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by Allister St. Claire 04/17/03 | Email Author

Pete Smitka fixing the battery on my 12.5" mirror

A little background

" Pete, I snapped the electrical connector to my battery in my PortaBall, can you fix it?"

"Sure!" said Pete. "Why not come up to Mag 1 Instruments and I'll show you how the PortaBall's are made while I fix the wiring?"

As I write this I've been a 12.5" PortaBall owner for a little over 16 months. During that time Pete and I have spoken on the phone countless times as he patiently answered my endless stream of questions about the PortaBall. I must confess that I was tardy in reading the owners' manual that came with the PortaBall and found it easier to simply call Pete and pepper him with questions. Questions moved from the basics onto more advanced design discussions eventually culminating into the invitation above.

I was lucky to find a PortaBall on the used market as owners almost never sell these instruments. In my case, the person never took delivery and I was able to buy it from the dealer when I heard it was for sale. After owning it for 16 months I understand fully why these so infrequently appear on the used market. I'll talk about this later on in the article, but wanted the readers to understand my context (or biases) early on.

Mag 1 Instruments - a brief history

Pete Smitka is the owner and craftsman of the PortaBall line of telescopes. Pete's been around Astronomy for 40+ years. An active amateur astronomer and club president of his local astronomy club for a number of years, Pete fell head over heels in love with an unusually designed telescope that he saw at AstroFest in 1985 which was later shown in the Winter 1986/1987 issue of Telescope Making magazine. That design used an aluminum sphere to house the primary mirror and a clever counterweight system to keep it all balanced. Conceived and designed by a smart engineer named Thomas O'Brien, this scope made quite an impression at the star parties he brought it to, but it was rarely copied as it is difficult to execute. Another version of a sphere mount design was also seen in the late sixties. That scope, looking much like a giant AstroScan, was executed in fiberglass by Norman James, and appears in Textereau's book. So the concept is not new, but the commercial execution of a large, sphere mounted scope has been all Mag 1.

In 1990 Pete tried his hand at creating such scope himself and was surprised by not only winning an Award at Astrofest that year, but also by the amount of interest his creation attracted. Agreeing to custom make one for a local club member, Wanda Berner became Pete's first customer (she still owns hers today). From that point on Pete starting receiving increasing number of requests to custom make additional "ball scopes". In 1991 Mag 1 Instruments was offically started and the rest is history.

The PortaBall telescope - a quick look

The PortaBall is a premium, hand crafted alt-azimuth telescope based upon an ingeniously balanced spherical body. There are other premium telescope manufacturers out there but no one else makes one based upon the ball design. It is a unique product in which almost every piece of it is custom made. There are only a handful of off the shelf parts in a PortaBall and as you will see later on, there is good reason for this. As a side note, in the entire time I've known Pete he's only spoken respectfully of the other premium scope manufacturers. Never once did he say a disparaging word, or in any way push his PortaBall by pointing out the faults of the other designs. This at first surprised me but as time went on I learned two things:

  1. Custom craftsman respect each other for the simple fact that they are craftsman sharing the common values of only selling high quality products that meet their sense of perfection. Mass produced telescopes with wide variations in quality are the competition, not each others products;
  2. Each of these companies is backlogged months with orders... and probably always will be.

Consequently, these folks don't view themselves as competitors, but rather like kindred spirits who genuinely want to see high quality instruments in the hands of amateurs. In a country that has become culturally obsessed with quarterly profits and marketing, such a philosophy is refreshing.

PortaBall telescopes come in four aperture sizes; 8", 10", 12.5" and 14.5". Pete's designed the PortaBall line such that the 8" and 10" use the same size sphere, as does the 12.5" and 14.5". Differences exist in the size of the upper tube assembly and the weight of the sphere.

