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Re: Parallax Newtonian telescopes


Oct 3, 2009

 


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#44130 Oct 3, 2009

Hi everyone does anyone on this group have a Parallax Newt. telescope if so I would be very interested in what they think of it , they seem to be very well made if a bit pricey. I live in the UK and there does not seem to be any over here so just would like to know what is the view of them in the US. THANKS everyone.



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#44141 Oct 3, 2009

Parallax has a good reputation and so does Parks Optical. There is a rivalry between the two firms in that Parallax, if memory serves, believes fiberglass is an optimal tube, whereas Parks goes for aluminum.



The details are obscure to me. (I use an SCT, and it is aluminum)



I have read an occasional good thing about Parallax mounts and when I was in the market for a Titan/AP900 class mount I considered the Parallax for a while. However, the problem is that it has a tiny user base and therefore a tiny aftermarket and therefore you're really dependent on your own resources or the entrepreneur in charge. I think there were maybe 25 or 40 members on the Parallax Yahoo group when I looked into it. Losmandy has 3400. AP has over 2,000, and so on. Parallax uses the Gemini system last I checked so you'd have that much in common with the larger user base.



Another option is just to look into optical tubes in your country, see who makes good ones, and see if you can get one. Once you have, it is fairly easy to mount a focuser and a mirror cell: you can buy the mirror from Swayze or Torus or Royce, etc.



Presumably you are into German equatorial mountings if you are on this group. The exact dimension Newt that you could put on a G11 would depend on focal length, but 8 to 12 inches would top out I think depending on different design factors.



regards,

Greg N

--- In Losmandy_users@yahoogroups.com, "patconlon" ploughc@...> wrote:

>

> Hi everyone does anyone on this group have a Parallax Newt. telescope if so I would be very interested in what they think of it , they seem to be very well made if a bit pricey. I live in the UK and there does not seem to be any over here so just would like to know what is the view of them in the US. THANKS everyone.

>



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#44143 Oct 3, 2009

gnowellsct wrote: > Parallax has a good reputation and so does Parks Optical. There is a rivalry between the two firms in that Parallax, if memory serves, believes fiberglass is an optimal tube, whereas Parks goes for aluminum.

>

Parks is famous for the good looking but heavy fiberglass tube.



Bud



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#44144 Oct 3, 2009

So I had it backwards? Thanks for the correction. Greg N

--- In Losmandy_users@yahoogroups.com, William Hamblen wrhamblen@...> wrote:

>

> gnowellsct wrote:

> > Parallax has a good reputation and so does Parks Optical. There is a rivalry between the two firms in that Parallax, if memory serves, believes fiberglass is an optimal tube, whereas Parks goes for aluminum.

> >

> Parks is famous for the good looking but heavy fiberglass tube.

>

> Bud



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#44145 Oct 3, 2009

Parks supplied fiberglass tubes for Cave for many years up until Cave's last years, when Cave switched to Meade "Fiberlite" tubes. Parks, which had fallen under Scope City ownership, acquired Cave's equipment and began producing essentially Cave scopes. I don't know who made/makes Parks mirrors. I recently found out that Meade's highly-regarded "Research Series" Newtonians of the late 1970s used optics made by Coulter. Who woulda thunk it?



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#44147 Oct 4, 2009

Parallex tubes have always been aluminum, and Joe Nastaci-the owner- is one source for high quality large scope tubes.As for the mounts, havn't looked lately, but the drives used to be Astrophysics.-------------- Original message from "gnowellsct" tim71pos@...>: --------------



So I had it backwards? Thanks for the correction. Greg N

--- In Losmandy_users@yahoogroups.com, William Hamblen wrhamblen@...> wrote:

>

> gnowellsct wrote:

> > Parallax has a good reputation and so does Parks Optical. There is a rivalry between the two firms in that Parallax, if memory serves, believes fiberglass is an optimal tube, whereas Parks goes for aluminum.

> >

> Parks is famous for the good looking but heavy fiberglass tube.

>

> Bud











[Non-text portions of this message have been removed]



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#44148 Oct 4, 2009

Well I guess we're all writing from memory because we're too lazy to visit parallax home page and see what they're up to! But I would visit the Parks Optical site too were I buying.



I don't know what to make of the fiberglass vs aluminum debate in Newts. On SCTs I have an opinion about cargon fiber which solves one problem (thermal contraction which affects focus in imaging) at the expense of another one (slows down cooling).



