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> Fun Planetarium Facts From Every Epoch
Ron Walker
post Jan 16 2007, 06:09 PM
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We started to get nostalgic over at "Links to Planetarium Projectors" so I though it might be interesting to open a thread about the history and development of the planetarium projector and some of its many incarnations. This will not be in any order but if an interesting find is found, this is the place to put it.

My first offering is a variation on the original Spitz Jr. While the original Spitz Jr. was considered a toy by most, no one could dismiss its value as a teaching tool.

One company developed an expanded Spitz Jr. for use by schools and added the one element that the original was really lacking and that was a dome to project upon.

(IMG:http://img412.imageshack.us/img412/6103/spitzjrexpandedzn6.jpg)

Not at all sure how many of these were ever produced but it certainly was an inexpensive way in for schools.
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mrgare5050
post Jan 26 2007, 03:37 PM
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dang it ron, ive never seen a junior with the dome OR the meridian projector before!
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Ron Walker
post Jan 26 2007, 03:53 PM
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Kind of fun finding these gems. When I was experience my first wave of "planetariumitious" (back in my teens) I saved everything I could find (especially with pictures) so I could build my planetarium with the least problems. This always looked like something that was easy to do. I would , however, have put the meridian projector lower and to the right of the projector base. That way it wouldn't shadow part to the southern sky.
and it would probably be more stable.
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mrgare5050
post Jan 30 2007, 04:41 AM
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it just shows though that you cannot necessarily say.. oh i have 2 of those, like i have been doing, only to find that the juniors differed, had different accessories, we know they were different colors (the yellow base one has a beautiful blue globe)... gare
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Ron Walker
post Jan 30 2007, 12:42 PM
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That's the kind that I had and used for my early planetarium star ball. It is a blue ball with a yellow base and was designed to work on batteries.

I'll try and get some more pictures of my early work up soon.

My biggest problem is that the large "rubber band" that was used to hold the two halves of the star ball together, just disintegrated while it was in storage. Had to get out the old "hot glue gun" to put it back together for pictures.
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mrgare5050
post Jan 30 2007, 07:19 PM
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thats the same thing that happened to my sky zoo, its why you see it in two pieces on my website. i think ive seen juniors advertised as 'nova's also, possibly on pielocks site. wouldnt it be cool to see sales numbers for the spitz junior by year? if you still have your box, they are works of art in themselves. ron did you soup yours up? it really reaaly bugs me we no longer have a cheap source of lenses, what would lenses a junior do? gare
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Ron Walker
post Feb 9 2007, 01:57 PM
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The biggest problem with the Spitz Jr. is that the star ball is too small. Just mounting lenses would take up a lot of real estate and cover some of the smaller star holes. Also you can make the pin holes just so small before you run into projection problems. One of the reasons the Spitz Jr. only projected 400 stars is that there were problems with hole size and the distance from the star lamp. I really think you need to get to a diameter of 10 inches or more it be able to make a real sky. It appears that 15 to 20 inches is a good compromise. With a very small light source, a very good sky can be produced. I might try a "Stinger" bulb in mine just to see if that works better with the Spitz Jr..

I will say that the Streamlight "Stinger" bulb is the best bulb that I've come across for a star ball light source. This Xenon bulb runs at 3.7 volts and consumes 6 watts of power producing 125 lumen's of light. It retails for around $7 on the web. The Goto bulb is slightly better but it cost of $30 is a bit higher.

Using a small arc lamp makes for really fantastic looking stars but the cost is very steep. Actually I never did a cost per hour evaluation, so here goes. The Stinger bulb is rated for 30 hours and at $7 that boils down to a running cost of $0.24 cents per hour. I'm told the arc bulb runs about $700 and is good for 1000 hours costing $0.70 cents per hour. It all boils down too what you want the sky to look like and what your willing to spend. At $0.70 cents per hour the arc lamp isn't bad at all, but you have to buy it 1000 hours at a time. I'm going to check into it soon and can get you final price. Unfortunately Spitz is the only one that has a arc bulb that's bent so to provide a 180* unblocked view of the arc. Such is life.
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mrgare5050
post Nov 6 2014, 05:22 AM
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Gare
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The biggest problem with the Spitz Jr. is that the star ball is too small. Just mounting lenses would take up a lot of real estate and cover some of the smaller star holes. Also you can make the pin holes just so small before you run into projection problems. One of the reasons the Spitz Jr. only projected 400 stars is that there were problems with hole size and the distance from the star lamp. I really think you need to get to a diameter of 10 inches or more it be able to make a real sky. It appears that 15 to 20 inches is a good compromise. With a very small light source, a very good sky can be produced. I might try a "Stinger" bulb in mine just to see if that works better with the Spitz Jr.


Heres a topic from 2007 thats back in my court - Im somewhat obsessed with 'souping up' one of my Spitz Junior starballs - all the problems mentioned above by RW of course seem daunting ....
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Ron Walker
post Nov 6 2014, 09:58 AM
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Someplace I talked more about replacement bulbs and there was a small direct replacement (voltage and current wise) that Worked really well. The Stinger was better but you needed to change the power supply.

I note that there are blank photos from back in the day when pictures were posted elsewhere. That is a job to do, find all of the blank missing pictures and replace them so the image is again available.

Who out there has the time to make up that list?
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