Heads Up! – Mercury Rising


May 6 Mercury

The next two weeks are the best in 2015 for sighting Mercury in the evening sky.

Mercury is coming into view in our evening sky, climbing as high as it can get for us in the Northern Hemisphere. This is our best chance for us to sight Mercury as an evening star in 2015.

Spring is always the best time to catch elusive Mercury. The angle of the ecliptic – the path of the planets – swings up highest above the horizon in spring, putting Mercury as high into the evening twilight as it can get. This makes it easier to sight Mercury than at other times of the year when, particularly for observers at northern latitudes, Mercury can be lost in the twilight glow and horizon haze.

When it is at its highest Mercury is surprisingly bright, appearing as a bright star easily visible to the naked eye. However, locating it at first in the twilight usually requires a scan with binoculars.

Mercury will be at its highest on May 6 when it reaches “greatest elongation.” However, it will be almost as good for a week on either side of that date.

So set aside a clear evening during the first two weeks of May to search for the inner planet. (The green line is Mercury’s path relative to the horizon with the green dots marking its position at daily intervals.)

Mercury will be shining above fainter Mars, and well below brilliant Venus, now dominating our evening spring sky. Look north of due west during the hour after sunset.

Mercury & Venus Conjunction Closeup (Jan. 10, 2015)
Mercury and Venus on January 10, 2015 from New Mexico.

This view captures Mercury at its last good evening appearance, back in early January when it appeared close to Venus, then emerging into the evening sky. You can compare their relative brightness.

By coincidence, the emergence of Mercury into our evening sky comes just as it loses its lone visitor from Earth. Since 2011, NASA’s Messenger probe has been orbiting and mapping Mercury.

On April 29, with the probe exhausted of its maneuvering fuel, Messenger is scheduled to end its mission by crashing onto the planet, adding a new crater to Mercury’s barren and volcanic surface.

A global false-color map of the mineral composition of Mercury from Messenger data.
A global false-color map of the mineral composition of Mercury from Messenger data.

This is a recent map of Mercury from Messenger. For more details, see the mission’s website.

– Alan, April 30, 2015 / © 2015 Alan Dyer / www.amazingsky.com

Amazing Scenery on the Eight-Day Moon


Along the Terminator of the Eight-Day Moon

Incredible detail stands out along the terminator of the eight-day Moon.

This was the Moon on the evening of April 26, with the waxing Moon eight days past New and one day past First Quarter Moon. It’s a great phase to explore the surface of the Moon.

In the north the arcs of the Alps and Apennine mountain ranges encircle Mare Imbrium.

In the south, craters pepper the Highlands in stark relief. Tonight, the Straight Wall was just beginning to catch the light of the rising Sun, creating a very sharp, straight shadow.

The regions along the terminator – the boundary between light and dark – at left are seeing the first sunlight in two weeks. To the right, on the more brightly lit portion of the near side of the Moon, the dark mare areas stand out in various shades of grey. Systems of rays splash out from bright, geologically fresh crater impacts.

On the technical side, this is a mosaic of two overlapping images, one for the northern and one for the southern hemisphere, taken through a Celestron C9.25 telescope at a focal length of 2300mm. I stitched them with Adobe Camera Raw’s new (as of last week’s update) ability to stitch images into a Raw-format panorama file.

– Alan, April 26, 2015 / © 2015 Alan Dyer / www.amazingsky.com

Conjunction Over the Old Barn


Moon & Venus over Old Barn

The Moon and Venus shine in conjunction over an old pioneer barn.

Tonight, April 21, the waxing crescent Moon passed a wide eight degrees to the left of Venus. That’s a wide conjunction to be sure, if we can even call it a conjunction!

Nevertheless, when the two brightest objects in the night sky come together it’s worth looking at and photographing.

I had planned to drive west, to the Kananaskis area of southern Alberta, to shoot the celestial scene over the Rockies. But clouds to the west thwarted those plans.

As it is, I still fought the oncoming clouds out on the plains. I chose a favourite old barn near home. It made a rustic foreground to the twilight sky.

Venus remains a brilliant “evening star” all spring and into the early summer. We’ll see a similar wide passage of the crescent Moon by Venus a month from now, on the evening of May 21.

– Alan, April 21, 2015 / © 2015 Alan Dyer / www.amazingsky.com

Heads Up! – Dual Conjunctions in the Spring Sky


April 21 Moon & Venus

On the evening of April 21 the waxing Moon shines near Venus, while Mercury appears near Mars.

Say goodbye to the winter sky, as Orion and Taurus sink into the western twilight. Joining them is an array of planets, and the Moon.

Look west on April 21 and you’ll see the waxing crescent Moon near brilliant Venus, with both above the Hyades star cluster and the bright star Aldebaran in Taurus.

The thinner Moon will appear below Venus the night before, on April 21, while on April 22, the waxing Moon, then a wider crescent, will sit well above Venus.

If you have an unobstructed view to the west also look for the pairing of Mercury and Mars low in the twilight. You might need to use binoculars to pick them out.

Mercury is just beginning its best evening appearance of the year for the northern hemisphere. So if you miss it April 21, you have another couple of weeks to find it in the evening sky.

Waxing Moon Amid the Hyades (Telescope)

On the nights around April 21, also look for Earthshine lighting the dark side of the Moon. You can see the night side of the Moon because it is being illuminated by sunlight reflecting off the Earth, shining brightly in the lunar sky.

