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Post by Ron Walker on Sept 7, 2022 11:12:31 GMT -7
Posted by: Ron Walker Jul 5 2008, 06:00 PM Then comes the apparent solar time
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Post by Ron Walker on Sept 7, 2022 11:13:00 GMT -7
Posted by: Ron Walker Jul 5 2008, 06:05 PM followed by sidereal time and finally a readout for the direction of the sunset and sunrise glow.
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Post by Ron Walker on Sept 7, 2022 11:17:52 GMT -7
Posted by: Ron Walker Jul 5 2008, 06:23 PM One of the things that I still cannot get over is how strong this projector is built. Here is a shot of some of the Moon gearing. All of the gears are about 1/4 of an inch thick. Even after 31 years of service there is virtually no wear. Also it is uncanny how closely this projector follows the Zeiss II (or actually III/IV) design. In this view of the Saturn projector you can easily see the orbital tilt and again the very heavy gearing. Every shaft is set in ball bearings. The Venus projector front view shows the two projector system for the planets. Also note the plate just above the Venus drive gear (on the bottom of this picture) which is held in place by three support rings (one visible directly in front of the disc). Most small projectors do not allow for the eccentricity of the planets orbit. The Zeiss does and so does this Minolta. The reason for the plate is to take the accuracy even further. Having the planet gear offset would allow for eccentricity but could not allow for the slight change in speed that a planet goes through because it is closer and further from the Sun as it orbits. This allows for that change. I find this an amazing attention to detail, one I thought only Zeiss corrected for.
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Post by Ron Walker on Sept 7, 2022 11:19:35 GMT -7
Posted by: Ron Walker Jul 5 2008, 06:30 PM Because of the much larger eccentricity of the planets Mars and Mercury, this mechanical arrangement has been expanded to a three link mechanism to maintain accurate placement. In this side view of Mars this linkage can be seen quite clearly. A back view of Mars reveals the slide rod that supports the double projector from the Mars orbit. The more I look at this machine, the more that I'm amazed by it. I will be posting some comparison shots of the Zeiss to show how well it was followed. I guess that when you lose a war, everything is up for grabs.
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Post by Ron Walker on Sept 7, 2022 11:20:01 GMT -7
Posted by: Owen Phairis Jul 5 2008, 08:11 PM Thanks Ron, I find this all very exciting and educational. I had hoped you would have ended up with more manuals. I feel a lot of projectors from that era had major upgrades to computer control over the years to their motions so they could be better tied into their planetarium shows. The software and interconnect often becomes a problem when you don't get the computer with the projector or the schematics. Better sometimes to start from scratch. Again congratulations, Owen Planetarium Projector Museum www.pictorialism.com
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Post by Ron Walker on Sept 7, 2022 11:21:11 GMT -7
Posted by: Ron Walker Jul 6 2008, 11:34 AM QUOTE(Owen Phairis @ Jul 5 2008, 08:11 PM) * Thanks Ron, I find this all very exciting and educational. I had hoped you would have ended up with more manuals. I feel a lot of projectors from that error had major upgrades to computer control over the years to their motions so they could be better tied into their planetarium shows. The software and interconnect often becomes a problem when you don't get the computer with the projector or the schematics. Better sometimes to start from scratch. Again congratulations, Owen Planetarium Projector Museum www.pictorialism.comYour quite right Owen. One thing that appears to be quite consistent about Viewlex of the period is that they added their own electronics for automation. My E-5 was a Viewlex hybrid and the Viewlex electronics was in a word "terrible". I tried rebuilding one section and even with new parts the dimming was terribly jerky. The projector itself is built like a tank as is the Minolta so it was easy to replace the questionable parts with a simple direct drive system. The Minolta is ten years newer then the E-5 and Viewlex had moved on from importing Goto to Minolta. Personally I think Goto just had such a bad experience with Viewlex and the bad added electronics that never seemed to work right, that they terminated the association. Viewlex went belly up sometime in the mid 70's so this is probably one of the last Minolta projectors incorporating Viewlex electronics. It was a totally solid state dimming system that could be controlled by a four track, 8 track type recorder. I did get a maintenance logbook with the projector which was very detailed for a period commencing with procurement in January of 1977 and ending in December of 1991. The electronics started causing problems in April of that year, and the tape system that ran the automation was a headache from May on. The only mention of the projector itself was simple cleaning of slip rings and the occasional bulb replacement. Things got so bad that in November of 1990 they replaced the entire Viewlex control and automation system with a Screenmaster system by Joe Hopkins Engineering. The job took 100 hours over a five day period. Projector maintenance was turned over to Minolta at this time and the log book ended. As I mentioned before, Joe never made any schematic drawing of his changes. Some of the Viewlex electronics was removed from the original Viewlex rack and incorporated into Joe's changes. The automation (Joe's system) was not part of the deal and was basically cut out of the system. Since it all ran on a IBM486 (the computer of the time) and they wanted to keep it for programing. I am assuming that the Minolta/Viewlex electronics are as bad as the Goto/Viewlex ones, so I will not even try to get them working again. Since my plan is to give live shows and not programs like "Larry, Cat in Space", it should be no problem to get the projector up and running very much like the E-5 and A3P before it. I will try and get the existing control electronics up and running as I would like to be able to use the controls on the classic control panel. However, I will not waste a lot of time on it. If problems occur, I will run the machine with a simple direct system and then perhaps play with the old circuits as time permits.
