Truly Interstellar


M26 Open Cluster and NGC 6712 Globular Cluster

We gaze into the interstellar depths of the Milky Way through uncountable stars.

In this telescopic scene we look toward the Scutum Starcloud, and next spiral arm in from ours as we gaze toward the core of the Galaxy.

The field is packed with stars, seemingly crowded together in interstellar space. In fact, light years of empty space separate the stars, even in crowded regions of the Milky Way like this.

Two dense clusters of stars stand out like islands in the sea of stars. At lower right is Messier 26, an open cluster made of a few dozen stars. Our young Sun probably belonged to a similar family of stars billions of years ago. M26 lies 5,200 light years away.

At upper left is a condensed spot of light, made of hundreds of thousands of density packed stars in the globular cluster known only as NGC 6712. Though much larger and denser than M26, NGC 6712 appears as a tiny spot because of its remoteness – 23,000 light years away, a good part of the distance toward the centre of the Galaxy.

Look carefully (and it may not be visible on screen) and you might see a small green smudge to the left of NGC 6712. That’s a “planetary nebula” called IC 1295. It’s the blown off atmosphere of an aging Sun-like star. It’s what our Sun will become billions of years from now.

At top is a vivid orange-red star, S Scuti, a giant pulsating star nearing the end of its life.

A truly interstellar scene.

– Alan, November 9, 2014 / © 2014 Alan Dyer

 

 

Mars and M22


Mars and M22 Cluster

Mars shines near the globular star cluster Messier 22 in Sagittarius.

This week Mars has been passing near one of the brightest globular star clusters, M22. I caught the pair tonight, November 8, as they sank into the southwestern sky.

The two form a contrasting pair, with red Mars now 260 million kilometres away, far enough that its light takes 13 minutes to reach Earth. However, blue M22 lies so far away, toward the galactic core, that its light take 10,000 years to reach Earth.

Mars appeared closer to M22 earlier this week but tonight was the first night with a narrow window of dark sky between twilight and moonrise, allowing me to shoot the pair.

I shot the image through a telescope with a short focal length of 400mm, taking in a field of about 5 by 3 degrees, the field of high-power binoculars. The image is a stack of eight 2-minute exposures at f/4.5 with the TMB 92mm refractor and Canon 6D at ISO 800.

– Alan, November 8, 2014 / © 2014 Alan Dyer

Nebulas, Clusters and Starfields, Oh My!


Centre of the Galaxy Mosaic

There’s no more spectacular region of the sky than the Milky Way toward the centre of the Galaxy.

What a perfect night it was last night. After moonset between 2 and 3:30 a.m. I shot a series of images around the centre of the Galaxy area and stitched them into a big mosaic of the Milky Way.

The scene takes in the Milky Way from the Eagle and Swan nebulas at top left, down to the Messier 6 and 7 open clusters in Scorpius at bottom. Standing out is the large pink Lagoon Nebula left of centre and the huge region of dark dusty nebulosity popularly called the Dark Horse at right of centre. It’s made of smaller dark nebulas such as the Pipe Nebula and tiny Snake Nebula.

At upper left is the bright Small Sagittarius Starcloud, aka Messier 24, flanked by the open clusters M23 and M25. There are a dozen or more Messier objects in this region of sky.

The actual centre of the Milky Way is obscured by dark dust but lies in the direction just below the centre of the frame, amid one of the bright star clouds that mark this amazing region of sky.

I shot the images for this mosaic from a site near Portal, Arizona, using a 135mm telephoto lens and filter-modified Canon 5D Mark II riding on an iOptron SkyTracker to follow the stars. The mosaic is made of 6 panels, each a stack of five 3-minute exposures. They were all stacked and stitched in Photoshop CC. The full version is 8000 by 9000 pixels and is packed with detail.

I think the result is one of the best astrophotos I’ve taken! It sure helps to have Arizona skies!

– Alan, May 5, 2014 / © 2014 Alan Dyer

 

 

Our Neighbour Galaxy, the Large Magellanic Cloud


Large Magellanic Cloud (77mm Borg & 5DII)

One of our nearest galactic neighbours contains an astonishing collection of nebulas and star clusters.

This is the money shot — top of my list for targets on this trip to Australia. This is the Large Magellanic Cloud, a satellite galaxy of our Milky Way. At “just” 160,000 light years away, the LMC is in our galactic backyard. Being so close, even the small 77mm telescope I used to take this image resolves numerous nebulas, star clusters, and a mass of individual stars. The image actually looks “noisy” from being filled with so many stars.

I’ve oriented and framed the Cloud to take in most of its main structure and objects. One can spend many nights just visually exploring all that the LMC contains. It alone is worth the trip to the southern hemisphere.

At left is the massive Tarantula Nebula, a.k.a. NGC 2070. At upper right is the LMC’s second best nebula, the often overlooked NGC 1763, also known as the LMC Lagoon. In between are many other magenta and cyan tinted nebulas.

I’ve shot this object several times but this is my best shot so far I think, and my first with this optical system in several years.

I used a Borg 77mm aperture “astrograph,” a little refractor telescope optimized for imaging. It is essentially a 330mm f/4 telephoto lens, but one that is tack sharp across the entire field, far outperforming any camera telephoto lens.

