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Post by Ron Walker on Sept 18, 2022 17:21:12 GMT -7
Posted by: moonmagic Sep 12 2013, 06:54 PM I too wish to add my CONGRATULATIONS. The concept and the workmanship is amazing! WOW!
The floor, the plywood form structure, the brickwork, and the ability to control the thickness for the interior finish, all just spectacular.
I once (1974) had a 24 ft. diameter fiberglass (Spitz) dome. Early on we were concerned about the amount of echo, however after carpet was placed on the floor and up 4 feet high onto the walls, there was no noticeable sound issues. mm
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Post by Ron Walker on Sept 18, 2022 17:21:51 GMT -7
Posted by: Ron Walker Nov 13 2013, 05:47 PM Hi Albert, just wondering if there are any new chapters to your planetarium tail. Can't wait to see what has progressed.
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Post by Ron Walker on Sept 18, 2022 17:22:11 GMT -7
Posted by: albert Nov 17 2013, 10:48 AM Dear friends, here are the latest news from the Bad Toelz planetarium! We are almost done.....not entirely but its in the finishing stages. We have the light alcove and the sound dampening ceiling...we are still waiting for the LED lights. Electricity is almost done, as is the air conditioning system. We have reached the conclusion not to fix the chairs to the floor. We will instead mount them in groups of threes onto a wooden board that is curved to follow the curvature of the planetarium wall. This way nothing can fall over but we will stay flexible concerning the chairs. AND we won't risk to drill into the floor heating system... Could not resist and did a test projection in the dome on Saturday. Just the starball again minus the eyelids. The sky looks wonderful and I hope we will be able to get a clear and crisp projection on the dome. Can't wait myself to see the projector finally installed!!! Here is an image of the room just before installation of the ceiling.....the weird curves are a result of the panorama stitching.... under the dome you can see our "chair test" with the wooden board under the chairs. We tried everything to topple them but due to the curvature they are as stable as if they were fixed to the floor.
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Post by Ron Walker on Sept 18, 2022 17:22:30 GMT -7
Posted by: albert Nov 17 2013, 10:50 AM Even now we have diminished the "echo chamber" effect to the point that I don't think it will be a problem. Here is the covered ceiling.
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Post by Ron Walker on Sept 18, 2022 17:22:52 GMT -7
Posted by: albert Nov 17 2013, 11:01 AM Here is the lighting cove still in white, it will be black on the outside and white on the inside of course. The holes are for downward-directed LED spots. I have opted for a controlled, pretty directional lighting situation going down from the spring line, and for totally diffused light going upwards. I think this could look quite spectacular in the end, kind of giving the idea that the dome is resting on beams of light....the light cove is made of wood, so we can add holes or modify things if we want to attach anything to it later.
I have also bought a tiny, pocket book sized "pico projector", the VIVITEK QUMI 5, for the projection of graphics onto the dome while people are coming in, getting adjusted to the low light level. The thing is not exactly silent but the noise is ok, and it has only a few hundred lumens of light output (LED). AND it has not too much stray light coming out of the fan ducts. It has a standard tripod thread on the bottom so I will be able to attach it to one of the ZKP struts with a suitable ball joint. No sense getting a standard beamer with thousands of Lumens only to have to filter them out. The thing STILL is too bright, but there is an "eco-mode"...it remains to be seen if I can use it DURING the show. Probably yes if I fade out the stars and bring up some level of light in the dome to mask the grey frame of the projection.
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Post by Ron Walker on Sept 18, 2022 17:23:10 GMT -7
Posted by: albert Nov 17 2013, 11:09 AM The light control will be by a standard DMX lighting console. I can pre-program fades and the like and I think I might later on put the entire projector control under DMX. This way I could sit in a normal chair with the console on my lap. We have a control console with 48 faders and right now we are using only twelve of them for the house lights and the dome. So there is room for the projector circuits. Right now I have to put everything in the middle right next to the projector, as it can not be controlled from the side. I will also experiment with the position of the loudspeakers. In our first test the most successful position for the speakers was right next to the projector going straight up onto the zenith of the dome. This might change when the chairs and carpet are installed.
Well, that is the state of the "art" right now! Ron, I hope you have also been able to make some progress. I will check into "the dream is alive" now! Mine is more alive than ever!!!!
