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

 

 

The Eagle and the Swan


Though they are truly “nebulous,” these clouds of interstellar gas carry fanciful names — our human attempt to make sense of the vast chaotic forms that pervade deep space.

Above is the Eagle Nebula, a.k.a. Messier 16. Below lies the Swan Nebula, a.k.a. Messier 17. Through a telescope to the eye these nebulas do take on the imagined shape of interstellar birds flying along the Milky Way. But long exposure images like this bring out far more than the eye can see. The entire field, here about the width of what high-power binoculars take in, is filled with swirls of hydrogen gas, glowing in its characteristic red colour.

The Eagle Nebula lies in the constellation of Serpens the serpent, while the Swan Nebula lies just over the border in Sagittarius the archer.

I took this shot Saturday night, July 30, 2011, on one the few perfect nights of observing we get here in Canada — the night was warm, dry, with little wind and no mosquitoes. I could venture out with just a sweater on for a bit of warmth. A far cry from the parkas and down-filled boots normally needed.

This field is a first for me from Canada. I’ve shot it from Australia and Chile, where these objects lie overhead, never from home in Alberta at a latitude of 51° North. But the night was so transparent, the field was worth going after, despite it being low on the southern horizon and at its best for no more than an hour after it got dark.

To shoot the field, I used the wonderful little Borg 77mm f/4 astrographic refractor, effectively a 300mm telephoto lens but far sharper and flatter than most telephotos made for sports and wildlife. The camera was the Canon 5D MkII, a filter-modified version that has a special filter for passing more of the deep red colour of hydrogen. But the real difference here was the use of a filter at the focus of the telescope that further isolated the red wavelengths and blocked other colours that might have otherwise fogged the image, especially from a field so low on the horizon. It worked great, though does tend to render the whole field on the red side.

— Alan, July 31, 2011 / Image © 2011 Alan Dyer