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UltravioletPhotography

Solar Eclipse Oregon: H-Alpha + 3.8OD AstroSolar Film


Cadmium

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The roosters crowed, Venus was straight overhead, and I removed the stack of filters for 57seconds of totality, but the picture doesn't do it justice...sigh.

Total Solar Eclipse, William L. Finley National Wildlife Reserve, Oregon, 10:17am 8-21-2017.

post-87-0-26120100-1503353622.jpg

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More sunning in real life. The blue stretches out further, just not represented the same way in photos.

Here are a few before/after totality shots, using H-Alpha (35nm wide) + 3.8OD AstroSolar stack.

 

Eclipse start:

post-87-0-69616500-1503365952.jpg

 

Eclipse sequence:

post-87-0-25680100-1503365995.jpg

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EXCELLENT !!!!!

 

Really beautiful. That blue is stunning.

 

Andrea, I am calling it 'refreshing full spectrum blue', the "Look Ma, no filters!" look. :-)

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What is the blue there? Is that totality photo UV or "H-alpha" or what? And what exactly IS H-alpha? (I gather it must be one of the sun's absorption lines, but why is it special from a photography viewpoint?)

 

Anyway, amazing photos, Cadmium. I wish mine were as sharp and detailed. My cheap solar foil did its job, but I don't think it's H-alpha or anything.

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Thank you Andy. Well, here is my opinion on all of that.

First off, it is really important when photographing the sun and especially LOOKING at the sun with your eyes, to use a very good 'solar foil'.

 

There are two reasons for the Solar Foil:

1) to protect YOUR EYES!

2) to protect your camera gear.

 

Now, I have only ever tried the Baader foil, and they make two types, 3.8 OD (which is actually a little hard to come by), and the 5.0 OD which is their standard OD, probably because it will protect your eyes, whereas the 3.8 OD will not!

 

The ONLY reason I have the 3.8 OD is because when stacking with the H-Alpha the 5.0 OD is too dark and requires too much exposure time, etc..

In some cases they package the 3.8 OD with the H-Alpha.

 

H-Alpha is 656.28nm, to be exact, and in another topic, someone said that they make it in very narrow bandwidth..

The narrower the more detail. Mine is the cheap one, and is not narrow, mine is 35nm wide.

You get what you pay for...

https://en.wikipedia.org/wiki/H-alpha

 

The reason I was using the H-Alpha is because it seems to sharpen detail.

I have found that detail can be sharpened also by using the Baader U stacked with the AstroSolar film, but the reason I have been trying the H-Alpha is because it is in the visual range, and so my full frame cameras are still stock visual range cameras.

But in fact, i was using it on a UVIR camera here, which works also.

 

What is the blue? I don't know exactly.

The pic was auto WB, and I didn't do anything to it, I didn't white balance it or anything.

 

The AstroSolar is not H-Alpha. Baader doesn't publish the transmission for the AstroSolar film, and I don't know if anyone does.

I wish I knew that, but the H-Alpha is a sperate filter stacked with it.

The AstroSolar 3.8 is simply a neutral density filter of sorts. It is suited for protecting you lens and camera gear, but not strong enough to protect you eyes,

but stacked with the H-Alpha filter the two are quite strong for the camera gear. I would still not view anything optically with anything less than AstroSolar 5.0 OD.

But stacking the H-Alpha with the AstroSolar 5.0 OD will cause you to need way too long of exposures.

So sometimes you will find the H-Alpha sold with the 3.8 OD film.

 

Anyway, thank you. I have been testing these things for 3 weeks in preparation, and even 2 days ago I was getting very poor results, and thus was not expecting the results I got today(!), but it was working good.

I was ready to switch from a UVIR body to a stock visual only body, at the moment of totality, but I only had 57 seconds of totality, and everything was working so well, so all I did was very quickly removed the AstroSolar + H-Alpha stack from the front of the lens and kept shooting in naked-full-tilt-boogy mode. It worked! I didn't want to mess up a good thing when I only had 57 seconds! :-)

 

Sometimes these things work, and sometimes they don't.

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Thanks for all that! Yeah, my solar foil was cheap in price but I got the link off NASA's site, and it passes the appropriate ISO test for human viewing of the sun. I did not use any other filter except some QB21 to cut the IR. Exposure time was F/16 1/20" ISO100 when there weren't clouds.
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Cadmium, those are simply spectacular eclipse fotos. Thank you so much for posting them.

 

I was happy just to get the "shape" of the eclipse with my impromptu U-340 (4mm) shots. :lol: I notice that I did manage to capture one sunspot. So that is an added thrill.

 

But with the solar foil you got some texture of the sun and so many of the sunspots. Just amazing!

 

Before we had the Nikongear meet-up in Scotland, the guys had me order some solar foil to bring for their photographs of the transit of the planet against the sun. I should have kept some of it. But not to late to order for the next time.

 

 

P.S. I would like to give Steve's eclipse photos their own thread. They deserve it!!! [Done.]

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Here is how it looked with the QB21 and TSE17 Solar Filter Foil. Like you, Andrea, I got the general shape and a few sunspots but not tremendous detail. Also my 200mm lens was not really long enough, and on top of that was fairly blurry. (These are crops, of course, and they have been denoised and deblurred with SmartDeblur. And reduced in size...)

 

post-94-0-74706300-1503421051.jpg

 

post-94-0-78127000-1503421063.jpg

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Thank you! :-) I was having poor results the few times I practiced ahead of time, I wasn't expecting good results, but it went well.

The blue is the corona, and it stretched out into the sky almost infinity it seems, and this photo doesn't show how far it reached.

The one thing I was most fascinated with is the magnetic lines in the corona, you see them mostly on both north and south poles of the sun (about positions 10 and 4 o'clock in the photo).

I wasn't expecting to see that.

 

Here is what the shoot scene looked like.

post-87-0-38187200-1503546602.jpg

 

post-87-0-06806200-1503546614.jpg

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Very cool!!

 

May I please have a link to purchasing Solar Film. I once ordered some for the NikonGear Scotland meet-up but have lost that reference. I'm sure there are several places one can go for this. But a link will help me (or others) get started. Thank you!!!!!!

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I purchased some Thousand Oaks Optical Silver-Black Polymer Sheet in 4"x4" from an Amazon reseller who are now sold out.

(Thousand Oaks Optical does not sell directly on Amazon).

 

I also bought an 8.5"x11" directly from Thousand Oaks Optical but ended up not using any of it. The silvered film is the type commonly seen in the eclipse viewers.

http://thousandoaksoptical.com/shop/solar-filters/silver-black-polymer-sheets/

 

I cut down the 4x4" to fit inside a Nikon AF-1 3"x3" gel filter holder and taped it to the front half, silver side facing the sun, so it would not fall out when opened during totality.

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Alpine Astronomical is the central distributor for Baader products in the USA.

If you buy a Baader filter anywhere else in the US it comes from Alpine (B&H, eBay-new, other Astronomy sites...), so I just get mine from Alpine these days, they have the stock.

and the guy who owns it, Bob Luffel, is a really nice guy and very responsive and helpful in email.

http://www.alpineast...Observation.htm

 

Here are their prices:

http://www.alpineast...ing.htm#filters

 

Alpine was the only USA distributor that carried the AstorSolar 3.8 OD film, a seldom used item, compared to the AstroSolar 5.0 OD film (which is what you normally use, and ALWAYS use for viewing with your eyes).

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