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


Moon and Star Conjunction

Moon and Aldebaran (July 29, 2016)

The waning Moon shone near the bright star Aldebaran in the dawn sky.

This was a beautiful sight this morning, before dawn on July 29. The crescent Moon, its night side illuminated by Earthshine, shone just below the brightest star in Taurus.

We are currently in 3-year period when the Moon’s path is taking it near or in front of Aldebaran every month. However, most of these occultations or conjunctions are not well-timed for any particular location. And many involve the too-brilliant gibbous or full Moon.

But this morning the timing and Moon phase were perfect. From my longitude on Earth in Alberta, the Moon passed closest to the star just before the sky was getting too bright with dawn. Having them set against the deep blue twilight was perfect.

From farther east the Moon would not have appeared as close to Aldebaran as this before sunrise. From farther west the Moon and star would have appeared much lower in the sky at closest approach.

Moon & Aldebaran Screen


For this image I shot 6 exposures, from 2 seconds for the Earthshine, twilight sky colour and stars, to 1/125th second for the bright crescent. I then stacked, aligned, and blended them together using luminosity masks – masks that hide or reveal parts of the image based on the brightness of the scene. You can see them in the Photoshop screen shot – Click on the image to enlarge it.

How do you create these masks?

• Turn off all the layers except the one you want to create a mask for.

• Go to Channels and Command/Control Click on the RGB Channel.

• That automatically selects all the highlights.

• Go back to the image layer and then hit the Add Mask button down at the bottom of the Layers panel (the rectangle with the black dot in it).

• Done. Repeat that for each image layer.

More traditional high dynamic range or “HDR” stacking left odd colour fringing artifacts and double images on the slowly moving Moon, despite applying what is called “de-ghosting” and despite using a mount tracking at the lunar rate. I tried merging the images with HDR, but it didn’t work.

A nifty Photoshop action from the Astronomy Tools set by Noel Carboni added the diffraction spikes.

I shot all images with the 130mm Astro-Physics refractor at f/6 and the Canon 60Da camera at ISO 400.

— Alan, July 29, 2016 / © 2016 Alan Dyer / www.amazingsky.com

Heads Up! – Moon Meet-ups in March

March 21-24, 2015 Evening Sky

This weekend and early next week look for the Moon passing planets and star clusters in the evening sky.

The waxing Moon returns to the evening sky on Saturday night, March 21, a day and half after it eclipsed the Sun over the North Atlantic and Europe.

On Saturday, March 21 look for the thin crescent Moon very low in the west sitting just a degree (two Moon diameters) left of reddish and dim Mars.

The next night, Sunday, March 22, the Moon, now a wider crescent, shines three degrees (half a binocular field) left of brilliant Venus, for a beautiful close conjunction of the night sky’s two brightest objects. The photo ops abound!

This is one of the best Moon-Venus meet-ups of the current “evening star” apparition of Venus this winter and spring. Next month, for example, the Moon will sit six degrees away from Venus on April 21.

On Monday, March 23, the crescent Moon sits between Venus and its next destination, the bright star Aldebaran.

On Tuesday, March 24, the Moon, still a crescent, shines amid the stars of the Hyades star cluster near Aldebaran in Taurus, for a wonderful binocular scene. The more famous Pleiades star cluster is near by.

On all nights, you’ll see the night side of the Moon dimly illuminated by Earthshine, sunlight reflecting off the Earth and lighting up the dark side of the Moon.

March 24, 2015 CU

Here’s a close-up of the March 24 scene, with the Moon in the V-shaped face of Taurus the bull that is marked by the widely scattered Hyades star cluster.

Please note: This diagram and the main chart above, are for western North America. From eastern North America, the Moon will be 2 to 4 Moon diameters lower in the sky for each of the dates indicated.

Clear skies and enjoy the Moon meet-ups in March!

– Alan, March 19, 2015 / © 2015 Alan Dyer / www.amazingsky.net

Dawn Conjunction of Venus and Jupiter

Venus & Jupiter Conjunction, with Moon (August 18, 2014)

It was a fine celestial sight to begin the week, as Venus met Jupiter in the dawn sky.

This morning, August 18, Venus and Jupiter appeared just 1/2 degree apart, as close as they’ve appeared to each other since 1999.

The top image shows the wide-angle setting, with Venus and Jupiter tightly paired near the horizon, and the waning Moon above, itself in conjunction with Aldebaran in the Hyades star cluster.

Venus & Jupiter Conjunction Closeup

This zooms into the main event, the Venus-Jupiter pairing, as they were emerging from the horizon haze.

I shot this from home, off the back deck, having little ambition at 5 a.m. to venture any further afield. I had planned to shoot this from Dinosaur Park but had second thoughts on the hour drive there and back!

Waning Moon in the Hyades near Aldebaran

This zooms into the secondary show this morning, the meeting of the waning crescent Moon with the brightest star in Taurus, Aldebaran, and its companion stars in the Hyades star cluster. This is a telephoto lens shot with a fixed camera, no tracking.

