Here are some nice ice halos at the passage of a particular layer of clouds, during a clear sky day (2023-04-04, from near Dole, Jura, France).
This clouds layers gave an extraodinary sharp looking display of ice halos, as I rarely saw in 15 years of watching.
I was then in the good spot at the right time, for this one.
While I was taking care of my lawn, during a clear sky day, I saw some high altitude clouds coming from the north, and decided to take the bet I will have some ice halos, but I did not epected that kind of sharp halos.
In all the below images, clouds are coming from the left (North-East).
On this first stack image, you can see the Wegener arc, with almost the part crossing the parhelic circle. There is also the 120° parhelion with reddish edge as well as on the circle.
Process is (as an example of how I do usually, for the image shown above,
named 2023-04-04
-[14h57to15h37]-
bw-
[4-2]-
UsM(11)-
5s5-
notrack-
UsM.bmp):
→ B-R ( -
bw ) rendering of all the images of the sequence (
-[14h57to15h37] ),
→ 11th stack (
(11) ) of the sequence with 4 images (
-[4 ),
→ then Unsharp mask on this stack ( -
UsM ),
→ then a new stack (with Registax, without the track on the sun ( -
notrack ))
→ of 5 ( -
5s5 ) of last stacks (those ones taken every 2 images (
-2] ))
→ then one more Unsharp filter ( -
UsM ) to end it.
Later, like 5-6 minutes later, the layer of clouds enter the 46° FoV from the sun, which gave the most impressive part of the display to me.
Here is one single image, with just B-R rendering (no UsM or what so ever).
Then 2 stack versions witht this image along with some before and after, to see more clearly the Lowitz & Parry display, (on the above one, we can see parts of 46° halo, but not in whiole, because of the hole in the clouds crossing the view... I guess)
and with the images when the clouds are on the side of the sun from my point of view. I even manage to watch clearly the circumscribed halo while i was cutting my lawn.
You can also see the left part of lower Parry arc tangent with the circumscribed halo.
A last part of the display, with clouds on the bottom left of the sun, to see the extension of the lower Lowitz and the extension of the left part of the Lower Parry, tangent to the circumscribed halo.
For this stack, a "min" function is applied during the stacking process, in order to keep the minimum value of each pixel while stacking, and try to make the black forms therefore the colored halos more visible.
A crop on the left sundog, to see the Lowitz crossing and the 2 Parry arcs.
I have not presented any colored versions, because of the heterogeneous form of the clouds mask the halos for this display.
Finally, a time-lapse of the display is available here, which a compilation of differents time-lapses (one for each processing type).
From those images are extracted the previous posted here :
www.flickr.com/photos/gaukouphoto/52808574767/in/dateposted/
All images are taken with Canon EoS 6D + 8mm Samyang lens from my roof windows, South-South-East side.
Settings: 1/1000s, ISO100, f/9,4, 1 image every 12s.
Sun mean height is 47° at the time of the sequence.
Google Drive
folder shared, with all the images presented here, and the time-lapse.
I still have all the raws of the sequence if needed too.
