Here are the places that supplied the parts I bought for the scope. Where possible, I have included links to their web pages. This isn't a comprehensive parts list. In particular I have omitted the nuts, bolts and other bits and pieces I picked up in over two dozen trips to the hardware store.
Steve Swazy did the mirror. A couple friends in the NSA recommended his work. He was my first choice so the fact that he could make the mirror to the diameter and f-ratio I wanted were a great relief.
I ordered the mirror around March 15. By the end of June, Steve was done grinding the mirror and had sent the mirror to the coaters. It arrived in my hands on August 7, 2002. Subsequent use and star tests have revealed the mirror to be superb. It has performed wonderfully and received numerous complements. I wouldn't hesitate to order another mirror from him in the future if I ever build another scope.
ProtoStar provided the secondary mirror. My friend Mike got one of their quartz secondaries and absolutely raved about it. Unfortunately, they don't make them in quartz for the 2.6" size, so I had to go with standard Pyrex instead.
I also liked their secondary holder/spider system. It looks like it would be easy to use. More importantly, it is short enough that I could build a secondary cage around it that would fit in the trunk. So I was crushed when I found out that the lead-time would be 20 weeks to get one. Balance is determined mostly by the weight and height of the secondary cage. And much of the size of the secondary cage is determined by the height of the secondary holder. So 20 weeks was just too long to wait for one of the most critical components to the overall design of the scope. I knew I would have to get these components elsewhere.
I also bought some "flocked paper" from them. It has a texture that is best described as 'peach fuzz'. The fibers aren't supposed to shed like some velvets and felts do. I intended to use it on my light baffles. Unfortunately it pealed off when water in the air hit it. They suggest using a special type of adhesive to stop this from happening. In an act of frustration though, I ended up removing it and replacing it with sawdust sprinkled onto black paint and covered again with black paint.
AstroSystems supplied the secondary mirror holder and spider. When I was doing my original shopping for these components, my chief problem with their solution was that it was too tall. The standard setup for them with my secondary mirror size is 7.3" from the center of the mirror to the end of the nut. This was a problem since I wanted the total height of the whole secondary cage to be less than 7.75". I talked to them on the phone though and said that they were able to make a custom spider for me that is shorter than what they normally produce, knocking a couple inches off the height. They warned me that vibration might be a problem, but I decided to give it a try anyway. If vibration in the spider is a problem, I haven't noticed it yet.
I also picked up a secondary mirror warmer from them since I expected that the open truss design would have issues with dew. So far, dew on the secondary hasn't been an issue. I can't say if this is because I typically use the mirror warmer and it is working or if I just don't need it.
They also recommended using some Formica they sell for a light baffle instead of Kydex. It has worked just fine and I even ordered more of it later in the construction. I hear that they have since run out though. The double-sided tape they sell to attach the Formica with worked really well. I was worried it wouldn't stick very well, but as it turns out the Formica will start to break before the tape will let go.
Ever since I first laid eyes on the Starlight Instruments focuser, I wanted one. It was the first thing I bought for the scope, as it was the only thing I always was sure would be part of the final design. ABSOLUTELY everyone who's touched the scope has commented on how much they like the focuser.
One good thing about buying the focuser first is that when it arrived, I realized that I hadn't really been working as hard on the design as I should have been. Getting the focuser actually motivated me to finish the design and start construction. I loved it so much I feared I would feel sick if it never made it into a finished scope.
I found out that Owl Hardwoods in Des Plaines, IL has Baltic Birch plywood. They are located at 926 S. Graceland (Rte. 45), IL, one block south of Thacher/Dempster. Their phone number is (847) 824-5025. Owl is a dangerous sort of place if you love fine woods. They were also very helpful. I purchased from them a half sheet each of 1/4", 1/2" and 3/4" Baltic Birch. I also got some birch edge banding (veneer) to cover over the edges of the plywood.
My big mistake when shopping here is that I didn't really prepare and know exactly how much wood (and edge banding) I was going to need. I am used to thinking of plywood as being cheap, junk wood. So I went in thinking that if I bought too much I'd be out a few bucks, but it would be no big deal. After all, plywood can always be used later for another project. I should have better heeded Kriege and Berry's warning about how heart breaking it is to see all the wood that is wasted when building a scope. Baltic Birch is far too beautiful to use carelessly. I was glad Owl let me buy half sheets so I wouldn't have so much left over. Given how pricey Baltic Birch is, saving a few bucks didn't hurt either.
In one of his most inspired moves, Del motivated me to try out carbon fiber tubes for the trusses. He found Avia Sport Composites, which is mostly in business to service kite builders. I had to hold in my hands a sample that Del bought before I could appreciate how stiff and light they are. It's amazing.
I purchased some of their pultruded carbon tubes. The largest diameter tube they sell is 5/8". I was able to get them to make up some 60" long instead of their standard 48" length for about $13 each. Good thing I had to shave a couple inches off because they just barely fit in the car with the top down.
The small diameter is the key to the usefulness of these tubes. Getting 1" diameter aluminum tubes to connect to a 1" wide secondary cage ring would be a lot harder than using 5/8" diameter tubes. Worth every penny.
The actual secondary cage was built according to the design suggested by Kriege and Berry. There was an aborted secondary cage built out of foam though. For it, Owl provided the birch wood veneer. The foam came from a 4' x 8' sheet of 1.5" thick standard pink foam insulation that Del got from a local hardware store. The giant sheet was almost completely consumed in the process.
