ecliptic – The Amazing Sky

April 9, 2019

The Waxing Moon of Spring

Spring is the season for Earthshine on the waxing Moon.

April 8 was the perfect night for capturing the waxing crescent Moon illuminated both by the Sun and by the Earth.

The phase was a 4-day-old Moon, old enough to be high in the sky, but young enough – i.e. a thin enough crescent – that its bright side didn’t wash out the dark side!

In the lead photo at top, and even in the single-exposure image below taken earlier in a brighter sky, you can see the night side of the Moon faintly glowing a deep blue, and brighter than the background twilight sky.

Four-Day-Old Moon in Blue Twilight — The 4-day-old waxing crescent Moon on April 8, 2019 in a single exposure when the Moon was still in the bright blue twilight. Even so, the faint Earthshine is just becoming visible. This is with the 105mm Traveler refractor and 2X AP Barlow lens for an effective focal length of 1200mm at f/12, and with the cropped-frame Canon 60Da at ISO 400, in a single 1/8-second exposure.

This, too, is from sunlight, but light that has bounced off the Earth first to then light up the night side of the Moon.

If you were standing on the lunar surface on the night side, the Sun would be below the horizon but your sky would contain a brilliant blue and almost Full Earth lighting your night, much as the Moon lights our Earthly nights. However, Earth is some 80 times brighter in the Moon’s sky than even the Full Moon is in our sky.

Four-Day-Old Moon with Earthshine — The 4-day-old waxing crescent Moon on April 8, 2019 in a blend of short and long exposures to bring out the faint Earthshine on the dark side of the Moon and deep blue twilight sky while retaining details in the bright sunlit crescent. This is with the 105mm Traveler refractor and 2X AP Barlow lens for an effective focal length of 1200mm at f/12, and with the cropped-frame Canon 60Da at ISO 400, in a blend of 7 exposures from 1/30 second to 2 seconds, blended with luminosity masks from ADP Pro3 extension panel in Photoshop.

Unlike the single image, the lead image, repeated just above, is a multi-exposure blend (using luminosity masks), to bring out the faint Earthshine and deep blue sky, while retaining details in the bright crescent.

Once the sky gets dark enough to see Earthshine well, no single exposure can record the full range in brightness on both the day and night sides of the Moon.

Waxing Moon, Mars and the Taurus Clusters — The 4-day-old waxing crescent Moon on April 8, 2019 with it below Mars (at top) and the star clusters, the Hyades (at left, with reddish Aldebaran) and Pleiades (at right) in Taurus, and set into the deep blue evening twilight. This is with the 135mm Canon telephoto at f/2.8 with the Canon 6D at ISO 400, in a blend of 7 exposures from 1/4 second to 8 seconds, blended with luminosity masks from ADP Pro3 extension panel in Photoshop, to prevent the Moon from being too overexposed while retaining the stars and blue sky. The camera was tracking the sky.

April 8 was a great night for lunar fans as the crescent Moon also appeared between the two bright star clusters in Taurus, the Hyades and Pleiades, and below reddish Mars.

It was a fine gathering of celestial sights, captured above with a telephoto lens.

April 8 Sky

This show the chart I used to plan the framing, created with StarryNight™ software and showing the field of the 135mm lens I used.

The chart also shows why spring is best for the waxing Moon. It is at this time of year that the ecliptic – the green line – swings highest into the evening sky, taking the Moon with it, placing it high in the west above obscuring haze.

That makes it easier to see and shoot the subtle Earthshine. And to see sharp details on the Moon.

$The 4-day-old waxing crescent Moon on April 8, 2019 exposed for just the bright sunlit crescent, revealing details along the terminator. This is with the 105mm Traveler refractor and 2X AP Barlow lens for an effective focal length of 1200mm at f/12, and with the cropped-frame Canon 60Da at ISO 400, for a single exposure of 1/60 second. This is not a stack or mosaic.$

The 4-day-old waxing crescent Moon on April 8, 2019 exposed for just the bright sunlit crescent, revealing details along the terminator. This is with the 105mm Traveler refractor and 2X AP Barlow lens for an effective focal length of 1200mm at f/12, and with the cropped-frame Canon 60Da at ISO 400, for a single exposure of 1/60 second. This is not a stack or mosaic.

After the sky got darker I shot the crescent Moon in a short exposure to capture just the bright crescent, included above in two versions – plain and with labels attached marking the major features visible on a 4-day Moon.

If you missed “Earthshine night” this month, mark May 7 and 8 on your calendar for next month’s opportunities.

Clear skies!

December 5, 2015

Circles and Lines in the Dawn Sky

Cloud hid Comet Catalina but added a halo around the waning Moon, intersected by the line of the ecliptic.

I’m in Arizona, just inside the state line with New Mexico, on a quest to shoot Comet Catalina at dawn. Clouds prevented any view of the faint comet this morning but provided a fine consolation prize.

