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12.5" Portaball/Zambuto or 10" Normand Fullum

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#1 Erik Bakker

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Posted 06 April 2011 - 06:13 AM

Which would you prefer for observing around the backyard and occasional transportation to a dark site: a 12.5" f/5 Portaball with Zambuto optics, or a Normand Fullum 10" f/4.8 with Fullum optics? Price is roughly the same.
The dob will be used as a complementary scope to my Tak FS102.

Thanks for any experiences with scopes and/or mirror/image quality.

CS,

Erik

#2 AlienRatDog

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Posted 06 April 2011 - 06:51 AM

I would go with the Portaball...2.5 more inches!

#3 Jon Isaacs

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Posted 06 April 2011 - 07:06 AM

Which would you prefer for observing around the backyard and occasional transportation to a dark site: a 12.5" f/5 Portaball with Zambuto optics, or a Normand Fullum 10" f/4.8 with Fullum optics? Price is roughly the same.
The dob will be used as a complementary scope to my Tak FS102.

Thanks for any experiences with scopes and/or mirror/image quality.

CS,

Erik


I don't see how you can go wrong with a Portaball with Zambuto Optics. And 12.5 inch is a nice size, you can view seated all night long and while it's capabilities are not a big step up from a 10 inch, a 12.5 inch is a more capable instrument.

Jon

#4 Jarad

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Posted 06 April 2011 - 08:45 AM

Obviously I chose a Portaball. For visual use, they really are very nice scopes - the ergonomics of movement and being able to rotate the focuser to any angle are very nice.

The only reason I would consider a non-Portaball of equal size is if you want GOTO capability (can't do that easily for the P-ball). I do have tracking via a platform (which I highly recommend you get).

Jarad

#5 Scopyfrank

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Posted 06 April 2011 - 09:34 AM

Never tried one of these, so just a gut feeling:
Portaball with Zambuto inside: not to say that the optics are of better quality, but it just seems more portable: Fullums seem to me to be so beautiful pieces of wood work and optical art that I would be very sad if damaged by transport here and there.
In case you'd be interested in a 14.5" Portaball:

2nd hand portaball 14.5 inch

Good luck.

#6 dvb

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Posted 06 April 2011 - 11:29 AM

Normand Fullum makes excellent optics - I doubt you would notice a difference between a Zambuto and a Fullum mirror in use.

I also doubt you'll notice much difference in aperture.

It comes down to convenience and manageability - which one are you more likely to carry outside and set-up? Which one is easier to to point and track with?

The smaller size might be easier to manage, but might not, depending on the tube and mount designs.

#7 BluewaterObserva

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Posted 06 April 2011 - 11:38 AM

I've used a Portaball a couple of times. To cool for school as far as I am concerned. The portaball.

#8 Doug Reilly

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Posted 06 April 2011 - 11:44 AM

You picked the two most unique looking scopes on the market today, except maybe with the teleport in between them. Totally different aesthetics. Like Nasa clean vs. Steampunk Fantasy. I'm a graphic artist type so the Portaball is far more appealing than the artsy Fullum.

Of course, we shouldn't really base our decisions on looks. I'd go with the larger aperture scope. That is, if the motions on a scope like the portaball are for you. I also tend to prefer having distinct alt and az motions on a non-eq scope. But that's me.

#9 Maverick199

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Posted 06 April 2011 - 12:00 PM

One of our members, GeneT has a 12.5" Portaball and as his signature suggests, a "happy owner" at that. I am sure his opinion would be positive, i.e., go with Portaball.

#10 Ken....

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Posted 06 April 2011 - 12:33 PM

If this is a scope you're going to transport frequently, and the Fullum you're considering is one of his pieces of art, then the better choice might be the one that'll stand up better to all the bumps and scrapes that'll likely accrue over the years of transporting it.

#11 mark cowan

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Posted 06 April 2011 - 02:22 PM

Like Nasa clean vs. Steampunk Fantasy.


or 2001 a space odyssey vs avatar :lol:

Best,
Mark

#12 Pinbout

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Posted 06 April 2011 - 05:39 PM

or 2001 a space odyssey vs avatar



I was thinking more like ... vs. the Hobbit. :grin:

#13 Bob S.

