Nacreous Clouds Over the Scottish Highlands

February 14, 2012


Photographer: David W. McAllister
Summary Author: Colin McChristie; David W. McAllister; Monika Landy-Gyebnar; Jim Foster

The photo above showing glowing nacreous clouds was snapped in the Scottish Highlands near Tain, Ross-shire, Scotland on the morning of January 12, 2012. This display persisted for almost two hours starting about a half hour before sunrise. During this time, the two prominent rose-colored clouds seemed to move only very slightly even though the winds were blowing steady at near 40 mph (64 km/h). This is characteristic of clouds that form in standing waves, such as lenticular clouds but in this case they formed in the stratosphere.

The similar sized and peculiarly shaped clouds remained just the right distance from the Sun (generally between 5-40 degrees) to glow in bright pink as seen from the photographer's perspective. The Sun is blocked here by the rooftops. Note the blue-tinted iridescent patches or veils beneath each cloud as well as the very small nacreous cloud in between the two larger ones. Always use extreme caution when looking near the Sun.

Photo details: Camera Maker: Canon; Camera Model: Canon PowerShot SX30 IS; Lens: 4.3-150.5 mm; Focal Length: 12.428mm; Aperture: f/4.0; Exposure Time: 0.0025 s (1/400); ISO equiv: 80; Exposure Bias: none; Metering Mode: Matrix; White Balance: Auto; Flash Fired: No (enforced); Orientation: Normal; Color Space: sRGB.