Cheers to all
Albert
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Post by Ron Walker on Sept 18, 2022 17:23:32 GMT -7
Posted by: Ron Walker Nov 17 2013, 06:11 PM QUOTE(albert @ Nov 17 2013, 11:09 AM) * The light control will be by a standard DMX lighting console. I can pre-program fades and the like and I think I might later on put the entire projector control under DMX. This way I could sit in a normal chair with the console on my lap. We have a control console with 48 faders and right now we are using only twelve of them for the house lights and the dome. So there is room for the projector circuits. Right now I have to put everything in the middle right next to the projector, as it can not be controlled from the side. I will also experiment with the position of the loudspeakers. In our first test the most successful position for the speakers was right next to the projector going straight up onto the zenith of the dome. This might change when the chairs and carpet are installed.
Well, that is the state of the "art" right now! Ron, I hope you have also been able to make some progress. I will check into "the dream is alive" now! Mine is more alive than ever!!!!
Cheers to all
Albert
Things are moving along quite well. It looks like you will be up and running quite soon. I'll have to look into that DMX light control system as I would like to have some automation with the dome. Can you tell me about any automation that they might have. What I would love to have is a device that would lets say dim a light from full to blackout in say ten minutes. Now what would be very handy would be to be able to move the dimmer control to say 20% and the system dim the light down to 20% in eight minutes and then hold at that level until the dimmer control was moved again. Then a simple move down to 0% would give complete blackout in the next two minutes. I would imagine that these types of systems are available but probably extremely expensive.
Congrats on your progress.
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Post by Ron Walker on Sept 18, 2022 17:23:55 GMT -7
Posted by: albert Nov 19 2013, 02:16 AM Hi Ron!
DMX 512 is a "protocol" like MIDI or any other multiplex signals. You can have up to 512 dimmers or moving lights on a single DMX line. Just "daisy chaining" them one behind the other. Each member of the chain will look for its own address and then you can send messages to this member only. Quite clever, just two wires. There is tons of information on the internet for this. A small DMX box can be attached per usb connection to a laptop, and it will create the various signals. That way you can have your own lighting console on the laptop. Even some freeware can do this...so all you have to get is the box and the laptop and a dimmer and you are up and running.We are using a solid state control system though. It is called "SmartFade 2496". The advantage here is that I can have a simulation of this console with all the faders and switches on my PC. I do the program on the PC, save it on SD cards and then the console will run it. Of course manual control is also possible. CAVEAT here: The DMX protocol is quite old, so it is 8 bits. Means you have only 256 discrete "steps" to control the brightness of your light. With LEDS and the typically low light levels in the planetarium these steps become very noticeable, especially on loooong fade times. With incandescents it is not as noticeable, but LEDS have no inertia and so any flicker will be immediately noticeable, like in neon lights, too.What this means is some kind of "ramp" will have to be integrated into the dimmers themselves. Some dimmers can have a delay programmed into them which means they will smooth over these steps according to a curve. I will have to go thru this process and I look forward to the next few weeks as we will build this into the planetarium and tweak it out. R& D time!! I will keep you posted on this! The great advantage of the RGB LED concept is that you can really create beautiful mixed colors of any kind. I tested this out with a cheap 35 Euro LED strip that can be bought almost anywhere. The dome surface just disappears in this soft light. Another question with LEDs is how far can you dim them down? Or will they come on brutally after a moment when the voltage is high enough to make them "fire"? if nothing works I will use the built in blue dome lights on the zkp 1 with their good old variac to make a dead smooth fade out...and use the cove lights only for general illumination. Perhaps mixing these two techniques will do the trick. I guess your minolta machine also has these lights built into it?
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Post by Ron Walker on Sept 18, 2022 17:24:40 GMT -7
Posted by: Ron Walker Nov 19 2013, 01:44 PM Thanks Albert, I need to look into all of these things. Looking forward to your reports. I was going to use LED's on the room and Moon blue lights until I ran into the obvious stepping of the light level at the very dim end where I needed even adjustment more then ever. My experiments on this can be found starting here: www.observatorycentral.com/index.php?s=&showtopic=3403&view=findpost&p=47346I went back to the good old Variac principal so as to get extremely smooth fades from full on to full off. However, so much happens at sunset/sunrise that it would be nice to have a little automation. We have stars and planets up. Daylight and Moonlight down. At the same time sunset/sunrise glow as well as twilight glow goes up and down. A lot to turn while still speaking comprehensively. But then, with the right music, sunrise/sunset can be stretched out into something quite beautiful. Anyway, looking forward to you experiments and results.