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Posted 06 April 2011 - 06:17 PM

Normand Fullum makes excellent optics - I doubt you would notice a difference between a Zambuto and a Fullum mirror in use.

I also doubt you'll notice much difference in aperture.


In terms of contrast, you may notice a difference as Zambuto really attends to physical issues that affect contrast. In terms of not noticing the difference between 10" and 12.5" of aperture, it is absured to say that you will not notice a difference unless you are a newbie. I happen to have owned a 10" Zambuto/Teleport and a 12.5" Stevens/Portaball and the images/performances were not equal in ANY way. Bob

#14 Jarad

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Posted 06 April 2011 - 07:35 PM

Normand has a very good reputation as a mirror maker, so I will assume that his 10" will be close enough to Zambuto quality that both scopes will give excellent views.

To me, the issues are these:
1 - Weight. Normand's scopes use a lot of wood, and are generally solid tube in that size. I suspect his 10" weighs more than the 12.5" P-ball (but I don't have numbers to back that).
2 - Transport size. The P-ball essentially collapses down to the sphere plus the trusses in a tube. A solid tube plus a wooden base take up a lot more room in the car.
3 - Aperture. Assuming equal quality, aperture wins.
4 - Ergonomics. As I said before, the rotatable ball means you always use the most comfortable viewing angle.
5 - Aesthetics. Normand's scopes aren't just for looking through, they are works of art for looking at. If you want that, get it. They are certainly gorgeous scopes.

Jarad

#15 klim

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Posted 06 April 2011 - 07:38 PM

I currently own a 10" Portaball and it is by far the easiest telescope to use. Moves in any direction. Dobson's Hole doesn't exist. You can observe from either side. Collimation stays put all night. Impossible to go wrong with a Zambuto mirror.

However, Markus Ludes of APM bought a Fullum scope because he said the optics are superb. Possible better dew control on the Fullum scope as the secondary sits lower in the tube than my Portaball configuration.

For aesthetics I'd choose the Fullum but for function I'd take the Portaball.

Mark

#16 Jon Isaacs

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Posted 06 April 2011 - 09:11 PM

I also doubt you'll notice much difference in aperture.



I have both a 10 inch and a 12.5 inch... the difference is not overwhelming but it is significant and if one hunting down faint galaxies, the 56% increase in light grasp is definitely useful. It's like going from an 80mm to a 100mm refractor, it is there to be seen.

Jon

#17 dvb

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Posted 06 April 2011 - 09:31 PM

Normand Fullum makes excellent optics - I doubt you would notice a difference between a Zambuto and a Fullum mirror in use.

I also doubt you'll notice much difference in aperture.


In terms of contrast, you may notice a difference as Zambuto really attends to physical issues that affect contrast. In terms of not noticing the difference between 10" and 12.5" of aperture, it is absured to say that you will not notice a difference unless you are a newbie. I happen to have owned a 10" Zambuto/Teleport and a 12.5" Stevens/Portaball and the images/performances were not equal in ANY way. Bob


Thank you for sharing your particular experience, Bob.

You may want to play with the chart at this link:

http://www.cruxis.co...ngmagnitude.htm

Using the stock values in that chart, a 10" would have a limiting magnitude of 15.1, a 12" of 15.4. You might get a different spread by plugging in different values.

Please note, I did not say there would not be any difference, but that would there would be not much difference. Is 0.3 magnitude more than "not much"? I suppose it could be to some. YMMV.

#18 GeneT

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Posted 06 April 2011 - 10:17 PM

Over the past few years I have owned a 20 inch Obsession, an 18 inch Obsession Ultra Compact, and a 12.5 inch Portaball. I sold both Obsessions (both great telescopes) and kept the Portaball. The Portaball is as easy to transport and set up as an 8 inch SCT. All of the elements, except the truss poles, fit inside the sphere, so you only have to grab one telescope element when setting out to view. How do you grab onto your telescope? With a Portaball, the handles are on top of the sphere, very near your hands when dropped down your side. So, it is very easy to pick up the telescope, and walk it with your knees to the vehicle. I put the telescope in the front seat of my auto, and secure it with the seat belt. It would fit in a back seat also. The truss poles fit in a small tube. I now own a Honda CRV. However, back when I owned a Civic, I could haul the telescope, eyepieces, other accessories--and three other people to the viewing site. The telescope is easy and fun to use. I do enjoy my tracking platform. It is nice to be able to view at high powers with no drift. I have owned and used my Portaball for more than 16 years--with absolutely no problems. When not in use, I store the telescope and Platform on my side of the closet. I moved out a two drawer file cabinet from the closet to the garage, and put the telescope it its place. I believe storing a telescope inside the house avoids a host of problems.

