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Older Portaballs?

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#1 mkothe

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Posted 09 July 2013 - 10:45 PM

Hi,

I am still searching for my next telescope to upgrade from my 8" dob and have now arrived at considering a 12.5" Portaball. I have always been fascinated by what I read about these (and the Teleports) in terms of ease of use and mechanical and optical quality, and I think I could afford one at the lower end of the spectrum of what I have seen advertised. My question is what kind of compromises/issues would I have to contend with if I get a lower priced (and therefore possibly older) Portaball? I think I have read that older models had less reliable electronics or wiring. What other improvements have been made over the years, and when? How can I tell how old a given Portaball is from the description?

Thanks,
Michael

#2 peleuba

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Posted 10 July 2013 - 09:11 AM

As you've alluded to, the biggest issue you'll come up against is the fragile nature of the electrical interfaces and the wiring. I've owned a number of Portaballs through the years, have become a friend of the firm so-to-speak, and have rewired several of them. Its a real pain to do.

The improvements have come in three main areas:

1. more robust electrical package
2. addition of a CNC mirror cell
3. the now standard use of a FeatherTouch focuser.

The appearance of the 12.5 Portaballs have changed very little until recently, so you cannot go by appearances alone. Best thing to do is to look at the date on the primary mirror. Though, if you do come across one with a spun aluminum ball instead of the newer style fiberglass sphere, its a very early model.

The Mag1 story is a good one. The company once wholly owned and operated by Peter Smitka was days away from ceasing to exist. Dave Jukem, who was the machinist Peter employed to design and manufacture most of the parts on the Portaball (including the spehere) acquired the assests (actually at that time it was mostly liabilities) from Peter and made good on all outstanding orders and offered refunds to anyone who was waiting on a telescope.

Fast-forward to today and the Portaballs now are mostly CNC machined with a bullet proof wiring scheme and are potent observing packages representing the finest mirror-based telescopes in their respective aperture class.

Mag1 elected not to attend NEAF this year but unveiled Portaball-18 there in 2012.

My 8" Portaball is my most used telescope, by far.

#3 GeneT

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Posted 10 July 2013 - 03:48 PM

I have one of the older Portaballs, called the first generation Portaballs. The sphere was made of aluminum. I like the upper assembly of the older models better than the new ones. If you look to buy an older model, as with any used telescope, check it out--optics, upper and lower assemblies, focuser, check to see it can be collimated, and take it for a spin under the stars. Check out the sphere for dings and nicks since it must rotate throughout the sphere's surfaces. My 12.5 inch Portaball is about 18 years old. It is a great telescope. I store it on my side of the closet inside my house, avoiding a host of problems.

#4 GeneT

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Posted 10 July 2013 - 03:53 PM

I forgot--the older models have an upper assembly that will nestle inside the sphere. This allows the whole telescope to take up only the space of the sphere.

#5 peleuba

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Posted 11 July 2013 - 02:31 PM

I forgot--the older models have an upper assembly that will nestle inside the sphere. This allows the whole telescope to take up only the space of the sphere.


Yes, that is a big benefit of the older non-CNC upper cages - being able to nest it inside the sphere. This is currently being looked at now and while I don't think nesting will be an option there are a number of ways to attach it to the aluminum bezel on top of the sphere and have asked Dave to explore that avenue.

#6 mkothe

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Posted 14 July 2013 - 09:26 PM

Thanks for the comments, Paul and Gene. The nesting upper assembly is an important point for compact transport. I have done some more reading, and it seems the sequence of improvements is something like this, correct?

- Original version with aluminum ball and non-Zambuto mirror
- Zambuto mirror
- Fiberglass ball
- Focuser upgrades
- Vent holes in the ball, curved spider (or was this later?)
- New owner Dave Jukem 2008
- Strut upgrades, new upper cage (still nesting), new electrical, new stand
- CNC machined upper ring (non- nesting) and mirror cell

Does anyone know how frequent the electrical issues with the old design are, and how much it would cost to have Dave upgrade the wiring? Seems like many of the ads I've seen were non-committal on the state of the electrical system, so that's making me nervous.

Thanks again,
Michael

#7 Jarad

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Posted 15 July 2013 - 09:00 AM

I know Dave offers wiring upgrades. The main issue with the wiring is that there is a tendency to short out at the spot where it connects to the mirror cell. The original wiring sent the power to the cell, then to the switch for the fan, then back to the cell. So even when the mirror fan was off, the current has to go through the cell. I modified it by removing the wire from the batteries to the cell completely, and used a stereo wire to run from the batteries to the charging post on the sphere. So now current only flows to the cell when the fan switch is in the "On" position. I also added some electrical tape arount the contacts on the cell to prevent what I suspect was the partial short circuit (the cell itself was the ground terminal, now it is not).

It's not that hard to do if you want to do it yourself. I wouldn't let it stop me from getting a scope if you find one you want. You can also contact Dave Jukem to find out how much he charges for the wiring.