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Post by Ron Walker on Sept 18, 2022 17:24:59 GMT -7
Posted by: albert Nov 20 2013, 02:31 AM Hi Ron, Interesting to note that you've been there before....and found no other solution than the old variac. I will try to push for an electronic solution, since the manufacturer of the dimmers we are going to use sits right in Bad Tölz across the street from the planetarium. We will see if they can come up with a solution. Another problem I have noticed with my first test is that the horizon line will be too bright and the rest of the dome too dark. I think we could also come up with a way to put some high end LEDS into the luminaries included with the Zeiss machine. This way the light will come from the center of the dome and be much more diffused. Or a mix of the two.The light from the 50 Watt star lamp is really weak so this will push us to the lower end of the dimmer's range in all cases....not something one usually runs into....BTW do you have a drawn schematic or a tooth count and gear scheme of the planet projectors? I am toying with the idea of making a demonstration model of a mars projector. I use a 3d printer at the moment to make a similar model of some gears of the Antikythera mechanism since I will have a presentation on that. I always find some hands on experience is great and not just showing a bunch of slides....
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Post by Ron Walker on Sept 18, 2022 17:25:18 GMT -7
Posted by: Ron Walker Nov 20 2013, 09:37 AM They may have 24 bit controllers and they might work better but are much more expensive. On virtually all of the projectors that I have seen, both the sunrise/sunset and twilight glow are projected by brute force projectors from the center of the room. The effect is much more subtle then from the cove area, at least as I see it. I will take some pictures and post.
I never got any schematics on any of the mechanical components but I guess I could try and count them.
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Post by Ron Walker on Sept 18, 2022 17:25:41 GMT -7
Posted by: albert Jan 4 2014, 04:12 AM Dear Friends! I am happy to report that my new planetarium is almost finished! We had a very busy December...doing almost 50 shows in the marionette theater...and between shows there was a lot of work and decision making to be done downstairs in the planetarium. I got the machine installed in the dome on December 6. What a moment to see the stars for the first time! Meanwhile I got most of the settings correct and we are busy putting in the chairs which come from a cinema in Munich that closed down several years ago, I was able to get 213 chairs. 100 of them we installed in the marionette theater and the rest went into storage until now. And now please follow me to see the progress.... First test of chair mechanisms in the round. We decided to NOT attach the chairs to the planetarium floor at all. Instead they are mounted onto wooden boards either in groups of three or in groups of 2. Due to the circular form of the wooden boards the chairs cannot fall over. We also attached them to each other but this way the entire seating can be removed if necessary. I have a second row of chairs that will be installed as well. Total capacity will be 35 seats. If necessary the second row of seats can be taken out and kids can sit on the floor. The auditorium can also be opened up if we want to have lets say a wedding under the dome...we just remove the seats under the open part of the dome and this way people can either stand under the dome or sit down. The shot was taken with the blue LED lights on in the cove.
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Post by Ron Walker on Sept 18, 2022 17:26:02 GMT -7
Posted by: albert Jan 4 2014, 04:18 AM The lower part of the projector was also installed at this test. I had the idea to put the spring line at 2.1o meters instead of the Zeiss specified 2.05 meters. This will leave room for a platform with casters under the projector. For the moment the projector is non-removable though since I did not have time to get the caster platform done. It is only a matter of a few hours to dismantle the projector. If we want to make it removable this can be done quickly. Voilà the finished auditorium...minus the second row. The lighting cove is made entirely of wood.- painted black. Every 80 cms there is a LED downlight which gives the dome a very spacey look indeed.
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Post by Ron Walker on Sept 18, 2022 17:26:21 GMT -7
Posted by: albert Jan 4 2014, 04:22 AM I had to decide how deep to make the lighting cove and 20 cms turned out to be just right. The LED modules are not attached in any way-they just lie inside the cove. Here some pix taken during the installation of the projector. the central post with the heavy transformers and the switchboard comes out of storage.
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Post by Ron Walker on Sept 18, 2022 17:26:44 GMT -7
Posted by: albert Jan 4 2014, 04:26 AM 31 eyelids are prepared to go back onto the starball... I had done a preliminary test a few days before this...just the starball supported on my electricians ladder and attached to a 12 volt power supply. Of course the result was not entirely convincing as the starball has these ventilation holes which will cause blobs of stray light on the dome without the eyelids in place. So my hands really trembled as I was putting the lids in...I could hardly slow down enough to shoot these photographs.
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