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Post by starsheep on Feb 26, 2024 0:01:41 GMT -7
It is curious how one thing leads to another.
Also how online searching works or does not work. When I got the planetarium toys at the start of the month I did a lot of mad googling (Or is it giggling.) Mostly All I could find was sales listings. Many seem to feel the need to monetize what ever they can. A lot of collectors seem to have been for investment. Which does not really work in a non linear system.
I kept fiddling search terms till Google wanted to know if I was a robot.
I did stumble across some interesting things. A site called cloudy nights lead me here. I skimmed both sites. Finally landing here as it looked like there might be a bit of activity. It also has good technical info. Getting the STL models was exactly what I was looking for. It is amazing just how many different planetaria have been constructed in the last century.
Studying the STL files of the Spitz A. I quickly came up with quite a few internal questions and observations. The first was how do the planet projectors work? Of course I could simply ask in that thread. First though I wanted to see what info was available. I thought perhaps I could do a site search here using google. This often works better than the internal board search. There seems to be a lot of info here. I only know some basics (to be dangerous.) Google however does not seem to have this site indexed. Possibly as the search term 'Spitz "A" planet projector" is a bit generic. No results were returned. Not sure if there is a way to open this out, but if searches do not return content here, how can anyone respond to it. I am not really complaining here, more observing. In an ideal world, I would expect the technical hits to come up in the front of the search.
Somehow, Perhaps it is that I am re-reading the Henry king book. I thought I would add the term Orrery. Since the planet projectors work on much the same principle. This lead me back to cloudy nights and a thread that seems to be by our own Ron Walker using toilet paper tubes and plywood. I had read this thread early on without comprehension. Now it made a lot more sense.
I was also returned to the Planetarium museum, where I had downloaded 3D images of the model "A" projector. I probably should load the STL files into my cad program and assemble it there to see how the parts fit together. Again things make much better sense now.
The other thing was I started getting literature results. A sketchy site seemed to be offering up a PDF of the A3P manual. I hate that scam, as my searches for the Kodak pcd scanner do this as well. Some of these can be quite sophisticated. Making it look like the manual you want is behind a paywall. A cache search usually shows it is simply your search terms blurred back. In this case it did look like there was a real document. So I took a chance in a private browsing window, with redirects turned off. Sure enough there was a real PDF. Now why did it take a month of searching to find something like this? There was also blog posts from the Academy of Science, defending their scrapping of the Morrison projector. (and a rebuttal.) I may not be the only one boycotting this institution over the destruction of a beloved past. The 50 buck admission fee does not help (They think they are in the same league as Disneyland.) I could buy a nice junk watch to restore for that, and the gas and bridge toll saved pays the eBay fees and taxes.
Somewhere in all the noise, I found something that said that the planet projectors on the early Spitz instruments were manually set. Which in a lot of ways makes sense. I really know nothing about these things. It never occurred to me that they weighed tons. That moving them takes a crane. This got me thinking about what I find fascinating with such devices.
Once I hit upon a more literary search, the results started to deal with the fancy modern digital shows. What I liked about the old Skool stuff was the simplicity. In some ways Owen Pharis' museum makes me sad. With all the projectors clumped together, like the estate sale I went to with boxes of projectors stacked meters high on a folding table. It is great that they are 'saved.' But without the domes they are no more than 'art projects.' Perhaps there is a bit of envy here. I used to dream of finding a projector in a junk store. Well I still do. I think it has been a dream for over 50 years.
Giggle also started turning up patent documents. It is amazing how, the industry direction demanded more and more stars and more and more complexity. I personally like the idea of lesser stars, but I like the armrillery rings especially when projected and presented in that beautiful 18th century copper plate script.
Back in the day, I got a simple Apple ][ program. It plots I think perhaps 150 or so stars. And the planets. In college I had a table of many more, which were in a file called NasaStars. I lost this, then found it again. Along with a bunch of FORTRAN programs for calculating planetary motions. I can still remember typing in the Apple ][ program. I still have the broken book, with handwritten lines where I checked off each number. As noted in my intro, I converted this program to C and postscript. I made it so the could use both sets of data. And plot it as a flat perspective.