Mag 1 exclusively uses Zambuto mirrors in their PortaBalls . The Zambuto Optical Company has gained the enviable reputation of consistently producing the highest quality mirrors in the world. In fact, I have never met an unhappy Zambuto mirror owner. Amateurs rave to each other about the images they are getting from these mirrors, whether they are in a PortaBall or one of the competitors dobs.

When you order a PortaBall you have a menu of options to customize the scope to your needs--an electrical package for cooling the mirror, anti-dewing system for the secondary and finder, different types of finders, a choice of focusers, carriers, covers, and the list goes on. Additionally, the scope is not only custom balanced for your eyepiece selection (you'll be asked at time of order) but in the case of the 12 and 14" models custom built for your eye height as well, meaning its made so that the eyepiece is exactly at your eye level when the scope is pointed at zenith. This coupled with the full rotational capabilities of the scope, has the net effect of making zenithal viewing (the bane of most other telescopes) a most comfortable viewing position with a PortaBall, and also gives it the additional ergonomic quality of instinctive optimal eyepiece positioning, and fluidity of motion everywhere it is pointed .

I mention all this customization to give the rest of this article some context. As will quickly become apparent, craftsmanship and labor is what the PortaBall is all about.

Arrival at Mag 1 Instruments

Mag 1 Instruments is only 2 hours from where I live. Leaving early one Sunday morning I arrived at Pete's shop promptly at 9:00 AM , where both myself and PortaBall were quickly ushered in. While Pete began work on my electrical problem, I surveyed his shop.

As would be expected, there were parts of various size PortaBalls everywhere. Carefully poking around and tossing questions over my shoulder, I happily examined PortaBalls in different stages of completion. My questions became increasingly focused on how a PortaBall is made and Pete good-naturedly stopped working on my ball and spent the next two hours walking me through the rough steps of how a PortaBall is constructed.

Rough steps to make a Portaball

1. Fiberglass sphere

The birth of a PortaBall begins with the arrival of an empty fiberglass sphere. These are made specifically for Mag 1 in propriety molds by another Wisconsin amateur astronomers business. At one time the PortaBall line was created using spun aluminum spheres. Today, all Portaballs are made using these fiberglass spheres as they offer the distinct advantage of being far tougher then aluminum. Pete demonstrated this by pounding a ball with the side of his fist as hard as he could for several seconds. Other then leaving a welt on his hand, the sphere didn't have a mark. Pete reports it would take a dramatic accident to break or damage a fiberglass sphere. Pete uses the example of a boat which is also made out of fiberglass - how tough is a hull?

A recent modification has been made to speed cooling, Pete drills 9 7/8" holes around the bottom circle of the sphere. These holes allow the fan to draw air from outside of the sphere and blow it onto the bottom of the mirror. This innovation, along with the new mirror cell (discussed in step #4) decreases cool down a whooping 50%.

2. Upper ring assembly is hand drilled and installed

Next the upper black ring assembly is custom drilled, the parts and wiring is installed, before mating it to the lip of the sphere. The ring itself comes as a featureless black (anodized) ring, and spun from aluminum specifically for Mag 1. The vent holes noted above are then located and drilled.

3. Mirror cell supports, counter weights and insulation are installed

Next the mirror cell supports (3 black arms ~2/3 of the way down the sphere) are installed along with the counterweight and insulation. The insulation protects the mirror from the heat that would bleed off from the counterweights if the insulation wasn't there, and which then primarily radiates from the sphere shell.

4. Install the mirror cell and sphere electrical package

Next comes the mirror cell and the wiring of the sphere electrical package (if that option is ordered). Pete has recently redesigned the mirror cell, using Finite Element Analysis to control flexure loads. Improvements include a 6 point mirror support (the old one was 9-point) and larger clearances to increases the airflow under the mirror. A new larger (92mm), higher volume (55 cf/m) fan is included to speed cool down if you buy the sphere electrical package. The gel cell battery is installed as part of the mirror cell, and serves as a counterweight to the focuser/eyepiece on the top part of the telescope. It is designed to be left plugged into a charger when the scope is not being used, and has the bonus of a sensor circuit so you can't over charge the battery.