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Post by Ron Walker on Sept 7, 2022 11:21:46 GMT -7
Posted by: Owen Phairis Jul 6 2008, 01:16 PM QUOTE(Ron Walker @ Jul 6 2008, 11:34 AM) * Your quite right Owen. One thing that appears to be quite consistent about Viewlex of the period is that they added their own electronics for automation. My E-5 was a Viewlex hybrid and the Viewlex electronics was in a word "terrible". I tried rebuilding one section and even with new parts the dimming was terribly jerky. The projector itself is built like a tank as is the Minolta so it was easy to replace the questionable parts with a simple direct drive system. The Minolta is ten years newer then the E-5 and Viewlex had moved on from importing Goto to Minolta. Personally I think Goto just had such a bad experience with Viewlex and the bad added electronics that never seemed to work right, that they terminated the association. Viewlex went belly up sometime in the mid 70's so this is probably one of the last Minolta projectors incorporating Viewlex electronics. It was a totally solid state dimming system that could be controlled by a four track, 8 track type recorder. I did get a maintenance logbook with the projector which was very detailed for a period commencing with procurement in January of 1977 and ending in December of 1991. The electronics started causing problems in April of that year, and the tape system that ran the automation was a headache from May on. The only mention of the projector itself was simple cleaning of slip rings and the occasional bulb replacement. Things got so bad that in November of 1990 they replaced the entire Viewlex control and automation system with a Screenmaster system by Joe Hopkins Engineering. The job took 100 hours over a five day period. Projector maintenance was turned over to Minolta at this time and the log book ended. As I mentioned before, Joe never made any schematic drawing of his changes. Some of the Viewlex electronics was removed from the original Viewlex rack and incorporated into Joe's changes. The automation (Joe's system) was not part of the deal and was basically cut out of the system. Since it all ran on a IBM486 (the computer of the time) and they wanted to keep it for programing. I am assuming that the Minolta/Viewlex electronics are as bad as the Goto/Viewlex ones, so I will not even try to get them working again. Since my plan is to give live shows and not programs like "Larry, Cat in Space", it should be no problem to get the projector up and running very much like the E-5 and A3P before it. I will try and get the exsisting control electronics up and running as I would like to be able to use the controls on the classic control pannel. However, I will not waste a lot of time on it. If problems occur, I will run the machine with a simple direct system and then perhaps play with the old circuits as time permits. Yes, Ron, me too. My STP came with a very nice 3 axis Sky-Skan Spice Automation System Nutmeg 2. There is no documentation or manuals and no computer or software. They recently spent $ 40,000 dollars on the new motors, controller and software. Incidently, I have been playing with the new DC motors today and they run great. Owen Planetarium Projector Museum www.pictorialism.com
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Post by Ron Walker on Sept 7, 2022 11:22:08 GMT -7
Posted by: Owen Phairis Jul 7 2008, 07:41 AM Hi Ron, Say is your Minolta a 2 axis or 3 axis machine? Also, do you have any photographs of the base? Thanks, Owen Planetarium Projector Museum www.pictorialism.com
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Post by Ron Walker on Sept 7, 2022 11:22:44 GMT -7
Posted by: Ron Walker Jul 7 2008, 02:45 PM QUOTE(Owen Phairis @ Jul 7 2008, 07:41 AM) * Hi Ron, Say is your Minolta a 2 axis or 3 axis machine? Also, do you have any photographs of the base? Thanks, Owen Planetarium Projector Museum www.pictorialism.comIt is two axis. There is a projector that projects a 0 to 90 degree scale from horizon to zenith that will rotate around the entire projector allowing one to measure the latitude of any object at any place at ant time. Pictures will follow.
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Post by Ron Walker on Sept 7, 2022 11:23:07 GMT -7
Posted by: Owen Phairis Jul 7 2008, 04:13 PM QUOTE(Ron Walker @ Jul 7 2008, 02:45 PM) * It is two axis. There is a projector that projects a 0 to 90 degree scale from horizon to zenith that will rotate around the entire projector allowing one to measure the latitude of any object at any place at ant time. Pictures will follow.
