2007. július 30., hétfő

Giving better looks for the stacked images

There is no denying it - stacked and unsharp masked halo image can be rather ugly. Ground objects are blurred and horizon is coated with blue glow.

But the looks can be improved by taking the ground from single untreated frame. That's what is done in the upper right image. It is the same image as the upper left except for the ground.

Near the horizon the clouds from the single frame dominate the sky, but in this case it has no significance as the halos are anyway blurred at the horizon. This technique works best with high sun displays where halos are far from ground objects.

The display was seen in Lahti on June 9. The upper image pair is stacked (using Registax) from 72 frames taken during 15 minutes. The lower is 60 frames /12 minutes stack. It shows lower 24 plate arc on the right and perhaps some 24 halo on the left. Jukka Ruoskanen also photographed the display some 40 kilometres from Lahti. Another example of the ground adding is here.

2007. július 1., vasárnap

Odd radius halo 6-19-07

While at work on break time I noticed there were cirrus clouds in the sky and I decided to check for halos and I got three odd radius halos which were 9, 18 and 22 or 23? degree rings. I took a few photos. I unsharp masked one of them the show the halos more clearly. This was probably the only halo highlight of June but nothing super special but it beats nothing.