The waning crescent Moon was surrounded by an ice crystal halo, a rare sight around a thin Moon. The Moon was between Mars and Jupiter, heading toward a conjunction with Venus, below, on December 7.

The line of Venus, Mars, the Moon, and Jupiter, plus the stars Spica and Regulus defined the line of the ecliptic beautifully in the pre-dawn sky.

A classic 22° ice crystal halo around the waning crescent Moon, here overexposed, with the Moon between Jupiter and Mars in the morning sky on December 5, 2015. Seeing a halo around a crescent Moon is somewhat rare as they usually require the brighter light of the Full Moon. Venus is the brightest object at bottom closest to the horizon. The three planets, along with the stars Spica (above Venus) and Regulus (at top of frame) define the line of the ecliptic here in the dawn late autumn / early winter sky. I captured this scene from southeast Arizona near the Arizona Sky Village at Portal. This is a stack of 4 exposures from long to short (8s to 1/2s) to encompass the great range in brightness and not overexpose the crescent Moon too much. Images were layered in Photoshop and masked with luminosity masks. Automatic HDR techniques did not work well as the shortest image was too dark for ACR to find content to register in Merge ot HDR, and in Photoshop the HDR Pro module left visible edge artifacts. The camera was on the iOptron Sky Tracker to follow the sky and register the sky for all the exposures, thus the slightly blurred ground. Taken with the Canon 6D and 15mm full-frame fish-eye lens. — This is a stack of 4 exposures from long to short (8s to 1/2s) to encompass the great range in brightness and not overexpose the crescent Moon too much. Images were layered in Photoshop and masked with luminosity masks. Automatic HDR techniques did not work well as the shortest image was too dark for ACR to find content to register in Merge ot HDR, and in Photoshop the HDR Pro module left visible edge artifacts.
The camera was on the iOptron Sky Tracker to follow the sky and register the sky for all the exposures, thus the slightly blurred ground. Taken with the Canon 6D and 15mm full-frame fish-eye lens.

It was a show of circles and lines, real and imagined, in the morning sky.

With luck, clouds will clear to reveal Comet Catalina, which is likely fainter and less spectacular than hoped. But such is the way of comets. Regardless of what the comet does, it is a good time to be in the desert southwest, typing this blog on a sunny front porch under blue desert skies.

November 14, 2015November 14, 2015

The Visible Ecliptic at Dawn

The morning planets are now strung out along the ecliptic, visualizing this line in the sky.

This was the view this morning, November 14, of the three dawn planets lined up along the ecliptic, with the stars Spica and Regulus also defining this imaginary line.

The ecliptic is the Earth’s orbital path around the Sun projected into the sky. So it is along this line that we see the Sun appear to move around the sky over a year. But it is also the path along which we find the seven other major planets – in this case, three of them: Venus, Mars and Jupiter.

These three worlds were clustered together in October, but are now spreading out along the ecliptic, as Venus drops lower but Mars and Jupiter climb higher.

The stars Spica and Regulus also lie along the ecliptic, where the Moon can occasionally pass in front of, or occult, these stars.

So the two stars and three planets are now nicely drawing the ecliptic line for us in the dawn sky. At this time of year, the ecliptic is also steeply angled above the eastern horizon.

The main image above is a stack of 4 x 20 second exposures for the ground, to smooth noise, and one 20-second exposure for the sky, all with the Nikon D810a at ISO 1000 and Nikkor 14-24mm lens at f/2.8 and at 14mm.

Venus (brightest), with dim Mars above it, then bright Jupiter, in a diagonal line across the dawn sky on November 14, 2015, with the Zodiacal Light barely visible in the brightening twilight sky. Arcturus is a left and Spica is just rising at centre. Corvus is just above the treetops at right. Spica, Venus, Mars and Jupiter more or less define the line of the ecliptic in the autumn morning sky here. This is a stack of 4 x 20 second exposures for the ground, to smooth noise, and one 20-second exposure for the sky, all with the Nikon D810a at ISO 1000 and Nikkor 14-24mm lens at f/2.8 and at 24mm

This image just above is with the same gear but with the lens at the 24mm setting to more tightly frame the planets.

Meanwhile, on the other side of the sky at dawn, Orion and his winter sky friends were setting into the west (image below).

Orion and the winter constellations setting over the old Farmhouse at home, in the dawn twilight on the morning of November 14, 2015. Canis Major and Sirius are at left; Taurus and Aldebaran and the Pleiades are at right. Procyon is at upper left. This is a stack of 4 x 20 second exposoures for the ground to smooth noise and one 20-second exposure for the sky, all with the Nikon D810a at ISO 1600 and 14-24mm Nikkor zoom lens at f/2.8.

All the images here are shot with the Nikon D810a camera and the amazing Nikkor 14-24mm lens, two items in hand this month for testing and review. A thorough test will appear in future blogs.

Of course, as wonderful as the gear is, it cannot extract the ecliptic line and labels from the sky – those are added in Photoshop!

October 20, 2015

Four Planets Along the Morning Ecliptic

Four planets appear in the dawn sky outlining the morning ecliptic.