6. Mirror is installed

Carefully, the primary mirror is installed into the mirror cell. After mechanical centering , installation involves using a flexible silicone adhesive to attach it to the six support point, and is also injected through the six side supports, following a process suggested by Richard Berry. The picture above shows the mirror cell (right) and the primary mirror installed into the mirror cell (left)

7. Make the truss poles

Pete fabricates the truss poles himself from raw aluminum tube. After cutting to a standard length, they must be annealed cushed at one end, then drilled and sent to be anodized. After that they are made to correct length for a given telescope/eyepiece combination after determining the focal point of that scope. Pete also adds vibration dampening materials inside them at the time the lower attachment parts are installed. Without this material, the truss poles would transmit the vibrations (minutely) and disturb the image at the eyepiece.

8. Upper Tube Assembly

The upper tube assembly arrives to Pete as a cylinder, and is constructed as a fiberglass composite. The outer layer is a high pressure laminate, the 3/16"core foam, and the inner layer a fiberglass cloth. The end rings are then bonded to the cylinder and the various mounting holes must be drilled.

9. Secondary spider and optional electrical anti-dewing elements

Once the fiberglass upper tube assembly is ready, Pete then installs electrical items and hand wires them to a conductive tape laid on its inner surface. The spider and secondary mirror assemblage are similarly installed and wired. By using low profile focusers, the secondary mirror on each PortaBall can be minimized. The resultant 18% obstruction gives the owner maximum contrast for demanding planetary viewing and nice tight stellar views. The secondary is then wired with an automatic dew heater, while the finder is fitted with a fixed level type. This neat device from AstroSystems automatically senses the difference in temperature between the outside air and the mirror surface. At a threshold differential of 2 degrees it automatically turns itself on so you never have to worry about your secondary dewing over.

10. Epoxy over all the wiring

All the wiring in the scope is covered with a thin layer of epoxy to protect it from the elements and abrasion from storing your gear inside when the scope is disassembled, before being painted flat black. The glass cloth layer on the inside of the upper tube has thousands of "pockets" which give it a low reflectance due to their light trapping effect.

11. Initial star test to determine the length for the truss poles

Because there are minor differences in focal length in the mirrors and some variations in every telescopes mechanical set-up, Pete must now determine the exact length of the poles using a star image so that a telescope achieves critical focus for your eyepieces. This involves setting up the scope with a standard set of trusses to determine the exact location of the focal plane before making them to the identical lengths (.001) needed to make them interchangeable on the scope. Once completed, the PortaBall is then balanced to accommodate the customers average eyepiece weight by adjusting the counterweight's mass.

12. Star test at night

No PortaBall is shipped until Pete has spent an evening under the stars with it. All points of the ball must meet his rigid standards and there is no better way to determine this then through an observation run. Each mirror is star tested and any problems found during this session means it goes back to the shop for a rework. Nothing leaves Mag 1 until perfection is attained. This step is one of the things never done by the mass merchandisers, and we saw in Hubble's blurry vision what happens if you don't test things together.

13. Make the stand to customer specs

Each PortaBall stand is custom made to the customers height. By changing the length of legs, Pete manipulates the height of the eyepiece at zenith. For those who are growing or shrinking in size, never fear, the legs can be reworked to accomodate your new height. Only after the scope is finished can the legs length be determined.

Time and commitment

The above 13 steps represent only the largest steps of the process. There are dozens of other smaller steps have not been documented but are no less labor intensive -like fabricating the mirror cells and many small parts, plus the many accessory items. As I stated earlier, there are only a hand full use "as is"of off-the-shelf parts in a PortaBall. Most parts must be custom fabricated for, or by Mag 1. That means, like a Mercedes, or any other fine object, it is very much hand crafted.