Thanks Ron,
It certainly has the 'apperaence' of being a 3 axis machine. Personally, I am ok with a 2 axis machine and might actually prefer it. Looking forward to a picture or two of the base. Do you remember how high the lattitude axis was off the floor?
Thanks,
Owen
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Post by Ron Walker on Sept 7, 2022 11:24:15 GMT -7
Posted by: Ron Walker Jul 7 2008, 06:32 PM QUOTE(Owen Phairis @ Jul 7 2008, 04:13 PM) * Thanks Ron,
It certainly has the 'apperaence' of being a 3 axis machine. Personally, I am ok with a 2 axis machine and might actually prefer it. Looking forward to a picture or two of the base. Do you remember how high the lattitude axis was off the floor?
Thanks,
Owen
The school had the projector up on a steel frame base. They put the spring line at 7 feet. With the center support (the unit that holds the projector frame and also the motor for the above mentioned projector) on the ground, the latitude axis is 5 feet. This was a building requirement as I had a 20 foot height limit and actually works for me as I've never liked high spring lines. It always made me think I was looking out of a hole.
I agree about a two axes machine as I will never have classroom seating. Besides, as has been pointed out before, the projector is part of the show and should have center stage. laugh.gif Also I like the idea of using bean-bag chairs so that one can get very comfortable looking up at the sky. Time will tell.
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Post by Ron Walker on Sept 7, 2022 11:28:44 GMT -7
Posted by: Owen Phairis Jul 8 2008, 02:16 AM QUOTE(Ron Walker @ Jul 7 2008, 06:32 PM) * The school had the projector up on a steel frame base. They put the spring line at 7 feet. With the center support (the unit that holds the projector frame and also the motor for the above mentioned projector) on the ground, the latitude axis is 5 feet. This is actually how I plan to set the projector up as I've never liked high spring lines. It always made me think I was looking out of a hole.
I agree about a two axes machine as I will never have classroom seating. Besides, as has been pointed out before, the projector is part of the show and should have center stage. laugh.gif Also I like the idea of using bean-bag chairs so that one can get very comfortable looking up at the sky. Time will tell.
Thanks Ron for the information.
Owen
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Post by Ron Walker on Sept 8, 2022 19:05:04 GMT -7
Posted by: Ron Walker Aug 27 2008, 12:21 PM OK, I'm a nitpicker! There, I've said it, but there are times that I just don't understand how other people think. I have been spending some time cleaning up this projector and have come across two (what I would call common sense) points that I just had to share with everyone. Both are in the planet cage. Looking at the objective lenses I noted an irregular "ring" of about 1/2 inch diameter on the surface. At first I thought this might have been a wear ring in the lens coating do to overzealous cleaning, but then, the rest of the cages appeared not to have been cleaned since instilation. Upon closer inspection I discovered that the "ring" was raised from the surface of the glass and was probably some form of glue. Now why would anyone put a ring of glue on a lens element. All I could think of was to place a filter over the lens to change the color of the projection. But why not put the filter inside where there is plenty of room for a friction fit inside. I guess I might never know. With a little TLC and some soaking time, I was able to remove the offending "glue" and return the several lenses to their original state.
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Post by Ron Walker on Sept 8, 2022 19:08:30 GMT -7
A second problem concerned the Venus projector. There are knurled rings on the back of each projector that are used to access the light bulbs. When a new bulb is inserted it is moved about until the brightest image is formed and then the ring is tightened. The rings on both of the Venus projectors were loose. At first I thought that they just come loose in shipping, however they were the only ones. All the other projectors were tight. I also noted that with these projectors only, a small section of the ring was ground off. If the ring were tightened, this flat area would be off to one side. In my many years on this planet, I have concluded that people and manufactures do things for a reason. Sure enough, upon moving the planets through a few years the knurled knob on the back hit a main gear support. Obviously the reason for the machined flat was to clear this post at this point in the planets cycle. If the knob was loose as when I found it, the projector would just clear and continue on unimpeded. If the knob was not tight however, the bulb would not remain for long centered and provide the best light. At first I thought that it might be a multi thread and the ring only needed to be started at a slightly offset position. This assumption proved faulty, it is a single thread. A simple review of the projector revealed two set screws holding each projector in their frame. A simple rotation of each projector placed the flat at the bottom and allowed the projector to clear when tight. This position was clearly the designers intent and I can't understand why whoever worked on the machine didn't see it. My understanding is that is was serviced by Minolta itself. Certainly they should have known how to adjust this unit.
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Post by Ron Walker on Sept 8, 2022 19:16:21 GMT -7
Posted by: Owen Phairis Aug 27 2008, 12:48 PM Interesting.... Glad to hear you are working on the Minolta, thanks for the pointers! Owen One of my Minolta planet cages before removal.
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