Albert...ZKP 1 found and taken home....

Posted by: moonmagic Jul 23 2009, 11:43 AM
Albert-Allow me to add my CONGRATULATIONS on your WONDERFUL find. It is a great machine and we all wish you luck in finding a dome for it. The fact that you had it up and working in a short time is amazing. There are many of us still waiting and hoping to find our first machine of any type, make or model, but a Zeiss projector WAS the one that THUS FAR had eluded everyone on this forum, as far as I know. This is no longer the case, you are the first!

I think this now entitles you to do the official "Happy Dance."

I too will be looking forward to your next reports and pictures.

mm

Posted by: albert Jul 25 2009, 07:09 AM
Thank you all again for the wonderful reactions to my article! I really don't think I would have tried this without your example.

Ron I think you may be right about the grease in the motor. I will look into this next week, if I can find the time.

I have already done some shooting in 3D and sent the pictures to Owen for his museum site.



Meanwhile I have completed the setup and mounted the horizontal ring bearing a small projector for projection of a moveable vertical circle. The milky way projector was also tried on but removed again because it contains liquid mercury as horizon cutoff. I don't want to have this around the house. The milky way film seems a little bleached out but there is a rheostat on the switchboard to regulate the intensity of the lamp. the way it is set up the lamp runs at maybe half its nominal power.
The depth of field of the Tessar lenses is amazing. I think this machine could work in domes from 9 to 20 ft diameter which would make it really well suited for a small private planetarium. The lenses are about the size of a fingernail.

Posted by: Owen Phairis Jul 31 2009, 05:50 PM
I did some very quick calculations out of curiosity. The starfields have to cover 11,310 square feet on a 30 foot sphere and 20,106 square feet on a 40 foot sphere. That is close to double, I find that interesting. Now, to calculate the difference in lenses that would be required.....
Of course, if you were painting the planetarium dome you would obviously have to divide the projection area by 2 to get the square footage to know how much paint to purchase for the dome.

Owen -

Posted by: Ron Walker Aug 4 2009, 10:04 AM
QUOTE(albert @ Aug 4 2009, 02:46 AM) *
Hi Owen,

I'm on holiday in France at the moment and it took me a while to get access to an internet connection.

Of course you are right about the beam spread. I can see the borders or limits of the projectors on my ceiling which is about 3 ft from the top of the starball. But from about 6 ft on these are gone. My farthest corner of the room is about 20 ft away from the machine. I can see the constellations normally, although some of them are projected by 2 different projectors. Orion has its two lowest stars on one projector and the rest is on the projector adjacent to it. So its very difficult to determine what would work in a dome or at least still be tolerable.
Dust problems: On looking very closely at the projection I have found that some projectors-presumably those that were on top of the starball during its 17 years of mothballing- seem to have dust on the star plates or on the glass that the plates might be framed in. On of the big dipper stars looks very mushy. The lenses are clean so it must be on the star plate directly, the condensers look good to me, too.
I am really worried about having to dismantle the projectors...I think about maybe getting the lenses out and using air to get rid of the dust. Any ideas or advice about this? Ron you might know more about this too since you have progressed to the star plates in your Minolta. The Zeiss documents say that the projectors are basically dust proof and should not be dismantled.
Another problem that might come up is the fact that if the machine is in a room with windows, the Sunlight might fall into one of the lenses of the starball and burn holes into the star plates. I have the machine covered when I take the shutters off the windows.

I will publish some more pictures as soon as I have the time. I took a lot of detail pics most of them in stereo. Can I publish side by side stereos here?

I have found the star plates on all of the projectors to be in excellent shape and very clean. The only accumulated dirt and grime has been on the outer lens and outer condenser surfaces and easily cleaned. Since it is only one star in the big dipper that looks out of focus, I am wondering if the Zeiss uses a system similar to the Minolta (or perhaps it is the other way around wink.gif ) and the small auxiliary lens has shifted or somehow been dislodged.

Knowing German engineering, I can't imagine any problem with dismantling and reassembly of the projector. Just go slow and don't force anything. As far as the Minolta, everything came apart with just hand torque.

Interesting thought with the Sunlight issue. The projectors would act like cameras in that case. I guess it would dpend on what the star plates were made out of. The fact that the lenses are probably set at about 3 to 4 meters would put the Sun, at infinity, out of focus and thus less of a threat, but then why take chances with the projector.