Strange 22° Solar Halo

[Emil Ivanov]

Hello everybody,

I’m not sure where to post this topic. If the moderators find that this is not the appropriate place, please, move it.
About one hour ago I took this picture of (strange?) 22° Solar halo:

Click to view full size image

Does somebody have an idea what this colored radial stripes are? And also the partially seen second (slightly larger, about 30°) halo, at the left side, near the bird?
I’m quite sure this is from the optics, but couldn’t find any explanation .
The image was taken with Canon 40D digital camera and 10mm f/4 lenses at 100 ISO. Exp. time was 1/4000s.
The altitude of the Sun was about 50° above horizon

Thanks in advance, Emil

[owlice]

Emil, you might want to send that image to both Les at Atmospheric Optics and to the Cloud Appreciation Society. I think the halo is a normal one; it's the clouds that allow it to appear that are unusual. The halo near the bird looks like iridescence; if there were a larger bank of cirrus clouds there, I think it would be more apparent. Did you see the radial stripes with the naked eye? And was this within the flight path of air traffic? I'm wondering if the radial stripes are from a fallstreak event and the sun is simply in the right position to illuminate them.

(I have no expertise in ... well, anything, so grain of salt and all that. )

ETA: Ah, yes, there is probably air traffic in that part of the sky, because the area that is showing what I think is some iridescence looks like (part of) a contrail.

Such an interesting photo!

[Emil Ivanov]

Thank you owlice,

You’re right about the air traffic: there is a lot of it, as you can see from this photo (another halo ), taken on May 4th:

Click to view full size image

The Sun was approximately at the same point of the Sky. But on this photo there aren't these strange radial stripes. It’s true that the cloud cover was denser than today.
About your question: no, I didn't see the radial stripes with naked eye. (probably I didn't because the Sun was too bright )
I think also that your reasoning about the second (partial) halo are absolutely correct.

Thanks again and kind regards, Emil

[owlice]

In looking at this more, I... just don't know. Some of the stripes on the left of the image look as though they may be optical effects from the camera, but others, such as the ones on the bottom of the image, look as though they may not be. 'Tis a puzzlement to me!

[RJN]

Hi Emil,
Did you see those rays with your own eyes, or were you surprised to see them (only) on the camera's image?
- RJN

[geckzilla]

Uh oh, RJN's looking for a replay of the Triple Sunrise thread.

[neufer]

http://asterisk.apod.com/viewtopic.php? ... 72#p173639

[owlice]

geckzilla, I'm very curious about this; I think Emil's questions very good ones. I have never seen an image like this!

[RJN]

Oops so you already said that you didn't see them with your eyes. I am trying to tell if the radial streaks are foreground to the clouds and bird, or background. For a while I thought they were clearly foreground, but now I am again unsure. Zooming in on the bird shows no obvious signs of the streaks, which might have been present were the radial streaks foreground. Thoughts? - RJN

[RJN]

Since there are obvious lens flares in the image, like the one going toward the top of the image, and since lens flares can mimic this effect (e.g. http://www.adorama.com/catalog.tpl?op=article_012703 ), my best bet currently is that this is just a pretty set of lens flares. - RJN

[Chris Peterson]

I’m quite sure this is from the optics, but couldn’t find any explanation.

I agree. Did you have any filters in front of the lens? With or without a filter, I'd suspect some kind of streaking on the lens/filter surface, or sleeks, which are microscopic scratches (usually on coated surfaces) created when you clean them with too much pressure or not using a fluid. I've seen flare like this around stars in telescopes with sleeked mirrors.

Try taking a test image with the same equipment using a bright, near point source- the Sun again, or something like a halogen light if you're indoors. Try some different exposures to see if this shows up (typically overexposing the source).

[Emil Ivanov]

Apologies for the late response.
I wanted to do the experiment Chris suggested

Try taking a test image with the same equipment using a bright, near point source- the Sun again, or something like a halogen light if you're indoors.

and did today the same image (same position of the Sun, same camera, lenses, F-ratio and exposure time and almost same weather conditions). Here the result:

Click to view full size image

Radial rays can be seen but not this colored stripes.

Nonetheless I have to agree with RJN:

Since there are obvious lens flares in the image, like the one going toward the top of the image, and since lens flares can mimic this effect (e.g. http://www.adorama.com/catalog.tpl?op=article_012703 ), my best bet currently is that this is just a pretty set of lens flares. - RJN

I think this was a combination between the current weather conditions yesterday and some kind of funny reflections somewhere inside my 12 elements lenses .

As proof two more pictures from yesteday:

Click to view full size image

Click to view full size image

They are taken about 15 sec. apart from each other and about 40 seconds after the first one. Unfortunately I didn’t make more exposures. The halo was barely seen with naked eye therefore I didn’t pay a lot of attention . As mentioned, I saw the stripes later, on the computer monitor.

Best regards, Emil

[Emil Ivanov]

Did you have any filters in front of the lens? With or without a filter, I'd suspect some kind of streaking on the lens/filter surface, or sleeks, which are microscopic scratches (usually on coated surfaces) created when you clean them with too much pressure or not using a fluid. I've seen flare like this around stars in telescopes with sleeked mirrors.

Sorry Chris, forgot to say that I didn’t use any filters in front of the lenses.
Btw, I also think the most likely reason for the stripes are these microscopic scratches you mentioned.