We have a large group so there will be some Newt owners here. But the trend of the last 18 years is pretty clear: Newts do not often get used on GEMs these days, in the high end markets (there are lots of chintzy 4 inch refractors sold on chintzy GEMs). The Newts go into Dob configuration and the GEMs carry refractors and various compound designs, most often but not always SCTs. This makes sense given the fact that Newts offer large apertures cheap and the larger they are the harder it is to make them work on a GEM. One can tell the trend just by monitoring astromart: there are very few ATS piers and other secondary equipment designed to keep GEMs low for Newtonian use. And I mean *very* few.



It's not just the question of using a ladder to get at the eyepiece, which is a big obstacle for many of us. As pointing systems and go-to have increased in popularity, the problem of the Newt on the Gem is pretty tough: the eyepiece has to be rotated for the viewer, but the larger the Newt, the more this rotation affects the pointing of the optical axis, which messes up the pointing model. So either you rotate the tube back to a specific slewing position or you use a smaller Newt which is easier to rotate and will offer a larger field to accommodate the pointing error. And by the time we start talking smaller apertures people often wander off into refractors and compound designs which offer less sail area and less moment arm per inch of aperture delivered, thereby getting more stability value out of the GEM per inch of aperture carried. (By contrast go-to systems in alt-az maintain a fixed position for the eyepiece so they can achieve high pointing accuracy, the optical axis is modeled into the pointing and doesn't change)



regards

Greg N

--- In Losmandy_users@yahoogroups.com, drgenovese@... wrote:

>

> Parallex tubes have always been aluminum, and Joe Nastaci-the owner- is one source for high quality large scope tubes.As for the mounts, havn't looked lately, but the drives used to be Astrophysics.-------------- Original message from "gnowellsct" tim71pos@...>: --------------

>

> So I had it backwards? Thanks for the correction. Greg N

>

> --- In Losmandy_users@yahoogroups.com, William Hamblen wrhamblen@> wrote:

> >

> > gnowellsct wrote:

> > > Parallax has a good reputation and so does Parks Optical. There is a rivalry between the two firms in that Parallax, if memory serves, believes fiberglass is an optimal tube, whereas Parks goes for aluminum.

> > >

> > Parks is famous for the good looking but heavy fiberglass tube.

> >

> > Bud

>

>

>

>

>

> [Non-text portions of this message have been removed]

>







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#44149 Oct 4, 2009

www.parallaxinstruments.com/mount.htm



They have indeed moved from Gemini to AP go-to systems in the past few years. They are still offering Losmandy stepper systems for non-go-to applications.



Greg N

--- In Losmandy_users@yahoogroups.com, drgenovese@... wrote:

>

> Parallex tubes have always been aluminum, and Joe Nastaci-the owner- is one source for high quality large scope tubes.As for the mounts, havn't looked lately, but the drives used to be Astrophysics.-------------- Original message from "gnowellsct" tim71pos@...>: --------------

>

> So I had it backwards? Thanks for the correction. Greg N

>

> --- In Losmandy_users@yahoogroups.com, William Hamblen wrhamblen@> wrote:

> >

> > gnowellsct wrote:

> > > Parallax has a good reputation and so does Parks Optical. There is a rivalry between the two firms in that Parallax, if memory serves, believes fiberglass is an optimal tube, whereas Parks goes for aluminum.

> > >

> > Parks is famous for the good looking but heavy fiberglass tube.

> >

> > Bud

>

>

>

>

>

> [Non-text portions of this message have been removed]

>



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#44150 Oct 4, 2009

Here's Parks OTAs:



www.parksoptical.com/index2.php?cPath=21_111&cat=Optical+Tube+Assemblies>



Greg N --- In Losmandy_users@yahoogroups.com, "gnowellsct" tim71pos@...> wrote:

>

> www.parallaxinstruments.com/mount.htm

>

> They have indeed moved from Gemini to AP go-to systems in the past few years. They are still offering Losmandy stepper systems for non-go-to applications.

>

> Greg N

>

> --- In Losmandy_users@yahoogroups.com, drgenovese@ wrote:

> >

> > Parallex tubes have always been aluminum, and Joe Nastaci-the owner- is one source for high quality large scope tubes.As for the mounts, havn't looked lately, but the drives used to be Astrophysics.-------------- Original message from "gnowellsct" tim71pos@>: --------------

> >

> > So I had it backwards? Thanks for the correction. Greg N

> >

> > --- In Losmandy_users@yahoogroups.com, William Hamblen wrhamblen@> wrote:

> > >

> > > gnowellsct wrote:

> > > > Parallax has a good reputation and so does Parks Optical. There is a rivalry between the two firms in that Parallax, if memory serves, believes fiberglass is an optimal tube, whereas Parks goes for aluminum.

> > > >

> > > Parks is famous for the good looking but heavy fiberglass tube.

> > >

> > > Bud

> >

> >

> >

> >

> >

> > [Non-text portions of this message have been removed]

> >

>



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