emission nebula – The Amazing Sky

November 18, 2014

Both the Heart and Soul of Cassiopeia

Here are both the heart and the soul of Cassiopeia the Queen.

Two days ago I posted an image of the Soul Nebula. Now, here is the matching Heart Nebula, in a mosaic of the glorious region of the Milky Way called the Heart and Soul Nebulas located in the constellation of Cassiopeia.

They are otherwise respectively called IC 1805 and IC 1848. Amid the swirls of nebulosity are numerous clusters of stars, such as NGC 1027 just above centre. The separate patch of nebulosity at upper right is NGC 896.

I shot the frames for this 3-segment mosaic over two nights, with one segment taken from the frames that made up the previous post. Plus I shot two others to span the region of the Milky Way that is about seven degrees long, a binocular field.

Each of the 3 segments is a stack of 12 frames, with each frame a 6-minute exposure. I used the filter-modified Canon 5D MkII and shot through the TMB 92mm apo refractor at f/4.4. All processing was in Photoshop, including the mosaic assembly.

In all, it’s the best image I’ve taken of this much-shot area of the sky. It really brings out the diversity in star colours, and sky colours, from the dusty orange-brown region at left, to the inky dark dustless region at far right.

November 16, 2014

The Soul of Cassiopeia

The Soul Nebula glows from within the constellation of Cassiopeia the Queen.

I shot this image last night, capturing an object prosaically known as IC 1848, but more popularly called the Soul Nebula.

It is often depicted framed with a companion nebula just “off camera” here to the right, called the Heart Nebula. Thus they are the Heart and Soul. Both shine on the eastern side of Cassiopeia the Queen.

Here I’m framing just the Soul, taking in some of the faint nebulosity to the left of the main nebula, including a tiny object called IC 289, a star-like planetary nebula at upper left.

I like this image for its variety of subtle colours, not only the reds and magentas in the bright nebula, but also in the dark sky around it from dim dust adding faint yellows, browns and even a touch of green.

The Soul Nebula lies 6,500 light years away in the Perseus Arm, the next spiral arm out from ours in the Milky Way. On northern autumn nights this region of the sky and Milky Way lies high overhead.

For the technically minded:

The image is a stack of 20 six-minute exposures, taken with a filter-modified Canon 5D Mark II at ISO 800. I was shooting through one of my favourite telescopes for deep-sky photography, the TMB (Thomas M. Back-designed) 92mm apo refractor, working at a fast f/4.4 using a Borg 0.85x field flattener and focal reducer.

I used one of Noel Carboni’s “Astronomy Tools” Photoshop actions to add the “diffraction spikes” on the stars. They are artificial (refractors don’t produce spikes on stars) but they add a photogenic touch to a rich starfield.

I shot this from the backyard of my New Mexico winter home.

April 17, 2014

Star Scenes in Scorpius

Scorpius, one of the most photogenic of constellations, contains a wealth of amazing sky sights.

My trip to the land down under is coming to an end but I’m still working through the dozens of deep-sky images I was able to take under the southern stars. The wide-field scene above takes in all of Scorpius, shot with the constellation sitting directly overhead in the pre-dawn hours of an austral autumn. You can trace the scorpion’s winding shape down from his head and claws at top, to his curving stinger tail at bottom.

Off the stinger of the scorpion shine two naked-eye star clusters, Messier 6 and 7 (the close-up photo above). M6 is the Butterfly Cluster, seen here sitting in a dark region of the Milky Way at upper right. Its companion, M7, a.k.a. Ptolemy’s Cluster at left of the frame, is lost amid the bright star fields that mark the direction of the galactic core.

In the curving tail of the scorpion lie two patches of nebulosity. At upper left is NGC 6357, but the triple-lobed NGC 6334 at bottom right is also known as the Cat’s Paw Nebula.

Further up the tail of the scorpion sits this fabulous region of space that is a stunning sight in binoculars. NGC 6231 is the blue star cluster at bottom, which garnered the name The False Comet Cluster back in early 1986 when many people mistook its fuzzy naked eye glow for Comet Halley then passing through the area. The camera reveals the region filled with glowing hydrogen gas.

But the standout region of Scorpius lies at its heart. Here, the yellow-orange star Antares lights up a dusty nebula surrounding it, reflecting its yellow glow. At top, another dusty nebula surrounds the star Rho Ophiuchi, reflecting its blue light. Glowing hydrogen gas adds its characteristic magenta tints. This is one of the most colourful regions of the Milky Way.

I shot these images with 50mm normal and 300mm telephoto lenses two weeks ago during the OzSky Star Safari near Coonabarabran, NSW, Australia. For all I used a filter-modified (by Hutech) Canon 5D Mark II camera.

September 25, 2012September 25, 2012

Star Birth Site

In contrast to last Saturday’s post, Star Death Site, this is a place where stars are born.

This magenta cloud is where dozens of new stars are forming. One centre of star formation is the finger at right jutting into the hollowed out core of the nebula. Ultra-violet radiation from nearby hot stars is eroding away this dark finger of dust and gas, causing its rim to glow. This is a feature similar to the famous “Pillars of Creation” depicting in Hubble Space Telescope views of another nebula, the Eagle Nebula. However, this giant wreath of hydrogen 3000 light years away has no name, just the catalog number IC 1396. It’s in Cepheus, high in the northern autumn sky.

An added attraction of the scene is the orange star at top, Herschel’s Garnet Star, a.k.a. mu Cephei. This red supergiant is one of the largest stars known. If it replaced our Sun the Garnet Star would engulf all the planets out to Jupiter. Including its profuse radiation emitted in the infrared, the Garnet Star outshines the Sun by 350,000 times. It is squandering its energy so quickly this supergiant is destined to explode as a supernova, perhaps leaving behind a remnant like the Veil Nebula I described in that earlier blog from a few days ago.

These deep space wonders are all part of the great cycle of stardust that fuels the Galaxy.

August 8, 2012

Continent in the Sky

Shining overhead on northern summer nights right now is the blue supergiant star Deneb, in Cygnus. Nearby glow the magenta clouds of the North America Nebula.

This image shot with a telephoto lens takes in roughly the same field of view as a pair of binoculars. But being a long time exposure it reveals much more of the faint nebula than even the aided eye can see. However, even binoculars will show a greyish cloud near Deneb in roughly the shape of North America. It is actually a continent of stars and hydrogen gas, glowing with hydrogen’s characteristic magenta colour, a mix of deep red and blue emission lines. The gas may be electrified into glowing by the searing radiation from the star Deneb, some 1400 light years away from Earth.

I shot this on a July night, with some haze passing by during some of the exposures. The haze added the photogenic glows around the stars.