The author claimed the program was well documented with REM statements. And in a way it was -- provided one was learning how to write programs back in the 1980s. The key function which contains the planetary elements is barely documented at all. The same function is written different ways. The program seems to have been stitched together from the other examples. I still do not know what the orbital elements are. They do somehow lead to producing heliocentric longitude, Right Ascension and declination. As far as I can tell they are based on epoch 1960 as the number of days since that mark are computed. In some ways it would be nice to know what the terms actually are. And what the Epoch 2000 or even Epoch 2030 might be?
Sure I can download fancy programs on my phone which use the internal GPS and will tell me exactly where Canopus (one of my favorite stars) is at the moment. These thing though are flat screens. People like flat screens. It seems most planetariums are now basically theaters what show science documentaries. It is ironic how the modern world tells us sitting outside under an open fire, watching the stars, is bad for the environment. Many used to see pictures in the flames and patterns in the sky. Now we have the digital fireplace. I wonder what Plato would have made of that. In some ways the virtual world reflects back the shadows of this world into an abstraction which is closer to the object, than the object we actually see.
I do think there is still a desire for the sort of entertainment a simple pinhole projector provides. Especially when it can show the invisible lines of the clockwork dials. One of the other literary results was for a book "Theater of time and Space" By Marché. Google books lets one read the introduction and preface. I do not think there is anything technical in it. Seems more like the King book in dealing with the sociology of planetariums. It did prompt me to come back here and write these musings.
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Post by Ron Walker on Feb 26, 2024 11:18:09 GMT -7
I love it when I read someone's thoughts and they agree with mine. Not that it will change the course of history but it at least allows me to think I'm not alone in my madness. First I must agree with you on the deteriorated state of the planetarium. Going digital was bad enough under a dome as it was in movies and audio recording. The "planetarium at ASU is indeed a flat screen with projections controlled by a computer. They do present in 3D but half the audience doesn't bother with the glasses, but I guess they are "entertained" enough without them. After all, laser shows are the best part of a planetarium, aren't they?
There was something special and "rounded" with the old analog way of things. It was more of an art form, not the angular presentation of ones and zeros. It is interesting that many of these old analog ways are coming back, supported by people who can afford to bring things back. New is not always better as analog film, tape, and records attest too. Do they have flaws, everything has flaws, but they bring that "roundness". After all, we are analog beings in an analog world and while digital might be more accurate, it might not be as pleasing.
I find it very interesting that the younger set (who probably were dragged to one of my shows) went out of their way to thank me for the show. Many thought they were going to see a movie with Big Bird talking down to them. The thing I tend to forget is that most had never seen a true analog planetarium show. They were amazed not only by an accurate presentation of the night sky but also by that device from Mars that occupies the center of the room. If one has never seen a thing, that thing is new, even if it is technically old.
As to Owen's collection. It is indeed one of the largest and best collections in the world. One of the fundamental differences between Owen's philosophy and mine (and apparently yours) is Owen thinks the various machines should remain a static exhibit, while I believe they should be a working viewable one. I had envisioned a dome with a floor similar to a railroad turntable where each machine could be moved to the center and become operable. N9ow this is indeed a grandiose idea and admittedly an expensive one. Perhaps this disagreement is why he no longer participates in this forum. Perhaps it was something I said but for the life of me I can't think of what it was or could be. I know Owen has tried to put together a traveling exhibit to go from planetarium to planetarium but even in this centennial of the optical mechanical projector, there appears to be no interest. It always boils down too money, and the logistics of such an exhibit would be mind blowing. When people ask about my projector (and someone in each show always does), I mention that he is the brother of the star (projector) in "LaLaLand").
The big problem is that for most of the people in the planetarium profession, it is a job. The number of us that truly love these magical machines is less then we tend to imagine, but is reflected in the number of participants. As with the old web site, there are only a handful of posters which I think is the nature of the beast. Many of the joiners have never participated since they joined. Perhaps because we are not professionals.