I love my old Telrad, but the Rigel finder is easier to use and more important lighter, so I grabbed one of those. While some people don't like it, I find the "blink" feature to be a huge help. There have been many times when I lost dim objects in the Telrad because it's light overpowered what I was trying to spot on. Plus I like how they include two base pads so I can use the same Rigel finder on both the Miatascope and my 6".
I purchased Sky Commander's digital setting circles (DSCs). One thing I liked about their unit was that I wouldn't have to be paranoid about how fast I was slewing the scope before the encoders got all confused. Checking with AstroSystems, I found that the encoders sold with their Sky Commander units were going to have a low enough profile to work with my design.
With everything else I was buying from AstroSystems, I went ahead and got their pivot bolt kit and their Teflon bearing pad kits. One thing that was very helpful to know was that the height of the Az. encoder when it is attached to the pivot bolt is 1.1". This made clearance calculations possible. Last thing I wanted was to spend roughly $500 on digital setting circles only to find that I didn't have the clearance to make them work. Knowing that the hole in the pivot bolt for the DSCs was perfectly square as also a comfort.
On page 122 of the October 2003 issue of Sky and Telescope magazine there is an article titled "Better Dobsonian Bearings" by Martin Lewis. Lewis suggests replacing the Teflon in the Dobsonian bearings with perfluoroalkoxy fluorocarbon or "PFA". So I bought a 1/4" thick chunk of grade 350 material.
The supplier mentioned in the article is Boedeker Plastics (800-444-3485) so I used them. They ended up charging a lot more than the amount mentioned in the article. This was due to an error on the part of the person who took my order. Instead of giving me the 6 square inches I asked for, he sent a 6" x 6" piece. With six times as much material as I intended to order it is not too surprising it cost $51.00 which is a bit over the $15.00 price mentioned in the article. I would have sent the extra back, but I figured that perhaps having some spare material would be a good thing.
I knew when I built the scope that frequent collimation would be required. I didn't truly see the light, so to speak, though until one of my fellow members of the NSA (Darren) stopped by with an EZCollimator available from AstroSystems. I've never seen such sharp images from any scope I have ever owned. It was like all of a sudden I could really focus an image rather than just find the least annoying blur.
As much as I loved my EZCollimator, it had one design flaw that in the end was absolutely fatal. When the batteries died, replacing them was a nightmare. The replacement required that I remove the laser pointer from inside the unit. After that recollimating the collimator while keeping the laser beam centered on the hole it shines through took forever. I never was able to figure out for sure what batteries it used. The batteries I tried only seemed to last an hour or so before the beam went dim. Since it takes about 5-10 min. to collimate the scope, this meant that there weren't many setups between replacements. In an effort to reduce the time between battery replacements, I put an extra battery in which I think eventually fried the laser over time.
So I switched to the Kendrick collimator with I also purchased from AstroSystems. It uses a battery pack that is not inside the laser itself. So changing batteries does not affect its collimation. I doubt that I will ever need to collimate this collimator. In fact, Kendrick recommends sending the unit back to the manufacturer if its collimation ever goes off kilter.
The only problem with this unit is that the user really needs to be able to look up towards the focuser from the bottom of the telescope tube. This of course isn't a problem with the Miatascope and its open truss tube design. I also don't have a problem with my old 10", which has an open mirror cell to look through. My old 6" though has a cap over the bottom that prevents my using it with that scope. For now I will just use alternate methods to collimate it.
One of the things that drove me nuts about Kriege and Berry's book was that the lack of detail about the "threaded inserts" they suggest for the secondary cage. I couldn't find them anywhere except to buy them from Kriege through Obsession telescopes. Since he doesn't take credit cards, getting these fast is impossible and I needed a solution literally over night. In the end I stuffed a bit of dowel rod down the aluminum tube and used screws to hold the dowels in place so the final secondary cage would ready in time for it to be ready for the scope's debut at Astrofest 2002.
It was too late for me, but I can help you with this problem. Again it was Mitch, a fellow member of the NSA, who helped me. He told me that the threaded inserts are called "Star Fangled Nuts" and they are used in making bicycles. Even though I didn't need them any more, I went ahead and bought some anyway from WebCyclery.com. I think I paid about $3.00 each. If I decide to do another iteration of the secondary cage, I will use these instead of the dowel rods.
Since AstroSystems didn't have any more of the Formica I was using for shielding, I needed another source of plastic for my light secondary cage light shield. After wracking my brain for months, inspiration struck and I found the plastic at a store that makes small, custom signs. I picked "FastSigns" because I could walk there during my lunch hour. They are located at 213 E. Ohio St. in Chicago, IL 60611 and their phone number is (312) 464-1800. My salesperson, Marisa was able to remember some really tough, black polycarbonate plastic they had in back which turned out to be perfect for my needs. She claims that the material is UV resistant and is so tough it is used in bulletproofing. She was really helpful and great to work with. I bought two 20"x31" pieces for about $55.00.
All together I spent around $4,250 in the construction of the Miatascope by Astrofest 2002. This price is somewhat inflated by items that aren't actually part of the scope however. I spent around $750 for various tools I didn't have access to. There was also another $250 spent on a luggage bag for the Miata that I need to put the eyepiece cases and camp gear in when I have a passenger. Things like that along with all the bits and pieces I bought and ended up not actually using probably added about $1,000 to the final cost of the telescope. So I would estimate that a frugal builder who thought things out better than I and who doesn't need any tools, router bits, etc. could build the MiataScope for around $3,000 - $3,250.
Some would argue that there are cheaper 15" scopes out there. True enough, but they don't fit in a Miata.
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Last updated 1/12/06