This shot is a stack of six 10-minute exposures at ISO 800 with the filter-modified Canon 5D MkII camera. The autoguider worked perfectly. And yet, I shot this in clear breaks between bands of clouds moving though last night. The night was humid but when the sky was clear it was very clear.

Next target when skies permit: the Vela Supernova Remnant.

– Alan, March 25, 2014 / © 2014 Alan Dyer

 

A Dreamy Carina Nebula


Carina Nebula in Haze (77mm 5DII)

The Carina Nebula glows among the colourful southern stars.

I’ve shot this field many times over the years in visits to the southern hemisphere but never with a result quite like this. Last night the sky was hazy with high cloud but I shot anyway. The result is a “dreamy” rendition of the Carina Nebula and its surrounding clusters of stars. At upper left is the Football Cluster, NGC 3532, while at upper right is the Gem Cluster, NGC 3293.

As with my previous post, the haze brings out the star colours, filling the field with pastel shades. It is one of the finest fields in the sky, worth the trip down under.

Alas, skies have clouded up tonight with only a few bright stars and Mars shining through. And the forecast is for rain for the next few days. So I may get lots of writing done at my Aussie retreat.

As a technical note: I shot this with the little 77mm Borg Astrograph, essentially a 300mm f/4 telephoto lens that is tack sharp across a full frame camera, like the Canon 5D MkII I used here. It was riding on my Astro-Physics 400 mount and guided flawlessly with the Santa Barbara SG4 auto-guider. The image is a stack of four 8-minute exposures. All the gear, much of it stored here in Australia between my visits, is working perfectly.

– Alan, March 23, 2014 / © 2014 Alan Dyer

 

The Pleiades – The Stellar Seven Sisters


M45, the Pleiades Cluster (92mm 5DII)

The stars of the Pleiades sit amid a dusty sky in Taurus.

These are the famous Seven Sisters of Greek legend, known as the Pleiades. They are the daughters of Atlas and Pleione, who are also represented by stars in the cluster. Many cultures around the world tell stories about these stars, but in Greek tradition their appearance signalled the summer sailing season in the Mediterranean. The Pleiades first appear at sunset in the eastern evening sky in autumn and put in their last appearance in the western sky in spring.

One story has it they were placed in the sky to recognize their devotion to their father Atlas and his unending labour in holding up the heavens. They are the half-sisters of the Hyades, another nearby cluster of stars in Taurus. Other stories describe the Pleiades as the Seven Doves that carried ambrosia to the infant Zeus.

A seldom-used name now for this cluster is the Atlantides, from the plural form of Atlas, their father. Thus, these sisters gave their name to the Atlantic Ocean, a vast and uncharted sea until the 16th century. The term “atlas,” first used by Mercator for a book of maps, comes not from the Pleiades’ father but from a real-life king in Morocco who supposedly made one of the first celestial globes.

I shot this portrait of the Sisters a few nights ago, stacking a set of five 15-minute exposures with the TMB 92mm refractor and Canon 5D MkII at ISO 800. I processed the image to bring out the faint clouds of dust that pervade the area.

The Pleiades are passing through dust clouds in Taurus and lighting them up. The stars are embedded in dust, lit blue by the light of the hot stars. But even farther out you can see wisps of dust faintly illuminated by the light of the Pleiades.

The stars are thought to be about 100 million years old, quite young as stars go. They formed together in a massive nebula that has long since dissipated, and will travel together for another few hundred million years until the sister stars go their own way around the Galaxy. The stellar family that gave rise to so many legends around the world will be scattered to the stars.

– Alan, October 12, 2013 / © 2013 Alan Dyer

A Star-Filled Scene in Cassiopeia


M52 & NGC 7635 Bubble Nebula (92mm 5DII)

A star cluster and nebulas highlight a glorious starfield in Cassiopeia.

I shot this three nights ago on a very clear autumn evening. The telescope field takes in the star cluster Messier 52 at upper left, a cluster of 200 stars about 5000 light years away. It is one of the best objects of its class for viewing in small telescopes. Charles Messier found it in 1774 as part of his quest to catalog objects that might be mistaken for comets.

The brightest area of nebulosity below M52 is the Bubble Nebula, aka NGC 7635, found in 1787 by William Herschel. It’s an area of star formation marked by a central bubble of gas (just visible on the scale of my photo) being blown by the winds from a hot central star. The Bubble can be seen in amateur telescopes but is a tough target to spot.

Above the Bubble is a small bright nebula, NGC 7538.

Below the Bubble lies a larger claw-like nebula known only as Sharpless 2-157, an object that shows up only in photos.

In all, it’s a complex and beautiful field, set in the constellation of Cassiopeia the Queen.

A footnote for the technically minded: This is a stack of 5 x 15 minute exposures with a filter-modified Canon 5D MkII at ISO 800 shooting through a TMB 92mm apo refractor at f/4.8, mounted on an Astro-Physics Mach 1 mount guided by a Santa Barbara SG-4 autoguider.

– Alan, October 11, 2013 / © 2013 Alan Dyer