Dawn Sky Delights


Aldebaran About to be Occulted by the Moon

It was one of those mornings when the sky was full of wonder.

After days and nights of smoke from unfortunate fires burning not far away, including in my favourite national park of Waterton Lakes, the sky cleared enough this morning, September 12, to reveal some fine sights.

At 6 a.m. the waning gibbous Moon passed in front of the star Aldebaran in Taurus. It is performing many such occultations of Aldebaran this year, but most aren’t well seen from any one location. This one was ideal, right from my backyard.

The lead image is a “high dynamic range” stack of several exposures showing the waning Moon and star set in some high haze adding the sky colours.

The star winked out behind the Moon’s bright limb as the Moon advanced from right to left (west to east) against the background sky.

Occultation of Aldebaran
Aldebaran nearing the limb of the Moon.
This shows a composite sequence, with images of the star taken every four minutes blended with a single image of the Moon. While it looks like the star is moving, it is really the Moon that is edging closer to Aldebaran.

The star reappeared from behind the dark limb of the Moon, but five minutes after sunrise, with the Moon in a bright blue sky. Still, the star stood out nicely in binoculars and in the telescope for this view.

Aldebaran Near the Moon in Day Sky
Aldebaran off the dark limb of the Moon.
Aldebaran is the point of light at right, just off the invisible edge of the Moon.

I shot stills and video, and compiled them into this short video.

Enlarge it to full screen to view it properly.

Meanwhile, over to the east the twilight sky was awash in planets.

Rocky Planets at Dawn with Labels (Sept. 12, 2017)
The line of dawn planets, with labels.
All the three inner terrestrial worlds were there: Venus, at top, Mercury below Regulus, and Mars lowest of the trio. Of course, a fourth terrestrial world is in the photo, too – Earth!

Mercury was at its greatest western elongation this morning, placing it as far from the Sun and as high in the sky as it gets, with this autumn appearance the best of 2017 for a morning showing for Mercury. Even so, you can see how Mercury is always low and easy to miss. However, this morning it was obvious to the naked eye.

Mars and Mercury will be in close conjunction at dawn on the morning of September 16.

Rocky Planets at Dawn (Sept. 12, 2017)

It was a fine morning to be up early and enjoy the solar system show.

— Alan, September 12, 2017 / © 2017 Alan Dyer / amazingsky.com

 

Old Moon Waning


It’s been a season of crescents. A crescent Sun in eclipse. A crescent Venus before and after transit. But this is the more familiar Moon.

I caught the waning crescent Moon rising before the dawn on Saturday, June 16, after an all-night shooting session amid the summer twilight. As dawn was breaking, the Moon rose in the east and drifted through clouds near the horizon.

Here, the glow of Earthshine lighting up the dark night side of the Moon  appears just a little brighter than the twilight sky.

This is an “old Moon,” as at this phase the Moon is three days before new, at age 26 days. At new moon, the Moon is “reborn” and appears anew as a crescent in the evening sky.

— Alan, June 16, 2012 / © 2012 Alan Dyer