Saturday morning just after 10 the eastern sky seemed to be full of contrails. There was also a faint parhelion, or sundog.

Shooting into the sun is not a great way to get much detail, but this worked fairly well. The sundog is a little to the left of the sun (about 22°, exactly where it should be). The small, bright blue dot further to the left and down a little is apparently an artifact of the lens of my iPhone.

I haven’t seen quite this many contrails at one time around here. We are close to some flight paths to the Atlanta airport, so airliners often fly overhead. Delta flies almost directly over our house on the Huntsville-Atlanta route; I once actually saw our old house from a Huntsville-Atlanta leg on my way out to California. Contrails usually dissipate before many more planes fly over, but not Saturday morning.

This sundog was a little higher in the sky than one usually sees. They are fairly common if you know when and where to look, usually seen in early morning or late afternoon, fairly close to the horizon. They are usually formed by plate-shaped ice crystals, which tend to orient themselves horizontally as they fall through the atmosphere. The sun’s rays have to pass through them edgewise to form the partial 22° halo, of which the sundog is a part. In order to see them at higher sun elevations, the crystals have to be column-shaped so that they have random orientations as they fall. If the ice crystals are randomly oriented at least some fraction will be at the right orientation to let sunlight pass through them so that a sundog will be visible. And so it was last Saturday.

I love looking out our windows.