Belt of Venus and Volcanoes


This was the scene we were treated to each evening at the Atacama Lodge in Chile. Quite an amazing skyline, with 5,900-metre-high Licancabur Volcano, here at sunset.

The sky colour comes from a phenomenon known as the Belt of Venus, a magenta/pinkish glow from sunlight lighting up the upper atmosphere after the Sun has set for us on the ground. The dark blue rimming the horizon is the rising shadow of the Earth.

I have punched up the colour saturation here to bring out the colours, but not so much as to be faked — the colours are real!

This is a shot with the 50mm lens and Canon 7D camera, taken on one of the nights we had dinner back at the lodge, in this case with a group of Québec amateur astronomers also here this week who were great observing friends on the field.

– Alan, May 7, 2011 / Image © 2011 Alan Dyer

Dawn’s Early Light


This shot took getting up early (rather than staying up all night) to shoot the sky at 5 a.m. The main subject here is a subtle tower of light rising up vertically from the eastern horizon. That’s the Zodiacal Light, best seen from low latitudes.

The glow is from sunlight reflected off dust particles deposited in the inner solar system by passing comets. While it looks like dawn twilight coming on, the light actually comes from out in space and heralds the brightening of the sky by true twilight.

After a week of gazing in the evening sky, a number of us observers took the opportunity this morning to snooze through part of the night and get up prior to dawn to see a new set of objects. At that time of night, and at this time of year, the centre of the Milky Way sits straight overhead, and shows up here in an ultrawide shot from horizon to zenith.

I shot this with the 15mm lens at f/2.8 and the Canon 5D MkII at ISO 800. It’s a stack of two 3-minute exposures.

– Alan, May 6, 2011 / Image © 2011 Alan Dyer

After the Blizzard


We’ve certainly had our share (more than our share!) of snowstorms and blizzards so far this winter, though nothing like people down east have experienced. The one saving grace is that after the storm the sky often clears beautifully. In this case, on January 30, 2011 we had very clear blue skies, but filled with ice crystals of just the right shape (hexagonal) and orientation to produce a classic solar halo, with prominent sundogs on the 22° halo and a hint of an upper tangent arc, or is it an upper Parry arc? A trace of a circumhorizontal arc is also visible parallel to the horizon. Solar haloes are fascinating and often unique — each one can display a slightly different set of halo phenomena.

The website Atmospheric Optics gives great information and reference works.

– Alan, January 2011 / Image © 2011 Alan Dyer