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Post by Ron Walker on Aug 24, 2022 10:28:30 GMT -7
Posted by: Ron Walker Nov 6 2007, 01:29 PM The time has come to begin the tale of the reconstruction of my Spitz A3P. The plan is to get this 40 year old machine back up and running and in dependable condition. Also to add some personal refinements. First (as the size of virtually all planetarium projectors surprises me) I put all the sections together and took this picture with me to give the machine some perspective. The next time it will look like this will be when it is ready for operation once again.  In another thread I went over the star globe and the arc lamp as well as a conversion for use with a stinger lamp. Since that section of the projector has been covered I will now go on to the other and more complex sections of the machine. Wish me luck! Since I may run into problems or have to wait on parts, I may jump around a bit as I work on the unit. I will also try and give my reasoning for doing anything that I do. Perhaps I should start with my philosophy of reconstruction. First I am not a true purest. What that means is that I will rebuild this projector to be functional as I want it to be functional. I'll further clarify in saying that while I very much like the idea of keeping the unit very much like the original, what is most important to me is the operation of the planetarium, not necessarily the way it was originally constructed, but to operate the way I would like it to. In other words I might want it to run at different speeds then it was originally intended to do. With that said, please join me and this true odyssey into the strange world of the planetarium "nut". |
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Post by Ron Walker on Aug 24, 2022 10:29:33 GMT -7
Posted by: charles jones Nov 7 2007, 04:01 AM
good luck, Ron!!!
By the way, will you be using the slip rings you posted pictures of on this projector, or was that just for exiperiment?
Charles
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Post by Ron Walker on Aug 24, 2022 10:30:03 GMT -7
Posted by: mrgare5050 Nov 7 2007, 05:28 AM
how do you move that thing around? looks like the starball's hitting the ceiling
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Post by Ron Walker on Aug 24, 2022 10:30:30 GMT -7
Posted by: SteveDurham Nov 7 2007, 06:01 AM
That will be fun to play with, when Marge and I get around to taking the trip to visit the Great Southwest!!
I guess we can give you about 3 years.
Steve
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Post by Ron Walker on Aug 24, 2022 10:33:02 GMT -7
Historical note: Steve and Marge never came in 2010. Actually I'm still waiting. It was worth the wait (I think).
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Post by Ron Walker on Aug 24, 2022 10:34:57 GMT -7
Posted by: Ken Miller Nov 7 2007, 08:38 AM
QUOTE(mrgare5050 @ Nov 7 2007, 04:28 AM) *
how do you move that thing around? looks like the starball's hitting the ceiling!
It looks like the A3P and Ron are both scraping the ceiling. It must be the camera perspective, or the ceiling is particularly low, or Ron is really 8 ft tall!
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Post by Ron Walker on Aug 24, 2022 10:35:42 GMT -7
Posted by: Ron Walker Nov 7 2007, 01:16 PM
QUOTE(mrgare5050 @ Nov 7 2007, 05:28 AM) *
how do you move that thing around? looks like the starball's hitting the ceiling!
As Ken says, "Perspective, my dear boy, perspective."
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Post by Ron Walker on Aug 24, 2022 10:37:03 GMT -7
Posted by: Ron Walker Nov 7 2007, 01:21 PM
QUOTE(charles jones @ Nov 7 2007, 04:01 AM) *
good luck, Ron!!!
By the way, will you be using the slip rings you posted pictures of on this projector, or was that just for exiperiment?
Charles
Actually a little of both. One thing I want to add to the A3P are several constilation projectors that will operate independently of each other and yet are always aligned properly. I would also like to add some more deep sky objects to the system. I really think there should be something for the Orion nebula at least.
I will have the construction of the slip rings down to a "science" so if you need me to make you a few, just ask.
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Post by Ron Walker on Aug 24, 2022 10:38:02 GMT -7
Posted by: Ron Walker Nov 7 2007, 01:24 PM
QUOTE(SteveDurham @ Nov 7 2007, 06:01 AM) *
That will be fun to play with, when Marge and I get around to taking the trip to visit the Great Southwest!!
I guess we can give you about 3 years.
Steve
By that time I should hopefully have a permanent dome for both the scope and planetarium. Also an outpost at WRN. Look forward to meeting you both!