The above image is a view of Earthshine from a month ago, on March 24, when the Moon appeared in the Hyades star cluster.

Enjoy the spring sky adorned by Venus as a bright “evening star,” and joined by the Moon on April 21.

– Alan, April 17, 2015 / © 2015 Alan Dyer / www.amazingsky.com

 

Back Under the Northern Lights


Aurora & Old Pioneer House

The aurora dances behind a pioneer homestead on the Alberta prairies.

After a stay of five months in New Mexico I arrived back in Alberta earlier this week, and was greeted tonight, April 15, with a display of Northern Lights. They’ve been very active in the last month, but I’ve seen nothing of them from where I was in New Mexico.

But here in southern Alberta, I just walk out onto my back deck and there they are! An email alert prompted me to have a look, after predictions earlier in the day called for little activity tonight. But indicators picked up nicely late in the evening.

I headed to an abandoned pioneer homestead near my acreage. A photogenic foreground always adds to the scene.

Aurora over Prairie Pond

A little further down the road is a prairie pond, ruffled a little by wind tonight, blurring the reflection I was hoping to capture.

It’s nice to be back under the Northern Lights. Bring them on!

– Alan, April 16, 2015 / © 2015 Alan Dyer / www.amazingsky.com

Heads Up! – Planets Pair with Clusters


April 11 Venus & M45

Look west and south this weekend to see the two brightest planets each pairing with a bright cluster of stars.

This weekend, Venus and Jupiter each pair with a prominent open star cluster.

In the west, look for brilliant Venus, an evening “star” this spring, shining near the Pleiades, or Seven Sisters star cluster. Some know it as Messier 45.

Both Venus and the Pleiades are in Taurus the bull, whose main stars lie to the left of the Venus-Pleiades pairing. Farther to the left still, look for the distinctive stars of Orion the hunter, whose trio of Belt stars give him away.

April 11 Venus & M45 CU

As this close up shows, binoculars will nicely frame Venus and the Pleiades at once.

Venus continues to climb higher this spring while the Pleiades and the other stars of the winter sky, including Orion and Taurus, sink lower and lower. The next few nights are the best for catching Venus as it passes the Pleiades.

April 11 Jupter & M44

High in the south as it gets dark shines the other bright planet in our sky – Jupiter.

It, too pairs with a star cluster. Jupiter now shines a binocular field to the east (left) of the Beehive Cluster, also known as Messier 44. Jupiter and M44 lie in Cancer the crab, a faint constellation nestled between Leo to the east and Gemini to the west.

Jupiter has been retrograding closer to the Beehive all winter and early spring. But this weekend Jupiter sits as close to the cluster as it is going to get. For the rest of spring and summer Jupiter will move east away from the Beehive.

Look west and south as it gets dark this weekend, for the pair of planet-cluster pairings!

Clear skies and happy stargazing.

– Alan, April 9, 2015 / © 2015 Alan Dyer / www.amazingsky.com

 

Nightscapes at Double Arch


Star Trails Behind Double Arch

The iconic Double Arch looks great under dark skies, moonlight, or painted with artificial light.

Last night, I returned to the Double Arch at Arches National Park, to capture a star trail series, starting from the onset of darkness at 9:30 p.m., and continuing for 2.5 hours until midnight, an hour after moonrise at 11:00 p.m. The lead image is the result.

I think it turned out rather well.

The Big Dipper is just streaking into frame at top right, as I knew it would from shooting here the night before. The bright streak at upper left is Jupiter turning into frame at the end of the sequence. Note how the shadow of the moonlit foreground arch matches the shape of the background arch.

On the technical end, the star trail composite is a stack of 160 frames, each 45 seconds at f/2.8 and ISO 3200, with the Canon 6D and 14mm lens. The foreground, however, comes from a stack of 8 frames taken toward the end of the shoot, as the moonlight was beginning to light the arches. An additional 45-second exposure taken a couple of minutes after the last star trail frame adds the star-like points at the “head” of the star trail streaks.

I used the excellent Advanced Stacker Actions from StarCircleAcademy to do the stacking in Photoshop.

Dark Sky Behind Double Arch

Before starting the star trail set, I took some initial short-exposure nightscapes while the sky was still dark. The result is the above image, of Double Arch in a dark sky. Passing car headlights provided some rather nice accent illumination.

On such a fine night I thought others might be there as well. Arches is a very popular place for nightscape imaging.

Sure enough, 6 others came and went through the early evening before moonrise. We had a nice time chatting about gear and techniques.

As expected, a few photographers came armed with bright lights for artificially lighting the arches. I kept my camera running, knowing any illumination they shone on the foreground wouldn’t affect my star trails, and that I’d mask in the foreground from frames taken after moonrise.

Photographer Lighting Double Arch

Here’s one frame from my star trail sequence where one photographer headed under the arch to light it for his photos. It did make for a nice scene – a human figure adds scale and dimension.

However, I always find the light from the LED lamps too artificial and harsh, and comes from the wrong direction to look natural. I also question the ethics of blasting a dark sky site with artificial light.

On a night like this I’d rather wait until moonrise and let nature provide the more uniform, warmer illumination with natural shadows.

Big Dipper over Double Arch

As an example, I took this image the night before using short exposures in the moonlight to capture the Big Dipper over Double Arch. When I shot this at 11 p.m. I had the site to myself. Getting nature to provide the right light requires the photographer’s rule of “waiting for the light.”

– Alan, April 7, 2015 / © 2015 Alan Dyer / www.amazingsky.com