Jarad

#8 stevenwav

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Posted 15 July 2013 - 10:29 AM

Hey Mike - I live close to you and own a newer 12.5" Portaball. I am not trying to sell it but if you want to take a look at one in person, perhaps we can arrange it - just PM me. I had some self inflicted electric issues which have been resolved. It is a tremendous scope.

#9 Diana N

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Posted 15 July 2013 - 01:47 PM

I have done some more reading, and it seems the sequence of improvements is something like this, correct?

- Vent holes in the ball, curved spider (or was this later?)


Several years ago I bought a used 10" PortaBall which has the vent holes in the sphere but a standard 4-vane spider. So the curved spider must have come after the improved venting of the sphere.

Does anyone know how frequent the electrical issues with the old design are, and how much it would cost to have Dave upgrade the wiring? Seems like many of the ads I've seen were non-committal on the state of the electrical system, so that's making me nervous.


One thing to remember is that the wiring system isn't running anything absolutely essential to the function of the scope (especially if you can store the PortaBall someplace where it will be close to the ambient temperature outdoors). The scope is still perfectly usable if the electrical components die; you just need to swap out the special wired-for-dew-prevention Quikfinder for a regular Quikfinder. So the scope isn't a complete dud if you can't fix the electrical issue yourself and don't want to send it back to Dave Jukem for rewiring.

#10 Rinaldo

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Posted 19 July 2013 - 06:35 PM

My scope was from 2007, one of the last from Smitka. According to Dave, his new curved spider vanes are much thinner than what was on the composite UTA. I hope to see just how much thinner by some time next week, as mine is in his shop getting the upgrades done as I write this!

Ron

Thanks for the comments, Paul and Gene. The nesting upper assembly is an important point for compact transport. I have done some more reading, and it seems the sequence of improvements is something like this, correct?

- Original version with aluminum ball and non-Zambuto mirror
- Zambuto mirror
- Fiberglass ball
- Focuser upgrades
- Vent holes in the ball, curved spider (or was this later?)
- New owner Dave Jukem 2008
- Strut upgrades, new upper cage (still nesting), new electrical, new stand
- CNC machined upper ring (non- nesting) and mirror cell

Does anyone know how frequent the electrical issues with the old design are, and how much it would cost to have Dave upgrade the wiring? Seems like many of the ads I've seen were non-committal on the state of the electrical system, so that's making me nervous.

Thanks again,
Michael



#11 Joad

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Posted 19 July 2013 - 07:49 PM

My experience is quite consistent with what has been said here. I am the third owner of an older generation 12.5" Portaball. Having just cleaned the mirror yesterday I verified that my Zambuto mirror was made in 1998 and was number 008 of a series.

I have indeed had some trouble with the wiring (the dew heater on the secondary suddenly quit without warning a while back), and I've experienced (without changing anything) the sort of weirdness with the fan wiring that Jarad describes. I've replaced the battery when it would no longer take a charge, which wasn't a problem, but when the original Mag 1 charger quit (and no electrician would attempt to repair it) I could not find an equivalent replacement (even when I contacted Dave Jukem directly by phone about it). I now use a cheap (and not very reliable) charger that charges the battery through direct connection to the terminals. At least the fan still works.

The good part is that the wiring isn't really all that important. The basic design is so simple, so oriented towards completely manual operation, that I'm not overly concerned about a fan failure. I can see from the comments here that that can be addressed if it comes to pass.

Thus, there is one advantage to getting an older Portaball if it is in good shape: it will be a lot less expensive than a new one. I am NOT (I repeat, NOT) criticizing Dave Jukem at all, but the Portaball is a pretty pricey item. Used Portaballs generally go for about half of the new ones. It is a significant difference.

#12 mkothe

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Posted 16 September 2013 - 10:50 PM

Hi again,

While this thread was slipping down in the forum, I was able to find a nice 12.5" Portaball with curved spider, vent holes (and functioning electrical system!) plus a tracking platform and other accessories, so I'm a happy camper! After selling most of the "extra" items, the scope with platform will be around the price or maybe less than one of the Synscan goto dobs I was considering, but much more portable. Unfortunately I have been very busy lately and have not had much time with the scope, but what a nice fit and finish! It's actually fun to put together, and collimating is so easy. As an added bonus, we will be moving to a significantly darker and less obstructed house in the suburbs, so my observing experience should get much better all around!

Thanks again to all for your input,
Michael

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#13 GeneT

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Posted 17 September 2013 - 08:01 PM

The good part is that the wiring isn't really all that important. The basic design is so simple, so oriented towards completely manual operation, that I'm not overly concerned about a fan failure. I can see from the comments here that that can be addressed if it comes to pass.


All my electrical stuff died. I chose not to rewire the telescope. My only concern was the fan not working. I leave it outside at least an hour before set up and I have had no problems with the mirror reaching and holding ambient temperature. It probably helps that I live in south Texas.

#14 davidpitre

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Posted 17 September 2013 - 09:09 PM

One thing I've always wondered about the Portaball is how a mirror at the bottom of a sphere can cool well.

#15 GeneT

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Posted 19 September 2013 - 03:22 PM

One thing I've always wondered about the Portaball is how a mirror at the bottom of a sphere can cool well.