#19 Scopyfrank

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Posted 07 April 2011 - 03:51 AM

... It's like going from an 80mm to a 100mm refractor, it is there to be seen.
...


:) here I can add my grain of pepper to the discussion: that IS substantial.

#20 Bob S.

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Posted 07 April 2011 - 06:11 AM

DVB, The numbers that the Cruxis calculator present do not necessarily correlate with what the human system perceives. I have not found that these calculators are able to express values that translate into empirical experiences very well. Having owned many premium-mirrored scopes in sizes fairly close to each other and used on the same night under the same conditions continually reinforces the fact that larger aperture will always show more information. There are of course a lot of variables such as seeing, tranparency, light pollution, etc. that can minimize the apparent effects but in dark skies, larger aperture of equal quality systems will provide better views to the experienced astronomer.

#21 bartine

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Posted 07 April 2011 - 09:09 AM

I had and loved a 12.5" Portaball. Movement is incredible. the setup is very lightweight and easy to move.

Mechanically, the Portaball was one of the best built scopes I have ever used. The fit and finish was incredible.

The only "gotcha" on the design is balance - overly light or too heavy eyepieces can cause issues. This was very rare for me, and really only happened when I had too much wax on the sphere. I did have issues when I tried to use both a 50mm right angle finder and a 20mm Nagler at the same time - it was just too much an it over-balanced the scope.

So - beautifully engineered, but you need to keep it fairly stock...

#22 Lamb0

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Posted 08 April 2011 - 11:46 PM

Yup, I'd have to go with the Normand Fullum so I could use my preferred optical combinations. The glassmongery and accessories must be appropriate for the Portaball's balance. However, many would have no problem with their chosen eyepieces and the Portaball's extra aperture is nice. YMWV

I don't consider the choice of opticians to be an issue - both are excellent.

#23 ybor

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Posted 09 April 2011 - 10:39 AM

Which scope do you think would have a better resale value in the future ?

#24 Scopyfrank

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Posted 09 April 2011 - 05:07 PM

I'd expect the NFs to be more special and rare amateur focused scopes, the ones who appreciate such design, wood work etc.
Portaballs are more functional and hence, may attract more 2nd hand amateurs.
So what will be the best retail value? The value of a scope for less amateurs but who would really pay the price for it or the value of a scope that targets more common amateurs with, may be, less retail value but better chances for a quicker deal?
I think it can't be reduced to the sole optical qualities I expect very close one to the other.

#25 GeneT

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Posted 09 April 2011 - 08:13 PM

The only "gotcha" on the design is balance - overly light or too heavy eyepieces can cause issues. This was very rare for me, and really only happened when I had too much wax on the sphere. I did have issues when I tried to use both a 50mm right angle finder and a 20mm Nagler at the same time - it was just too much an it over-balanced the scope.


I have a first generation Portaball. When I bought it, Peter Smitka asked what eyepieces I would be using, and so balanced the telescope. My sphere is made of aluminum and the new ones are made of fiber glass. That will probably help with the balance issues, which are caused by slipperiness. Also, the new telescopes come with a new base which offer more stiction than the older ones. I cut down on the wax to increase stiction which solved my problem. To use a Paracorr, since it was not balanced with one in mind, I found a three pound ankle weight which is flattened and can lay around the edge of the bottom of the sphere. This was a cheap and easy balance fix. The weights can be cut into three one pounders if less weight is needed. I have solved the balance issue with heavy eyepieces such as a 31mm Nagler and a Paracorr. I am now awaiting shortened truss poles to get some additional in focus. If my in focus issues are solved, then I have solved both balance and focus issues with my Portaball. What I have described above is not unusual for Dob owners to have to work through. If you buy a new Portaball, tell Mag 1 what your eyepiece combinations and Paracorr or no Paracorr, and the telescope will be built to accommodate your preferences.






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