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DatahopaForumGeneral CategoryGeneral Discussion2 weeks till the eclipse!



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2 weeks till the eclipse!

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Offline DaveMorton Topic starter
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Comfort the Disturbed! Disturb the Comfortable!

As many of you know, I'm holding an eclipse party on the 19th of this month, to watch the annular eclipse that will be occurring in my "neck of the woods". One of the things I'm planning on doing is constructing a "pinhole projector", to display an image of the eclipse in real time, since I don't have such fancy equipment as solar telescopes or even welding goggles (not a good idea to use anyway, since that's not what they're designed for). In doing some research on the optimal dimensions for the projector, I stopped at the proper Wiki entry to find out things such as pinhole diameter and focal length. I bring this up because while I was on the wiki page, I ran across this statement:

Quote from: Wikipedia
NASA (via the NASA Institute for Advanced Concepts) has funded initial research into the New Worlds Mission project, which proposes to use a pinhole camera with a diameter of 10 m and focus length of 200,000 km to image earth sized planets in other star systems.

And I began to wonder... In what universe is 10 meters considered a pinhole?!?!?! Shocked Undecided And where the heck are they going to set something like that up??? Isn't 200 thousand kilometers just over half the distance to the moon?   o.O
Posted May 05, 2012, 06:56:09 AM Logged
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Offline Diesel
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It's entirely up to you Dave, but I think you may want to scale that down some.  lol
Posted May 05, 2012, 11:17:25 AM Logged
It WILL be fine !...

Offline Diesel
England Posts: 1052
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Found this Dave if it's of any use.


http://www.kodak.com/ek/US/en/Pinhole_Camera.htm
Posted May 05, 2012, 11:33:02 AM Logged
It WILL be fine !...

Offline Data
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Where are you going to find a pin to make a 10 meter hole scratch-head, that’s nuts  lol

But I found a page that tells you how to make a Pinhole Projector for such occasions.

http://www.exploratorium.edu/eclipse/how.html
Posted May 05, 2012, 11:42:29 AM Logged

Online Snowcrash
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One of the best 'kitchen science' ways of observing an eclispe (especially if annular) is with a collinder and a bucket of water.

The bucket of water gives you a viewing area and the collinder has multiple 'pin-hole' cameras giving multiple images on the water's surface. The collinder MUST have round holes of equal-ish diameter.

A pin hole camera, with a white sheet of paper to view the image, works well too.
Posted May 07, 2012, 15:54:07 PM Logged
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Offline DaveMorton Topic starter
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I've been performing some experiments in the back yard, and I'm finding that imaging the sun projector-style through a tiny hole simply isn't bright enough, nor is the resulting image all that large (less than a half inch at six feet), so on to plan B, which is to take a small, weak magnifying glass and use it as the objective lens of the projector. The idea isn't to focus the light into a point, but to create an image of the sun that's the same diameter of the glass, which should (presumably) put the resulting image at best focus. The results are quite satisfying; the focal length has dropped from six feet to less than 2, and the image has increased from a half inch to two inches. It's a bright and clear enough image to see sunspots (at least I THINK that's what I'm seeing), so I'm happy with it. I just need to build the box to hold it, and contrive a way to aim the device. I may also ramp up the size of the magnifying glass in order to get a bigger, brighter picture. Smiley
Posted May 07, 2012, 17:19:25 PM Logged
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Offline sybershot
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Glad to hear you got a working prototype Smiley be careful with that magnifying glass you would not want to start any forest fires  Tongue
Posted May 08, 2012, 08:02:51 AM Logged

Offline DaveMorton Topic starter
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Comfort the Disturbed! Disturb the Comfortable!

I got the projector completed, and took some pictures of it:


SideView.jpg
2 weeks till the eclipse!
* SideView.jpg (207.47 KB, 1280x960 - viewed 310 times.)

FrontView.jpg
2 weeks till the eclipse!
* FrontView.jpg (211.45 KB, 960x1024 - viewed 297 times.)

ScreenView.jpg
2 weeks till the eclipse!
* ScreenView.jpg (201.32 KB, 1280x960 - viewed 300 times.)
Posted May 10, 2012, 04:01:09 AM Logged
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Offline Data
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Looks great Dave  Cool, nicely done  thumbsup
Posted May 10, 2012, 11:19:24 AM Logged

Offline Freddy
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Indeed, very impressive and tidy  thumbsup
Posted May 10, 2012, 11:44:33 AM Logged

Offline sybershot
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Came out great, WTG.  thumbsup
Posted May 10, 2012, 13:50:05 PM Logged

Offline DaveMorton Topic starter
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Well, it LOOKS pretty. As to how it's going to work? That remains to be seen. I expect a certain amount of blurring, since the sharpest image is also the one that will ignite the paper, but I'm hoping it will not be so blurry as to be useless. I really can't test that till the eclipse begins, and that's just exactly too late to do anything about it. Smiley
Posted May 10, 2012, 13:53:24 PM Logged
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Offline Data
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Well you can pat yourself on the back for its appearance Smiley

If nothing else its plan B, when we had an eclipse here, few years back now, I had a pair of free very dark glasses from a news paper, or was it a shop  scratch-head hmm! can’t remember but they worked ok.

For me the strangest part was the almost complete darkness in the daytime, something you could miss if you just look at the eclipse its self, don’t know if it gets that dark with an annular eclipse?   
Posted May 10, 2012, 18:56:54 PM Logged

Offline Freddy
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Yeah I used dark glasses and a piece of cardboard with a hole in it plus piece of paper.

Did you notice it all went quiet ?  All the birds stopped chirping.
Posted May 10, 2012, 19:26:23 PM Logged

Offline Data
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Did you notice it all went quiet ?  All the birds stopped chirping.

Yes indeed I did, its was a very strange event, dark and quiet in the middle of the day. 
Posted May 10, 2012, 19:33:57 PM Logged
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