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[-=CROMAN=-]

I had a chance to test out the sun funnel this morning near my office. The clouds were beginning to roll in so I had to move fast. You'll notice a lot of would be sunspots in these photos but only one sunspot is real. Sunspot 1471 .The rest are from the orange rust-like particles that have been embedded into the fabric from years of outdoor usage. My order from Cousins has been shipped so Build #2 will be coming this weekend.

I think the test using the First build sun funnel was a success!







Longhorn hat is perfect for safety


















I do have a concern though. Does the combination of lenses and diffuser material block all vision threatening UV radiation? I can not find a solid answer online. I think this is something we should look into before we proceed with public viewing.

[Chicago Astronomer - Astro Joe]

Rich,

This is a good test run.

I think a shield, on the upper lip of the funnel would help in shading the screen from the ambient/direct angle light - and increase contrast.


How is the sharpness definition?

[-=CROMAN=-]

Joe.. I was able to focus in on the sun spot fairly well. It's not as sharp as one would hope but it definitely works. I agree with the shield. I'm thinking some flexible black foam board would darken things up nicely. The sun funnels are perfect for the transit as you can plop down a small refractor and have it in view and focused in minutes. Although the sun was still low on the horizon this morning the funnel stayed much cooler than I expected. I had the sun in view for well over 10 minutes.

[patrickm]

How will it do for 2 hours?

An answer on UV would be cool before public viewing.

Hook 'em.
p

[Chicago Astronomer - Astro Joe]

I want to see Rich fry an egg on it.

[-=CROMAN=-]

I tried it once again after work when the sun was high overhead and cloud free. I cleaned up the optics a bit and the results were much better than the morning run!

I could actually see the granular variations in the sunspots! My focus was very sharp and the contrast was much better. I tried taking some pics but they would not do the actual image justice.

I give this system a big thumbs up and eagerly await the new Da-lite material to arrive. I can tell you for a fact that the Da-Lite material I'm currently utilizing is not Da-Tex high contrast. The color is a light gray but it works like a charm.

If you put this on a motorized eq mount you'll have yourself a winner for the transit. To be honest I actually prefer this simple system as opposed to the glass filter on my C8.

Beauty in simplicity

[Chicago Astronomer - Astro Joe]

You have sparked my interest Rich...and I think I shall experiment with this as well.

Very cool.

( I have just ordered mine - four really - 'cause 1 ain't enough for the Chicago Astronomer. A comparison of the Quad-screenings in action in a week or so.)

[Paulie pchris00]

May 3, 2012 11:49:54 GMT -6 patrickm said:

An answer on UV would be cool before public viewing.

I don't have an answer, but have thought about this for awhile.

Even if there is some UV light coming through the screen, it isn't a direct blast to the eyeball. Most viewers will be a few feet from the screen, and I think there would be enough scatter that it wouldn't be any more harmful than being outside on a sunny day without sunglasses. I think this is safe enough, and a much better option than having the public using smoked glass or some other concoction to view the transit on their own.

We should still try to find out what the UV exposure would be, but unless we find out something definitive, this looks like one of the best options for mass solar observing.

[-=CROMAN=-]

we're good. the refractors glass takes care of the uv radiation

[Chicago Astronomer - Astro Joe]

I keep a UV filter on the 2" diagonal, screwed into the the Light Pollution filter - both permanently attached at all times.

Perhaps an inexpensive UV filter would be recommended as cheap insurance and peace of mind. If anything, it'll help keep the dust out and won't affect visuals.

Now, raw Chinese Powered Green lasers are another story....

[-=CROMAN=-]

Good idea. Just received a baader uv filter yesterday.

[-=CROMAN=-]

Update... I received the order from cousins. The material was a tad bit darker than what I had. I mounted it with an 18mm today. The details in the sun spots are outstanding! We have a winner. Check out facebook.com/iskywatch for the latest images. I'll try to post them here later