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Post by Ron Walker on Aug 24, 2022 10:40:43 GMT -7
Historical Note: Actually it took until 2014 or seven years for that to come to pass. But then, as many of you know, things expanded a bit.
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Post by Ron Walker on Aug 24, 2022 10:41:59 GMT -7
Posted by: charles jones Nov 7 2007, 08:12 PM
QUOTE(Ron Walker @ Nov 7 2007, 12:21 PM) *
Actually a little of both. One thing I want to add to the A3P are several constilation projectors that will operate independently of each other and yet are always aligned properly. I would also like to add some more deep sky objects to the system. I really think there should be something for the Orion nebula at least.
I will have the construction of the slip rings down to a "science" so if you need me to make you a few, just ask.
Ok, I may take you up on that after the first of the year. I've decided that one of the first things I need to make are the slip rings.
The thickness, including the brush assembly, will determine the position of the tilted (23.5 deg) plate on the north and south assemblies. I can't build anything beyond the central core until the slip rings are made.
Charles
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Post by Ron Walker on Aug 24, 2022 10:42:27 GMT -7
Posted by: charles jones Nov 7 2007, 10:32 PM
Ron, in a post way back when, you had thought that the daily motion motor and/or latitude motor was contained in the base.
Is that true? One motor, two?
Charles
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Post by Ron Walker on Aug 24, 2022 10:46:16 GMT -7
Posted by: Ron Walker Nov 8 2007, 09:59 AM QUOTE(charles jones @ Nov 7 2007, 10:32 PM) * Ron, in a post way back when, you had thought that the daily motion motor and/or latitude motor was contained in the base. Is that true? One motor, two? Charles As the re-build takes place all questions will be answered. But I can answer this one first. The bottom of the A3P mounting plate contains two DC motors. One for diurnal motion and one for latitude motion.  Looking directly up at the bottom of the main support plate we can see the two motors and the various terminal strips used to connect the various functions of the projector. Two of these strips send wires up the hollow support posts into the projector via slip rings. The other two supply power to the many auxiliary plugs that are built into the base. |
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Post by Ron Walker on Aug 24, 2022 10:48:55 GMT -7
Posted by: Ron Walker Nov 8 2007, 10:15 AM When I started my first real job back in the late 60's, I was a lab tech at the University of Chicago. One of my jobs was the design and building of prototype experimental equipment to do very specific jobs. Everything was made out of blocks of aluminum and brass and had a "box'ie" very special look. I was immediately reminded of that when I started the re-build of the A3P. Everything on this projector looks hand made from blocks of aluminum and brass. As I have had a chance to view an A4 up close, I found much more use of special castings rather then just machined blocks bolted together to make the A3P. This is perhaps why I have such a soft spot for the machine as it looks just like something that I would have built. It is also built and perhaps "overbuilt" of gears and parts that come directly from catalogs that any true "tinkerer" drools over. This is perhaps most evident in the central core.  The two drive motors for the daily and latitude motion are placed below the main bottom support plate which would normally be hidden in the wooden support base. All of the electrical connections for the projector reside in this space. The main reason for the wooden base to to support the projector and raise it to the level of the spring line. In actuality, the latitude axis is approximately three feet above the hexagonal base plate. There are two main tube supports from the base plate that hold each side of the central core. They are hollow and the various wires that carry power up into the projector are contained within. There are also two 1/4 inch rods (one on each side) that provide rotational power for the diurnal motion and the latitude motion. |
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Post by Ron Walker on Aug 24, 2022 10:54:45 GMT -7
Posted by: Ron Walker Nov 8 2007, 03:19 PM The east/west axis of the projector is supported in two large blocks of aluminum supported by two legs each. These are covered by a protective cover made out of thin brass sheeting. Removing these covers exposes the gearing for the diurnal and latitude motion. On the east side is the worm gear for the latitude drive.  The drive shaft connects through two universal joints to drive the worm which is connected to the latitude shaft. note the half ring on the outside of the worm gear that is used to engage a micro switch and thus change the north and south indicators when the north latitude goes through and to the other side of the zenith. Just inside the aluminum block and past the main bearing is a set of slip rings.  On the west side of the longitude axis is the drive for diurnal motion. Note that this is just a 90 degree gear as the motion must be transmitted to the central shaft.  This drive shaft is placed in bearings that are in the center of the longitude main shaft. The longitude shafts terminate in either side of the central core diurnal drive box. |
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