoviewer and a set of eyepieces without bending out of collimation. I suspect that that's a design case that some dob manufacturers may not adequately consider.

I don't care how heavy or light it is if it can't stay collimated.




Obsession has used curved focuser boards since 1989, so this isn't new, but it is difficult to do properly. Curving a flat piece of wood needs moisture and pressure, and if you observe in a moist climate the curved board can start to warp.



The SW appeared to be aluminum plate, hollowed out and with a criss-cross web pattern on the back. There may be flex at the upper ring, but that plate isn't going to budge. Or warp.


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Zoomit
sage


Reged: 12/04/06

Loc: Tehachapi, CA
Re: Sky Watcher 18" prototype new [Re: Starman1]
      #6237727 - 12/06/13 04:38 PM

Quote:

Quote:

Quote:

Quote:

A few things I noticed:

//cut//

--curved focuser board. I don't know why no one else thought of this. It really improves the rigidity of the focuser mount.

//cut//





Agreed Don. Hopefully the upper truss, focuser board, and focuser can handle the off-axis weight of a binoviewer and a set of eyepieces without bending out of collimation. I suspect that that's a design case that some dob manufacturers may not adequately consider.

I don't care how heavy or light it is if it can't stay collimated.




Obsession has used curved focuser boards since 1989, so this isn't new, but it is difficult to do properly. Curving a flat piece of wood needs moisture and pressure, and if you observe in a moist climate the curved board can start to warp.



The SW appeared to be aluminum plate, hollowed out and with a criss-cross web pattern on the back. There may be flex at the upper ring, but that plate isn't going to budge. Or warp.




Sounds robust (and done right). If the focuser is equally robust, then I'd only be concerned about the upper ring and how rigidly the focuser plate is attached to it. From the pictures, it looks like the focuser board is cantilevered downward from the ring. That's not a promising configuration to keep a binoviewer from deforming the upper ring when the scope it pointed up and the ring is under a torsional load.


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Solar Ken
professor emeritus
*****

Reged: 02/07/06

Loc: Oregon
Re: Sky Watcher 18" prototype new [Re: bob irvin]
      #6237830 - 12/06/13 05:51 PM

Quote:

It would be nice to have an alternative to the Obsession.

bob




Why do you say that? Just curious...


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AcTrust
sage


Reged: 08/11/13

Re: Sky Watcher 18" prototype new [Re: Solar Ken]
      #6241198 - 12/08/13 05:20 PM

I am very happy to see this from Skywatcher. It means the company is doing well and is dynamic. Trying to become better through challenge and change. I am a little worried about buying a first gen model as with any product but I agree and think it's nice to see a scope aimed directly at potential Obsession buyers. Competitive products usually means a better product for a cheaper price.

Either way it's pretty cool to see! Good stuff Skywatcher just don't use those silly focusers with the adapters for 2" EPs lol.


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jonstarrysky
professor emeritus


Reged: 01/03/09

Loc: England, U.K.
Re: Sky Watcher 18" prototype new [Re: AcTrust]
      #6242510 - 12/09/13 12:00 PM

Looks a bit like what Orion did a few years back. Difference is Orion seem to have made a school boy error (units mixed up ?) and bizarrely ended up with a 50" dob, like that is the logical step up from 14". Looks like SW are closer to the mark with this one.

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Pinbout
Postmaster
*****

Reged: 02/22/10

Loc: nj
Re: Sky Watcher 18" prototype new [Re: jonstarrysky]
      #6243349 - 12/09/13 06:55 PM

Orions 14 was a hubble optics scope
Orions 50monster was a norman fullum scope.


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skyward_eyes
Vendor - Sky-Watcher USA
*****

Reged: 12/12/06

Loc: California
Re: Sky Watcher 18" prototype new [Re: Pinbout]
      #6260584 - 12/18/13 05:37 PM

I know everyone was going back and forth about the weight, so reweighed the prototype. Now this is without a finder, eyepiece and counter weights.

Telescope weight with optics is 113 pounds fully assembled.


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gene 4181
Pooh-Bah


Reged: 11/12/13

Loc: n.e. ohio
Re: Sky Watcher 18" prototype new [Re: skyward_eyes]
      #6260633 - 12/18/13 05:55 PM

i 'm sorry about going off topic, but it would be nice to see all the other skywatcher scopes available here in the states, eg., maks, mak-newts and eq . mounted newts. ?

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Galicapernistein
super member


Reged: 09/24/07

Loc: Detroit Michigan
Re: Sky Watcher 18" prototype new [Re: gene 4181]
      #6262141 - 12/19/13 03:16 PM

Mass produced dobs in the 8-16" range are (usually) at least 50% cheaper than the premium brands. That assumes a mirror not made to the stringent standards of higher priced scopes, but good enough for many. The question is whether an 18" scope can achieve the price savings of being mass produced, if there is such a thing as an 18" scope that can be mass produced. I doubt that the new Skywatcher can be sold for 50% less than a premium brand simply because it doesn't seem that the sales numbers would allow that, although I could be wrong. If the price is too high many people may opt to pay the difference to get a higher end scope. Of course, that's assuming the new Skywatcher is going to be sold as a cheaper alternative to the premium brands. It may turn out to be a competitor for the premium ultra compact models. Whatever kind of scope it turns out to be, I'm sure it's going to generate alot of interest.

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