PK219+31.1 or Abell 31 (12-26-2010)

This planetary nebula in Cancer was discovered by George Abell on photographic plates in 1955. It is very dim. Folks with very large amateur telescopes and special filters have trouble seeing it with their eyes. The nebula is relatively nearby, just 1863 light years, give or take 80 or so. Citation. It appears to be interacting with interstellar matter (just my guess), which gives the left side a bow-front or bow-shock look, while the right side trails off; perhaps the nebula is relatively old or weak. Other images show a significant OIII glow near the center. The brightest star in this image, at lower right, is 8.51. A few stars are between 9 and 10, and all others are magnitude 10 or dimmer. The dimmest stars in the image are less than magnitude 17. Here are links to my favorite images of Abell 31: here and here. This image is 14x10' with the Atik 16.

Here is a view with color. In this edition, the nebula has been colored red, the natural color of the Ha emission recorded above. The stars have been left white.

NGC 2174, the Monkey Head Nebula (12-26-10)

This is a better set of data than my first set on this object, which was slightly out of focus. This set is 14x8' with the Atik 16 through an Astronomik 12nm Ha filter and the Orion 120mm achromat w/WO 0.8x II ff/fr (f/4). Perhaps it's time to collect the other narrowband wavelengths.

Christmas Tree Cluster (12-23-2010)

Merry Christmas, everyone!

Of course, there is a reason this cluster is called the Christmas Tree Cluster, NGC 2264. The nebula behind it might be called the Christmas Tree Nebula as well. The brighter parts of the nebula have the shape of a Christmas tree, probably as a result of radiation from cluster stars. Just above the top of the tree is the Cone Nebula. At the bottom left is a complicated web of gas often called the Fox Fur Nebula.

This image is, of course, just the one I took three weeks ago dressed up in Christmas colors (actually, the image is a monochrome image taken through a narrow slice of the deep red part of the spectrum). Enjoy the season!

IC417 (12-1-2010)

IC 417 is a wonderfully complex hydrogen nebula in the constellation Auriga. So many different things to see here!

This image is just 9x8' with the Atik 16 through the Orion 120mm achromat with WO 0.8x II ff/fr (thus at f/4). Processing was done in Nebulosity, Maxim, and PS CS3.

M97 (11-30 and 12-1-2010)

This planetary nebula in Ursa Major is, like all planetary nebulae, an expanding cloud of gas and dust sloughed off a dying star. The star, which you can see in the center of the nebula, is a white dwarf, the super-hot core of what is left of the dying star. The filters used to take this shot cover three wavelengths common to planetary nebulae: Ha, NII, and OIII. In fact, the Ha filter's bandwidth is 12nm wide, and it takes in the NII line. The consequence is that I can't tell whether the red glow in this image comes from hydrogen or nitrogen. The OIII line is far more prominent, however. Ionized oxygen seems to dominate this planetary. M97's distance (and thus its size) are the subject of wildly varying reports, so I have no idea how far away this thing is.

This image is 24x8' with the Astronomik Ha filter and 23x8' with the Astronomik OIII filter. The camera was the Atik 16, and the image was shot through the Orion 120mm achromat with the WO 0.8x II ff/fr, at f/4. Color was done with Cannistra's bi-color technique.

Here is the Ha [+ NII]:
Here is the OIII:

The Squall Line in the Rosette (12-1-2010)

The Rosette Nebula is about 5,000 light years away in the constellation Monoceros. (In wider images, it really does look like a flower. See RoryG's recent image.) A long chain of nebulosity appears in very deep images to connect it to the Cone Nebula complex. (See Wolfgang Promper's image here.) This part of the Rosette Nebula is where clouds of dust and gas in front of all the lit-up ionized hydrogen clouds are silhouetted in the light. The clouds are slowly disintegrating in the ultraviolet radiation from the bright stars in the lower center of the image, the stars of cluster NGC 2244. Yet still tiny pockets of the dark stuff remain randomly ahead of the front, globs dust and gas perhaps shrinking under gravity and resisting the radiation scattering the rest of the matter around them.

This image is 17x8' with the Atik 16 through the Orion 120mm f/5 achromat, the WO 0.8x II ff/fr (so imaging at f/4), and an Astronomik Ha filter.

The Cone Nebula & NGC 2264 (11-30-2010)

This beautiful area of the sky has no bright stars. Without optical aid, it looks empty from the burbs were I live. But with the light pollution extracted, and with a sensitive camera and a large lens to gather and focus the light, great things can be seen.

On the left of this image is the Cone Nebula, a dark cloud that is slowly disintegrating in the radiation generated by the bright stars to the right of it. The cluster of stars, known as NGC 2264, and the cloud of hydrogen gas shown here, can be found about 2,600 light years away. These objects, like the California Nebula, lie in the same arm of the galaxy that we inhabit.

This image is 18x8' with the Atik 16 through the Orion 120mm f/5 achromat and WO 0.8x II ff/fr (so the image was taken at f/4) and an Astronomk 12nm Ha filter.

This image was published in the April 2011 issue of Ciel Extrême, page 15.  Thanks to the editor, Marc Cesarini.  It's a great privilege.

Central California: NGC 1499 (11-30-2010)

This is the central and most interesting (to me) region of NGC 1499, sometimes called the California Nebula. In moderately deep images, the nebula takes on a shape something like that of the state of California. In deeper images, the shape is more like a scimitar (see, e.g., this image from Don Taylor). This much narrower view only shows the Bay Area, the darker cloud in the middle of the image. The bright nebulosity running from upper left to lower center is the coastline. In this relatively deep image, the nebulosity runs into the ocean and out past the edge of the image. The California Nebula is about 1,500 light years away, and is found in the constellation Perseus. It inhabits the same arm of the galaxy that we do.

This image is 13x8' with the Atik 16 through the Orion 120mm f/5 achromat and WO 0.8x II ff/fr and an Astronomik 12nm Ha filter.