That's a good question. However, I own a first generation Portaball and the sphere is made of aluminum. I have never had ambient temperature issues.

#16 Jarad

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Posted 21 September 2013 - 06:20 AM

The newer ones come with both vent holes in the sphere and a fan on the mirror. Combine that with a nice thin mirror and no problems.

Jarad

#17 bartine

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Posted 21 September 2013 - 10:05 PM

I had one of the older models with a JC Wilkenson primary. It was a fantastic scope - did have to do some minor re-wiring.

My mirror cell mounts came loose from the sphere, but contacted Dave at Mag 1 and he set me up with new mounting blocks for the mirror cell - fantastic customer service. Got aperture fever and sold it - but it was a fantastic scope. It was optically spectacular and so smooth...

#18 Peter Natscher

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Posted 21 September 2013 - 10:42 PM

What about the issue of how large an eyepiece a Portaball can handle? Can it handle a 2" wide-field eyepiece? What's the longest fl eyepiece/widest fov that can be used on a 12.5" Portaball before balance becomes an issue?

Hi,

I am still searching for my next telescope to upgrade from my 8" dob and have now arrived at considering a 12.5" Portaball. I have always been fascinated by what I read about these (and the Teleports) in terms of ease of use and mechanical and optical quality, and I think I could afford one at the lower end of the spectrum of what I have seen advertised. My question is what kind of compromises/issues would I have to contend with if I get a lower priced (and therefore possibly older) Portaball? I think I have read that older models had less reliable electronics or wiring. What other improvements have been made over the years, and when? How can I tell how old a given Portaball is from the description?

Thanks,
Michael



#19 mkothe

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Posted 21 September 2013 - 10:58 PM

I think that depends on how smooth the sphere is. If it's waxed too well you might run into problems, but mine came with a 35 Pan that is no problem. I even had an 8x50 RACI finder on there as well. But I have not used it extensively, so maybe that's too much in some circumstances. I have heard people use them with binoviewers, too.

#20 soupaman

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Posted 21 September 2013 - 11:18 PM

Here's my 8" with a 21 Ethos. It won't hold below 45 degrees. However, placing a towel or some type of micro fibre material under the sphere allows it to hold at a lower altitude. I would imagine the larger Portaballs would have less of an issue with heavy ep's. Dave at Mag 1 will add weight to the sphere if that's what is required by an owner.

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#21 Peter Natscher

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Posted 21 September 2013 - 11:22 PM

I have looked at the Mag1 website and found no price page. Does it take a phone call or email to get a Portaball price?

Hi,

I am still searching for my next telescope to upgrade from my 8" dob and have now arrived at considering a 12.5" Portaball. I have always been fascinated by what I read about these (and the Teleports) in terms of ease of use and mechanical and optical quality, and I think I could afford one at the lower end of the spectrum of what I have seen advertised. My question is what kind of compromises/issues would I have to contend with if I get a lower priced (and therefore possibly older) Portaball? I think I have read that older models had less reliable electronics or wiring. What other improvements have been made over the years, and when? How can I tell how old a given Portaball is from the description?

Thanks,
Michael



#22 Jarad

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Posted 22 September 2013 - 07:44 PM

What about the issue of how large an eyepiece a Portaball can handle? Can it handle a 2" wide-field eyepiece? What's the longest fl eyepiece/widest fov that can be used on a 12.5" Portaball before balance becomes an issue?


The issue isn't how heavy an eyepiece it can handle, it's how wide a range of eyepieces it can handle. You can adjust the amount of weight in the bottom of the sphere to handle whatever you want, but if you set it up to handle a really heavy eyepiece, then it may tend to lift up if you use a really light one.

I have mine set up to handle a 35mm Panoptic with a paracorr. I keep the paracorr in all the time, my lightest eyepiece is probably my 7mm Nagler T6. I have to be carefull with the 35 Pan below 30 degrees or so.

Jarad

#23 Rinaldo

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Posted 22 September 2013 - 09:11 PM

It would be easier to order it balanced for a heavy eyepiece, since you can always hook a removable weight up front for the lighter lenses.

#24 Rinaldo

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Posted 22 September 2013 - 09:15 PM

Pretty much. Dave keeps the Portaball updated with improvements, but he doesn't keep his site up to date! The latest version of the scope looks different in the UTA compared to what's pictured. He does pick up the phone though.

I have looked at the Mag1 website and found no price page. Does it take a phone call or email to get a Portaball price?

Hi,

I am still searching for my next telescope to upgrade from my 8" dob and have now arrived at considering a 12.5" Portaball. I have always been fascinated by what I read about these (and the Teleports) in terms of ease of use and mechanical and optical quality, and I think I could afford one at the lower end of the spectrum of what I have seen advertised. My question is what kind of compromises/issues would I have to contend with if I get a lower priced (and therefore possibly older) Portaball? I think I have read that older models had less reliable electronics or wiring. What other improvements have been made over the years, and when? How can I tell how old a given Portaball is from the description?

Thanks,
Michael




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