As to make this site more visible, your guess is as good as mine. I have done everything I can do other then throw money (which I don't have) at it, but I doubt that would help much. I find that whenever there is any thread activity there is an uptick in the number of visitors, usually over two hundred or so. The problem is that without participation this site will drop further back in the search engines and I tend to doubt the providers of this free board will do a whole lot to push it along. After all, they have thousands of freebee boards and they very probably want them to become paying boards or at least have enough activity that the ads are presented to a worthwhile number of people.
If you have gone this far with me I can tell you that the Spitz A, A2, A3, and Zeiss ZKP1 all relied on hand setting of the Sun, Moon, and the five naked eye planets. I'm sure that without computers they all had subscriptions to the Ephemeris to find the locations for any give day. While the Zeiss had mechanical gearing for all of these objects since day one, Spitz joined the ranks with the introduction of the A3P projector.
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Post by starsheep on Mar 4, 2024 18:01:45 GMT -7
This section is as good as any for stream of conscience type musings.
I have been meaning to reply to th is for the last week or so. Been working on some pipe organ projects.
I also had a request for a 25+ year old article on piano roll scanning. No one could locate the author. I had mentioned that way of working in the lecture I gave in Switzerland in 2022. For some reason the webmaster wanted to contact me through a 30 year old email address! (well it dates to 1996.)
I found my main backup drive had the click of death when used on this computer which only has USB 2.0 The drive has firewire, so I tried that and it worked. The file was on that backup drive. Most of the stuff I have is either on a computer, flash drive or CD. Not that I have easy ways of reading a CD without tracking down the external reader. Interesting that it was only this one file I could not find. Everything else seems to be on the backups. Of course backups mostly contain outdated version of old programs which are not supported on newer hardware. Often on can find an emulator. Especially for the old DOS and Mac OS 6 through 9 stuff. I have a collection of vintage computers I use.
What was interesting I found I had archived a bunch of stuff from sci.astro.planetarium on the old USENET network. Giggle is supposed to have this stuff archived as they took over USENET.
My interest in planetariums goes back a long way.
Since I had the old G4 laptop open to look for the file I tried running my CAD program. I was able to import some the spitz stl files. One thing that the modern preview on the mac does not show is the scale of the parts relative to each other. This makes the assembly much easier.
The thing with the CAD program is that it tends to take as much time to import, position, and assemble the objects as it would to assemble a model in the real world. The CAD though has the advantage of being able to turn sections on and off.
Amazing how well this 20 some year old software works. Nowadays they want you to rent it by the month. Which makes sense in a modern sort of way. Still I paid a lot for this program back in the day. In theory according to the salesperson I should be using it to make 100,000 of dollars in productivity. Ha! They have no idea that some people use such things for a hobby. That I can go years or even decades between projects.
I bought this program to layout orrerys and astrolabes. I still have the files on the G4. Interesting to look at them after all these years. Back then I did not have laser cutting and 3D fabrication. Even now such things are still a bit crude for the work I am interested in.
The program is for solid modeling, so the STL files show up as a mesh. I was thinking more along the lines of a gcode plot for the drill centers which is what the laser tools want. I suspect for the star ball, the best way to program such would be through the postscript using the old data I have.
The other issue with CAD programs, is they can have a steep learning curve. So unless one is using it regularly one has to refresh how it works. Mostly I can open up the old files, move them around and view things. Actual editing will take some practice again.
I also feel a bit like a kid in a candy store. The STL models are what I have been wanting. It does feel good to have them to play with, as they can for a baseline for the projector I really want which is a combination of many things.
So it is a start or in this case restart.
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Post by Ron Walker on Mar 5, 2024 10:05:44 GMT -7
I have computers going back before windows and not at all sure if any of them work any longer. I have several XP units that I still use regularly because some of my older programs only work on them and I hopefully will never buy a program that I have to buy every month. I even have a windows 2000 program that I use every month. Some of the earliest material from the original of this blog is on computer drives that joined the internet with phone lines at 300 baud. Someone actually asked me for some material (a new year counter for the Goto E-5 projector) which I made some years ago, but I have no idea where it is and would need to go through many of those old computer drives (it they even turn anymore) to find it. Perhaps something to do on a hot summer's day.