At this point you might be wondering how many man hours Pete puts into each ball? Hold on to your hats as the number is 50-60 hours. That's right, a complete weeks full of work with overtime included. My questions about speeding up the process with some semi-assembly line work or sub-contracting was met with the same enthusiasm craftsman from other fields have demonstrated (furniture and musical instruments in my case) - a glassy eye stare and expressions of incredulity. It's not that folks like Pete don't understand these business concepts. It's that they are craftsman, willing to turn out a relatively small number of instruments that meet their exacting standards.

Some questions for Pete

1. What do you think of the instruments being produced today for amateur astronomers?

I think amateurs today have the largest selection of instruments available to them then ever before in the history of this hobby. Back when I started in amateur astronomy, the only way you owned an instrument was when you made it yourself. This deterred a great number of people from joining the hobby. I would guess there are record number of people participating in amateur astronomy and part of this is due to the relative ease in which a beginner can get a hold of a quality instrument.

2. What do you think of GOTO telescopes?

Many amateur astronomers tell me that part of the enjoyment they receive from this hobby is in finding objects. Learning how to properly read star maps, honing their detection and star hopping skills and the thrill they receive when they find that elusive target. GOTO telescopes bypass this entire entire section of the hobby and for some people, this will be a real loss. It's sort of like saying you went fishing when you bought your fish at the market. Like fishing, it's the process of fishing, and not just catching a fish that leads to the satisfaction.

3. What advice do you give on eyepiece selection?

I think eyepieces are the most subjective and personal part of this hobby. An eyepiece that one amateur loves, another amateur will hate even in the same instrument. Given reasonable optical quality, amatuers should feel unfettered to discover and use the eyepieces that THEY enjoy. While I have some eyepieces listed on the Mag1 Instrument web site, I'm always upfront in explaining to people that they are eyepieces I like. What they will like may be totally different.

4. Has the PortaBall design been improved over the years?

Each PortaBall that ships is slightly better then the last one. This not only reflects the perodic improvements that are made to the design, but also our finding better ways and materials with which to produce them. We never stop thinking of ways to make the PortaBall a better instrument for amateurs. Take a look at our web page and read about all the improvements and refinements that we've made over the years.

5. Can you give us a hint of things to come from Mag 1 Instrument?

Next year we will be introducing the biggest Portaball yet and the last of the Portaball family - an 18" light weight, sphere-based design. I will be releasing details later this year and hope to begin production 2nd quarter of 2002.

6. What things would to encourage amateurs to do.

To have fun! Amateur astronomy is a hobby whose aim is to provide relaxing, but intellectually stimulating diversion. If you go to a star party and it rains, break out the cards or go on a group trip. If it clouds over, huddle up in a building or tent and figure out a way to have some fun. Amateur astronomy is a journey, take the time to enjoy both the trip and your fellow passengers.

Secondly, make trips to dark sky sites. It's odd that in other hobbys (scuba diving, car racing, skiing, etc) people think nothing ot taking trips to engage in their hobby. Yet, many amateurs don't plan trips to visit dark sky sites to engage in amateur astronomy. The visual boost you receive from a dark sky site is tremendous and must be experienced to be believed.

Finally, don't be afraid to spend some money on your hobby, since unlike most other kinds of hobbies our equipment doesn't wear out, so it also doesn't depreciate. Most people spent many $1,000s on their hobby each year. plus yours has no operating costs. Compare that to boating, flying, skiing, snowmobiles, scuba diving, or any other hobby using equipment and you'll see what a bargain the hobby is even if you spent a fair amount on your equipment. Your stuff will never wear out, plus it has no operating costs, licenses fees, and virtually no maintenance. From the standpoint of a manufacturer you should also know this, the products you buy are usually sold at mass market prices, even though they are custom made. Margins are thin for everyone in this tiny hobby, which is why there are no chain telescope stores, and very few telescope stores anywhere. If you have a local store, support them, or they won't be there when you need help.

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