Arc and sundog!

Hi guys,

It's been a good day of solar activity. I also got this shot of an arc. Can someone please identify which arc it is? A sundog was also visible to the right of the sun and I have a few shots of it which I might add later.

I hope you enjoy!

Details of first pic. Canon 20D with 17-40L f4 @ 23mm, f9 and 1/3200s. ISO400.

Deatils of second. Canon 20D with 70-200L f4 @ 70mm, f7.1 and 1/2500s. ISO400.






Thanks,

Daniel

hi Dan,

beautiful shots . . . many thanks for the call earlier about the display. The phenomenon is definitely an upper tangent arc. Les Crowley's web site at www.sundog.clara.co.uk/atoptics/phenom.htm has a nice example in the "Ice Halos" section. Well worth looking at too are Pekka Paraveninen's photos at www.polarimage.fi


atb,

John

WOW That is an excellent set of images!

It looks like you have captured a 22* solar halo, a solar pillar, sundogs and what looks like a very pronounced upper tanget arc!

Amazing!

Thank you very much for the links, John - they're wonderful. The Finnish photographer's works is superb!

Also many thanks to you, Martin. I always love to see your posts as you tend to get brilliant images of these phenomena. Certainly I did see 2 sundogs, a 22degree halo, a solar pillar and that upper tanger tangent arc - but not all at the same time for one great photo! Still I'm very pleased with what I got

I couldn't believe it when I looked out the window and saw the arc. I clumped my camera gear into my chest and climbed onto the garage roof.

It's been a good day! Now, a nice auroral storm would really top it off. Do I ask too much?

I may have seen something similar on the same day



and a close-up



If anyone can let me know what this is ... is it an arc or a sun-dog ??

Observed around 4:30pm in Naas, on 11th September.

hi Shane,

very nice pictures . . . they bring out the colour well. What you have captured is a sundog or "mock-Sun". The technical name is a parhelion ("beside the Sun") -- you can also get parselenes (beside the Moon) but these are fainter because the light source, the Moon, is obviously fainter.

sundogs always sit on the 22° halo, the most common "ring" around the Sun though you don't necessarily need to see the halo to have a sundog.

look closely at the outside edge of a sundog and you can sometimes see they have a "tail"! This is the parhelic circle which, as the name suggests, is a thin strip of light parallel bisecting both the 22° halo and the Sun itself. It can stretch almost the whole way around the sky parallel to the horizon but at the same altitude as the Sun. I think Les Crowley's site mentioned above has a photo of one.

John