CD's are a much better storage medium then floppy drives (and they hold a lot more information, like the some 20K digital pictures I've taken since my first digital camera from over twenty years ago. I think a better chance with them then the hard drives of the time. I wonder if I'll ever be able to play many of the 3/4" video tapes I used during the 90's.
Perhaps I complain/protest too much, but when I worked with film the equipment I started collecting and using in the late 60's worked perfectly well into the 2,000's when I was literally forced into video by clients. Then I found it necessary to replace everything from cameras to editing bays every three years to keep up with the industry. Unfortunately, that was my profit margin and so I just retired at sixty-two and started wasting time and money on planetariums. The rest (as they say) is history.
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Post by starsheep on Mar 21, 2024 15:52:06 GMT -7
Been pretty quiet here lately. I have mostly been focused on pipe organ stuff.
A few weeks back a pipe organ company I briefly worked for (while the lead installer was on medical leave) Had an open house. Saw my friend who used to Volunteer at the Cal Acadamy of Science.
Mentioned my renewed (Did it ever go away?) interest in planetariums. He noted that they gave him a copy of the plans for the Morrison projector. I asked if he would be willing to part with them. The guy like many of us is a bit of a horder with many 'someday' projects. The reply was "When I am dead." I asked him if he still was planning to make a copy. The reply was "I may."
Someone else entered the conversation, which then turned to the way the star fields were made with grains of sand. (He said carborundum.) Still Aluminum oxide. (sand probably has more silicon dioxide in it.) There was a bit of discussion about the backrooms and basements which few see.
Like me he has not been back since they tore the building down to a single wall and turned it into a disney theme park attraction.
I did download the instruction manual for the Elegoo (last two letters are printed as an infinity symbol) 3D resin printer. Looks promising. May have to get some consumables. May be a fairly messy process. I did notice that there was an air filter inside the main cabinet. What looked like resin in a shopping bacg behind it, And a plastic tray with some other accessories in it.
Hopefully I can find some time to test it. And I know what STL files I would use to test.
I also found my backup drive what had the click of death still works via the fire wire port on an older computer. I guess my main computer is too new. Probably pulls too much power for the USB "c" ports to handle. Annoying how so much stuff is obsoleted in the name of business profits.
My friend did tell how they let him drive the planetarium one day. He said he got it all twisted up in 50,000 years into the southern hemisphere.
Not sure I would ever want something that large. I actually find the Spitz Jr to be quite fun. If only it had clockwork planets ...
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Post by Ron Walker on Mar 22, 2024 16:45:10 GMT -7
Once stricken with planetariumitus, your stricken for life. It might go dormant from time to time but it always comes back.
They did use Carborundum particles as they were available in pre determined sizes making for less problems in placing the stars.
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Post by starsheep on Mar 24, 2024 17:26:29 GMT -7
Sandpaper comes in defined grit sizes.
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Post by Ron Walker on Mar 25, 2024 13:26:17 GMT -7
As well as sand for sandblasting. Only those people directly involved will know for sure. I can only rely on material found in the booklet from the California Academy Of Sciences (that might be considered almost contradictory), "Carborundum crystals rather then sand, however, were chosen for this purpose as they are obtainable in a variety of sizes" and then this quote, "A dissecting microscope was used to sort carborundum grains according to size and shape".
Who knows, there might have been a problem with the sand when the aluminum was deposited over it.
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Post by Ron Walker on Mar 25, 2024 13:50:00 GMT -7
The Spitz Jr. is actually one of the best small planetariums out there (at least in my humble opinion), and works well under a dome as well as four walls and a ceiling. I used one in my early (high school) attempts to build a planetarium. Perhaps the only disadvantages might be the projection of only 400 stars and fourth magnitude not looking much dimmer then first magnitude. But as a basic teaching tool, it can't be beat.  |
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Post by starsheep on Mar 25, 2024 14:18:24 GMT -7
Carborindum as I recall is aluminum oxide. Aka transparent aluminum, also known as sapphire. If colored it is ruby and emerald.
Glass is slicon dioxide.
