Shooting the Heart Nebula


Testing the Nikon D810a

Last night I shot into the autumn Milky Way at the Heart Nebula.

I’m currently just finishing off a month of testing the new Nikon D810a camera, a special high-end DSLR aimed specifically at astrophotographers.

I’ll post a more thorough set of test shots and comparisons in a future blog, but for now here are some shots from the last couple of nights.

Above is the setup I used to shoot the image below, shot in the act of taking the image below!

The Nikon is at the focus of my much-loved TMB 92mm refractor, riding on the Astro-Physics Mach One mount. The mount is being “auto-guided” by the wonderful “just-press-one-button” SG-4 auto-guider from Santa Barbara Instruments. The scope is working at a fast f/4.4 with the help of a field flattener/reducer from Borg/AstroHutech.

I shot a set of 15 five-minute exposures at ISO 1600 and stacked, aligned and averaged them (using mean stack mode) in Photoshop. I explain the process in my workshops, but there’s also a Ten Steps page at my website with my deep-sky workflow outlined.

IC 1805 Heart Nebula (92mm D810a)
The Heart Nebula, IC 1805, in Cassiopeia, with nebula NGC 896 at upper right and star cluster NGC 1027 at left of centre. This is a stack of 15 x 5-minute exposures with the Nikon D810a as part of testing, at ISO 1600, and with the TMB 92mm apo refractor at f/4.4 with the Borg 0.85x field flattener. Taken from home Nov 29, 2015.

The main advantage of Nikon’s special “a” version of the D810 is its extended red sensitivity for a capturing just such objects in the Milky Way, nebulas which shine primarily in the deep red “H-alpha” wavelength emitted by hydrogen.

It works very well! And the D810a’s 36 megapixels really do resolve better detail, something you appreciate in wide-angle shots like this one, below, of the autumn Milky Way.

It’s taken with the equally superb 14-24mm f/2.8 Nikkor zoom lens. Normally, you would never use a zoom lens for such a demanding subject as stars, but the 14-24mm is stunning, matching or beating the performance of many “prime” lenses.

The Autumn Milky Way (Perseus to Cygnus)
The Milky Way from Perseus, at left, to Cygnus, at right, with Cassiopeia (the “W”) and Cepheus at centre. Dotted along the Milky Way are various red H-alpha regions of glowing hydrogen. The Andromeda Galaxy, M31, is at botton. The Double Cluster star cluster is left of centre. Deneb is the bright star at far right, while Mirfak, the brightest star in Perseus, is at far left. The Funnel Nebula, aka LeGentil 3, is the darkest dark nebula left of Deneb. This is a stack of 4 x 1-minute exposures at f/2.8 with the Nikkor 14-24mm lens wide open, and at 24mm, and with the Nikon D810a red-sensitive DSLR, at ISO 1600. Shot from home, with the camera on the iOptron Sky-Tracker.

The D810a’s extended red end helps reveal the nebulas along the Milky Way. The Heart Nebula, captured in the close-up at top, is just left of centre here, left of the “W” forming Cassiopeia.

The Nikon D810a is a superb camera, with low noise, high-resolution, and features of value to astrophotographers. Kudos to Nikon for serving our market!

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

 

Last of the Summer Milky Way


Last of the Summer Milky Way

The summer Milky Way sets into the southwest on a late November night. 

On Saturday, November 28, well into winter here in Alberta, the stars of the Summer Triangle and the summer Milky Way set into the southwest on a clear, though slightly hazy, late November night.

This is the last of the summer Milky Way, with the centre of the Galaxy now long gone, but the Summer Triangle stars remaining in the evening sky well into autumn. Glows from light pollution in the west light the horizon, in a quick series of images shot in my rural backyard.

In the Summer Triangle, Vega is at right, as the brightest star; Deneb is above centre, and Altair is below centre, farthest south in the Milky Way.

I shot this as a test image for the Nikkor 14-24mm lens, here wide-open at f/2.8 and at 14mm, where it performs beautifully, with very tight star images to the corners. It does very well at 24mm, too! This is astonishing performance for a zoom lens. It matches or beats many “prime” lenses for quality.

The camera was the 36-megapixel Nikon D810a, Nikon’s “astronomical DSLR” camera, also on test. Here it shows its stuff by picking up the red nebulas in Cygnus and Cepheus.

Thorough tests of both the camera and lens will appear later in the year. Stay tuned.

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For the even more technically-minded, this image is a stack, mean combined, of five 2-minute tracked exposures, at f/2.8 and ISO 800. The camera was on the iOptron Sky-Tracker. So the stars are not trailed but the ground is! I made no attempt here to layer in an untracked ground shot, as there isn’t much detail of interest worth showing, quite frankly.

At least not in the ground. But the Milky Way is always photogenic.

– Alan, November 28, 2015 / © 2015 Alan Dyer / www.amazingsky.com

 

The Visible Ecliptic at Dawn


Venus (brightest), with dim Mars above it, then bright Jupiter, in a diagonal line across the dawn sky on November 14, 2015. Regulus and Leo are at top right, Arcturus in Bootes is at left, and Spica in Virgo is just rising at centre. Spica, Venus, Mars, Jupiter and Regulus 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 14mm

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
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.
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!

– Alan, November 14, 2015 / © 2015 Alan Dyer / amazingsky.com