This morning, October 20, I was able to capture four planets in the morning sky, arrayed along the ecliptic.

From bottom to top they are: Mercury (just past its point of greatest elongation from the Sun), dim Mars, bright Jupiter, and very bright Venus (just 6 days away from its point of greatest elongation from the Sun). Above Venus is Regulus, in Leo.

I’ve added in the labels and the line of the ecliptic, rising steeply out of the east in the autumn dawn sky.

Of course, there is a fifth unlabelled planet in the scene, quite close in the foreground.

The image below is an unlabeled version.

Mercury will be disappearing from view very quickly now as it drops back down toward the Sun.

But over the next week the three higher planets will converge into a tight triangle just 4.5 degrees apart. We won’t see these three planets this close together in a darkened sky until November 2111.

For more information on this week’s dawn sky planet dance see my previous blog entry.

TECHNICAL:
I shot the scene from home in southern Alberta. The image is a composite stack, with manually created masks (not an HDR stack), of 5 exposures, from 15 seconds to 1 second, to contain the range of brightness from the bright horizon to the dimmer star-filled sky higher up. All are with the 35mm lens and Canon 6D at ISO 800.

February 9, 2015

Heads Up! – Comets, Planets, and Zodiacal Light, Oh My!

As the Moon departs the evening sky, we are left with a dark sky for viewing Comet Lovejoy, converging planets, and the elusive Zodiacal Light.

The western sky contains wonders this month.

Look into the evening twilight and you’ll see brilliant Venus appearing a little higher each night. As it climbs up, fainter Mars above is descending closer to the horizon. The two planets are converging toward a spectacular close conjunction with each other, and with the waxing crescent Moon, on February 20.

Meanwhile, Comet Lovejoy (C/2014 Q2) continues to perform well. It is now in the northwestern sky in the early evening, as it travels up through Andromeda into Cassiopeia.

While technically visible to the unaided eye, you really need binoculars or any telescope to see Comet Lovejoy well. Through optical aid it does show a faint tail. But it takes a long exposure photo to show it well.

Here’s where to find Comet Lovejoy over the next couple of weeks, during the current dark-of-the-Moon period.

Look for a fuzzy star in Andromeda. It’s not passing very near any notable deep-sky objects, but its position will still make for a nice wide-angle photo with the comet embedded in this photogenic region of the northern autumn sky.

The other sight to look for each evening for the next two weeks is the Zodiacal Light. My photo shows it from last month, when Comet Lovejoy was crossing the ecliptic.

Look for a pyramid of light stretching up from the sunset point to high in the west. It follows the ecliptic, the green line in the top star chart. It takes a dark sky to see it, and it helps to be at a southerly latitude. But I’ve seen and shot the Zodiacal Light nicely in February from home in Alberta at 51° latitude.

The Zodiacal Light is caused by sunlight reflecting off cometary dust in the inner solar system. To see it, wait for most of the evening twilight to fade away. The glow that’s left brightening the western sky is the Zodiacal Light.

There’s lots to see just in the western evening sky during the next two weeks. Clear skies!

January 17, 2015January 17, 2015

Night of the Comet

What a beautifully photogenic comet Lovejoy is proving to be!

On Friday, January 16, I caught Comet Lovejoy crossing the ecliptic as it travels through Taurus. The long exposure above shows it amid the star clusters, nebulas, and dark clouds of Taurus and Perseus.

The blue Pleiades is at centre, and the red California Nebula is at top. Throughout are the dark tendrils of the dusty Taurus Dark Clouds.

The long blue ion tail of Lovejoy now extends back 15° to 20° on photos and is easy to trace for half that distance in binoculars in a dark sky.

I turned the top photo 90° to orient the comet so it points “down.”

However, this wide-angle nightscape shows the real orientation of the comet, high in the sky above Orion, here rising over the rock formations of City of Rocks State Park, my favourite dark sky site in this area of New Mexico.

Taken earlier in the evening, this ultra-wide image shows the comet at top, with its blue tail oriented along the ecliptic and aligned with the Zodiacal Light, from the glow of sunlight reflecting off comet dust in the inner solar system.

The Zodiacal Light follows the ecliptic, the plane of the solar system and where we find the planets, such as Mars and Venus at bottom here. The comet seems to point toward the Sun, now below the horizon here at the base of the Zodiacal Light. That’s just as it should be! Comet gas tails always point away from the Sun, as they are blown away from the comet’s head by the solar wind.

This night Comet Lovejoy was crossing the ecliptic, as its orbit continues to take it north in a path almost perpendicular to the ecliptic. While planets orbit in the ecliptic plane, most comets do not. They can have orbits oriented at all kinds of angles off the ecliptic plane.

But on January 16 Comet Lovejoy crossed the ecliptic, placing it at the apex of the Zodiacal Light.

This wider view takes in the Zodiacal Light, the comet and Orion rising at left.

This was a marvellous “night of the comet.”