Sandblasting sand comes from a beach next to the Santa Cruze boardwalk. Shipped all over the world. Quite controversial. Of course it gest sifted. The results are sold at Home Depot.
One of my friends (in the science fiction and costuming club.) built the thin film depositing machines for IBM. (The stuff that coats hard disks.) Little known trivia is that the first hard drives were coated with the iron based paint primer used on the Golden Gate brige. He said internally the stuff (which does not use quantum tunneling.) Is known internally as 'Fairy dust.' It does however control magnetic spin.
My mentor (and family relations) worked in the vacuum tube industry of the silicon valley. So I know the abstraction of it. The filament of the tube gives of metallic ions. If you look at old tubes this can be seen on the envelope surface. In some ways a bad thing, other ways it was done intentionally. My mentor worked with Cliff Garner who was the co-inventor of television in the 1920s. (Philo T. Farnsworth's brother in law.)
The text you post above is also quoted in the Henry C. King book. I am also told IBM cards were used to place the grains.
Not sure what the vapor coating was. It could be any metal. I wonder if the process was an accident from the optical work done.
It sometimes amazes me how simple some of this stuff is. The main requirement is a clean room or box and positive airflow. So I suspect the process may have been discovered by accident when coatings landed on the glass. There were amazing mosaics in the rooms where the women worked. It is unknown it they survived the disneyfication of the museum.
Of course this was all secret WWII work. So there will be a lot of obfuscation. intentional and otherwise. I suspect some of it could also be dangerous. The chemicals and solvents are not nice things. The founder of the clock club Dr Stephans and one of the academy graybeards in the early days was originally a crystal collector. During the depression people traded things like high value watches for dental and medical care. I think the older members who were alive in the 40s and 50s knew him. He let them play with stuff which is now worth millions as children.
So it is easy for people to get a sort of magical thinking way of filling in the blanks. That there must be some sort of difficult understanding in how things like crystals grow. Gas vapor process and such.
On the other hand with 3d printers and the microcontrollers what operate them, It would not be too difficault to make something that could heat up a wire in a vacuum. These of course used to be called light bulbs. 90 some percent of the energy is infrared so they have been banned. (and can burn fingers.) Television tubes worked on similar principles. It all comes down to choosing the right wire.
Does make one consider that the center illumination of the projector is a light bulb. So a lot of the energy inside the star ball is heat.
Chips of course are made from pure silicon, which is also grown through vapor deposition. The first generation stuff was basically put onto the pure wafers with printing presses. (the same offset lithography used to print the church bazaar flyer.) And probably the booklet quoted. Bismuth, which is tar was the resist we used in the jewelry classes. It can be light sensitive as I think it is organic. The Egyptians, may have had the technology for photo etching. Stenciling was defiantly done.
As noted one of my other obsessions is watches. Restoring watch dials is next to impossible. I spend years (30 years ago) before putting these projects on hold. Now with such things as fiber lasers and resin printers, I am finding a renewed interest in this stuff. So it really is a printing process.
I think all the people who were directly involved are gone, Or do not care other than the paycheck or retirement dividend. There are also strange ideas about the ownership of the ideas used to create these processes. We still use the icon of a thermal lightbulb for inspiration. (a myth.)
On the other hand this quote regarding the sorting of the grains, is what made me (when I first heard of it some 30 40 years back) to want to see if I could do it for myself.
At least I found a few others who are as interested in this as I am.
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Post by Ron Walker on Mar 26, 2024 13:09:24 GMT -7
The vapor coating was aluminum. I'm not a chemist but I wonder if sand might have floated up as the aluminum was deposited while the Carborundum just attached to the coating. They later just brushed it off.
Speaking of dust, they had that problem as well, making for a lot of fake stars. They answered that problem by spray painting with opaque black lacquer. Since that covered the proper stars as well, they had to go back and remove the paint from those positions.
Yes, IBM cards were used to generate not only the position but magnitude of the some 3,800 stars projected. The cards were then separated into each of the 32 star plates required for the entire sky.
Yes, the star balls do get hot. My Minolta uses 500 watt bulbs and the 1/4 inch thick aluminum stars balls do heat up even with forced air cooling. That is only 31.25 watts per projector.
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