Thus begins a fine two weeks of stargazing, weather permitting, as the Moon exits the sky to leave us the summer Milky Way at its best, and dual pairs of planets in the dusk and dawn sky – Mars and Saturn converging in the evening and Venus and Jupiter, now parting ways, in the morning.

– Alan, August 18, 2014 / © 2014 Alan Dyer


The Moon Meets Jupiter and the Hyades

Moon near Jupiter & Hyades (March 17, 2013)

On Sunday night, March 17, the waxing Moon came very close to Jupiter and the Hyades star cluster for one of the best conjunctions of the year.

This was certainly a night to remember. Minutes after I took the images for this shot, I took the frames for the Comet over the VLA image in the previous post. Here, I caught the Moon shining just below Jupiter (you can see a couple of its moons as well) and just above the Hyades star cluster and the bright yellow star Aldebaran at the bottom of the frame. All are set in the deep blue of twilight.

This is a high dynamic range (HDR) stack of seven exposures ranging from 6 seconds to 1/13 second, to capture the huge range in brightness from the sunlit Moon to the faint stars. Even so, the daylit side of the Moon remains overexposed. But the “dark side of the Moon” lit by Earthshine shows up well. A 135mm telephoto frames the field much as binoculars would show it.

This night recalled a similar evening on April 10, 1997, when Comet Hale-Bopp appeared low in the northwest, much as PANSTARRS is now, and the Moon actually passed in front of Aldebaran. An aurora display also broke loose that night, but not so last night – they are unlikely from New Mexico, though some northern lights were seen the night before from as far south as Colorado.

– Alan, March 18, 2013 / © 2013 Alan Dyer



Winter Sky in Moonlight

Orion & Winter Stars over Old House

Earlier this week I shot a similar scene with the Moon in the photo, when it was near Jupiter. This is the same sky but 5 days later, on January 26, with the Moon now out of the picture, but serving to light up the landscape.

This is the old house on my property that serves as an occasional foreground for test nightscapes. In this case, I was testing my veteran Canon 5D MkII camera against a new Canon 6D. This shot with the 5D MkII had the best arrangement of clouds and stars and works as a decent enough shot on its own.

You can see Orion dodging the clouds, with Sirius at left, and Aldebaran, Jupiter and the Pleiades at upper right.

So what of the tests? Initial impressions are that as far as noise is concerned (always the bane of astrophotographers) the new full-frame Canon 6D improves upon the 5-year old Canon 5D MkII by a factor of two. Noise looks to be about one f-stop better in the 6D, no doubt due to its new Digic V on-board processor.

What this means is:

• Images taken with the 6D at ISO 6400 have a similar level of noise as do images taken at ISO 3200 with the 5D MkII. ISO 3200 images with the 6D look like ISO 1600 images with the 5D MkII, and so on.

• So, if you were happy with shooting at ISO 1600 with the 5D MkII before, you could now shoot at ISO 3200 with the new 6D and get similar results, but with the added benefit of being able to cut your exposure times in half, always a nice thing to do.

• Or conversely, you could continue to shoot with the Canon 6D at ISO 1600 for the same exposure times as before but get shots with much less noise in them. Always a good thing, too!

It’s great to see camera state-of-the-art advancing.

– Alan, January 27, 2013 / © 2013 Alan Dyer

Jupiter Amid the Clusters of Taurus

Jupiter in Taurus (January 4, 2013)

Look up on a clear night this season (winter for us in the northern hemisphere) and you’ll see a bright object shining in Taurus the bull. That’s Jupiter.

This year Jupiter sits in a photogenic region of the sky, directly above the stars of the Hyades star cluster and yellow Aldebaran, the brightest star in Taurus. Above and to the west (right) of Jupiter is the blue Pleiades star cluster.

Over the course of January 2013 you’ll be able to see Jupiter move a little further west each night (to the right in this photo) away from Aldebaran and toward the Pleiades. Jupiter will stop its retrograde motion on January 30. After that it treks eastward to again pass above the Hyades and Aldebaran (returning to where it is now) in early March.

Jupiter’s proximity to Aldebaran and the Hyades makes it easy to follow its retrograde loop over the next few weeks. It’s an easy phenomenon to watch, but explaining it took society hundreds of years and the ultimate in paradigm shifts in thinking, from the self-important arrogance that Earth – and we – were the centre of the universe, to the Sun-centered view of space, with Earth demoted to being just one planet orbiting our star.

I took this image Friday night, January 4, from home as my first astrophoto upon returning to Canada from Australia. It’s a combination of two sets of images: one taken “straight & unfiltered” and one taken through a soft-focus filter to add the glows around the stars and central, brilliant Jupiter. I then blended the filtered images onto the normal images in Photoshop with the Lighten blend mode.

– Alan, January 5, 2013 / © 2013 Alan Dyer